7 Types of Acne: Causes, Symptoms, and Treatments

Acne (acne vulgaris) is a common skin condition that develops when excessive oils from the sebaceous glands and dead skin cells clog the skin pores, causing various lesions. This situation allows opportunistic bacteria (like Cutibacterium acnes, previously known as Propionibacterium acnes) to proliferate and cause infections. Besides these factors, many other risk factors like genetics, smoking, exposure to sunlight, radiation and chemicals, use of some drugs and poor hygiene etc, also have a role. Some hormones, like androgens, influence the development of acne by controlling sebum production. 

It is widespread and affects hundreds of millions worldwide, making it one of the most common diseases globally. In the UK, 95% of youth (age group 11-30 years) develop some form of acne. The most susceptible age in boys and girls is 16-19 years and 14-17 years, respectively. The risk and incidence are exceptionally high in the developed and industrialized countries. Nevertheless, some people experience it well into their twenties, thirties, and even beyond, and 3% of adults experience it after age 35. It develops on any skin and all over the body, particularly the face, back and upper back and is primarily a problem of oily skin having excessive oil glands. It is a complicated skin issue and causes various skin lesions and blemishes with specific causes, symptoms and treatment options. 

The term ‘breakout’ is generalized for all types of acne but is a misnomer as all types do not spread out on the skin. Acne is divided into various types based on multiple criteria. Based on the severity of the condition, it could be mild, moderate or severe. Based on the age of development, it is; 

1. Infant acne: The type of acne that develops in children under one year of age. 
2. Childhood acne: The acne that develops in children 1-12 years of age
3. Teenage acne: The acne that develops in teenage age (13-19).
4. Adult acne: The acne that develops past teenage. 

Based on causative factors, it is categorized as;  

1. Cosmetic acne: Mild acne resulting from certain comedogenic skincare products.
2. Mallorcan acne: Skin eruptions caused by exposure to ultraviolet radiations. 
3. Chemical acne: Acne develops due to exposure to certain chemicals. 

The most commonly used criteria for the classification of acne is based on the types of lesions. On this basis, it could be;

1. Non-inflammatory acne: This type doesn’t involve any inflammatory reactions and includes whiteheads (closed comedones), blackheads (open comedones) and milia. 
2. Inflammatory acne: This type involves inflammatory reactions, including nodules, pustules, papules, and cysts. 

All these lesions have psychological repercussions and cause anxiety, depression, poor self-esteem and even suicidal thoughts, particularly in young people. 

Various treatment options for acne are used to avert these situations, like medications, medical procedures and lifestyle and nutritional factors. Working on nutritional and lifestyle factors like lowering the intake of sugars and carbohydrates, lowering stress, etc., help to manage acne. Various treatment options are available, and the choice depends upon the type of acne, the severity of the condition, previous experience with the drug, gender and the presence or absence of other diseases. The standard treatment options are topical preparations containing salicylic acid, benzoyl peroxide, retinoids and azelaic acid, topical oral or systemic antibiotics to control infections and anti-inflammatory drugs to manage the pain and inflammation. Sometimes hormonal contraceptives help, mainly if the cause is hormonal changes (hormonal acne). Medical professionals recommend early and timely treatment to avoid unwanted complications and severe outcomes like persistent scars.

It is essential to recognize the type of acne by identifying signs and symptoms and seeking the help of skin specialists.

Milia

Milia are tiny, whitish, transient and benign keratin cysts on the skin. They are also known as oil seeds or milk spots. Although they develop in all ages, the newborn is particularly susceptible, and 40-50% of healthy babies develop it. Milia develop when the dead skin cells and keratin are not sloughed timely, are trapped under the new skin, and are hardened to form a milium (singular of milia). 

The causative risk factors are skin injury, exposure to radiation, chemicals and sunlight, prolonged use of steroids, genetics, autoimmune diseases, unsafe cosmetic products, improper skin care, lack of sleep and other skin conditions like eczema and psoriasis etc. The milia are different from other acne lesions and are dome-shaped, whitish to yellow bumps and are not associated with pain or itchiness. They mainly develop on the cheeks and nose and often occur in groups. Babies are sometimes born with the milia, while childhood acne doesn't last several weeks after birth. 

The development of characteristic bumps on the skin of a newborn at the time of birth or immediately after the birth signals the milia. The most common sites of developing milia are under the eyes, on the eyelids, nose, forehead, cheek, legs, arms, genitals, and inside of mouth and chest. In adults and older children, they cause skin damage leading to issues like blistering. 

The congenital milia are not harmful; treatment is unnecessary as they resolve spontaneously within a few days. However, they cause blemishes on the skin, and the parents must consult the doctor for treatment. The milia developing in older children and other types like secondary Mila need treatment. The treatment options for newborn babies are limited and should be consulted with a dermatologist. 

The standard treatment options are the use of OTC products like adapalene gel, prescription creams (like tretinoin cream) in severe cases, surgical removal by the surgeon (puncturing the bumps with a fine needle and squeezing out the internal contents and debris), the cryotherapy (in which, the spots are frozen and removed), and the use of medicated creams (like antibiotic creams) to treat skin infections and milia en plague. Some other treatment options are deroofing (the use of a sterile needle to collect the contents), the use of chemical peels to remove the worn-out outer skin (in older children), laser ablation (the use of laser beams to target and destroy the cysts), diathermy (the use of heat to obliterate the cysts) and the surgical scraping and cauterization of the cysts (destruction curettage). 

The milia and other acne lesions have many things in common, but there are many differences, and it is essential to differentiate them. For differentiation, the following criteria are used;

The appearance of lesions: The milia are whitish-to-yellow bumps that are smaller in size and appear mainly on the skin of the face. They are often raised, firm and rounded. The milia are not inflamed. The acne lesions, on the other hand, could be inflammatory (cysts, nodules and pustules) or non-inflammatory (blackheads and whiteheads). The inflammatory lesions are red and painful red due to inflammation and contain pus or other discharges. 

Location of lesions: The milia lesions appear mostly on cheeks, eyes and nose, while the acne lesions develop anywhere on the body, particularly on the chest, neck, face and back.

Causative agents: Milia occur due to the improper shedding of dead cells, and some other risk factors like injuries, burns, or skin trauma also increase the risk. The acne lesions are related to increased oil production, leading to the blockage of skin pores and the resulting bacterial infections. 

Treatment options: Milia need an exfoliator, a gentle scrub and retinoid cream in severe cases, and surgical treatments are also helpful. The acne is treated with oral and topical OTC and prescription drugs. The OTC products contain low-strength salicylic acid, and benzoyl peroxide, while high-strength products and oral antibiotics are effective in severe cases. In short words, acne needs more aggressive treatment.

In newborn babies, the milia last for a few days to weeks, while in adults and older children, it lasts for a few weeks to months. They don't leave scars in most cases. In both cases, they leave independently without any intervention; if they don't, the parents should consult the doctor.

Blackheads (Open Comedones)

Blackheads are tiny, darker comedones that develop on the nose, chin, cheeks, face, forehead and other body parts. The blackheads are not painful, but they are cosmetic blemishes, especially those developing in the location of high visibility. They are formed when a combination of dead skin cells and sebum clogs the skin pores or hair follicles. However, unlike nodules and cysts, the blackheads are not inflammatory and don't cause pain and redness. They develop all over the skin, like on the back, chest and neck, but the skin with high oil production, like on the face, is particularly susceptible. 

The blackheads are easily identifiable as they are like smaller black dots. The black colour of blackheads is due to the oxidation of skin pigment melanin after exposure to the air. The number of blackheads on the skin is used to classify the acne as mild, moderate or severe. 

The blackheads develop similarly to other acne lesions, clogging hair follicles, with debris being the leading cause. The waste includes dead skin cells and the oil glands' oil. The sebum is the major oily secretion secreted by the sebaceous glands. It consists of fatty acids and triglycerides and keeps the skin healthy and moisturized. Although the normal production of sebum is necessary, some factors cause the overproduction of sebum and increase the likelihood of developing acne and blackheads. The cellular turnover in the skin (epidermal turnover) causes the removal of dead skin cells and their replacement with healthy cells. 

Whenever the epidermal turnover is increased due to skin damage due to exposure to sunlight, radiation and chemicals, the excessive dead cells accumulate on the skin in the form of layers of dead cells. These cells combine with excessive oil on the skin to form debris that clogs the skin pores. During the development of a blackhead, a tiny opening is left in the clogged hair follicle that causes the oxygen to reach the debris, causing oxidation and black colour. It is the reason why it is called open comedones. 

Some factors that influence oil production and cellular turnover are hormones (high androgens, DHT, and testosterone stimulate the oil glands to secrete more sebum), the use of certain oil-based skincare products, genetics (some acne related traits like the proportion of branched-chain fatty acids in the sebum etc., are inherited), the use of certain medications (like lithium, steroids and anticonvulsants), the use of a specific type of clothes (the fabrics made from non-breathable material and the cloths that rub against the skin tightly like backpacks, headbands etc.), smoking (some chemicals in the cigarette smoke increase inflammation and suppress immunity) and stress (high levels of stress increase cortisol levels which stimulate the oil glands, suppress the functions system) and eating certain foods (like sugary drinks and carbohydrate-rich foods like potatoes and white bread). 

The black colour of blackheads makes them highly visible on the skin. They are not inflamed or painful and are slightly raised. The blackheads are dark and open bumps on the skin that are not painful. The OTC products, prescription medications and some procedures like laser therapy, chemical peels, microdermabrasion and manual removal procedures are effective for treatment. 

OTC products: Many acne medications, such as creams, pads, gels or ointments, are available at grocery and drug stores. They contain ingredients like resorcinol, benzoyl peroxide and salicylic acid and cause the removal of dead skin cells, dryness and death of causative bacteria. 

Prescription medications: Prescription medications containing antibiotics, benzoyl peroxide, adapalene, azelaic acid, tazarotene, tretinoin and vitamin A are available. These medications are applied on the skin or taken orally to prevent skin clogging and improve cellular turnover. 

Manual removal: This technique uses an extractor to pull the plug, and a dermatologist performs the procedure. 

Microdermabrasion uses a rough surface to scrub the top layer of the skin and remove the clogs that cause blackheads. Likewise, the chemical peels remove the dead cells and clogs. The Milder peels can be self-performed, while stronger peels need to be applied and used by the dermatologist. 

During laser therapy, light beams or lasers kill bacteria and destroy the sebaceous glands (thus lowering oil production). 

The blackheads are distinct from other acne lesions, and here are how they are different from them;

Whiteheads: The whiteheads don't have skin pores and are covered by the skin. As a result, they are not oxidized and appear as whitish bumps on the skin. 

Cysts: The cysts are pus-filled, deep-seated and more extensive lesions. They are painful and often leave scars. 

Pustules are also known as pimples and are yellowish to whitish. They are inflammatory lesions and contain pus. 

Papules are also inflammatory, raised and reddish bumps that are smaller. They are painful to touch but don't contain pus. 

The time taken for removal depends upon the depth of the blackheads. If the blackheads are on the skin's top surface and are not too deep, they likely disappear within 3-6 weeks. If, however, they are embedded deep in the skin, they are not expected to disappear by themselves and need to be treated or removed by the dermatologist.

Papules

A papule is a small-sized reddish bump on the skin. It is an inflammatory acne lesion, but it doesn't have a pus-filled centre. When pus fills, the papule becomes pustule. It is smaller, with a diameter of 5mm or less but has a considerable size variation ranging from a pinhead to close to 10mm at the widest point. 

A papule develops when the dead skin cells and the excessive oil produced by the Sebaceous glands clog the skin pores, causing a blockage known as a comedo. The trapped oil serves as food for the trapped bacteria, which cause an infection. Initially, a smaller version of comedones (microcomedone) forms, developing into a larger someone later. The rupture of this comedone causes the deep penetration of the skin by the bacteria, and the resulting immune response causes the development of papules. 

The bumps are easily identifiable as they are smaller in size, just the width of a fingernail and are either dome-shaped or have a flat top. Sometimes, the papules have a central smaller impression like a navel (umbilicated). The umbilicated papules develop in some diseases like Molluscum contagiosum. The bumps are also identified by their colour and typical appearance, e.g., raised bumps on the skin, pinkish or reddish, painful and tender to touch, and the absence of pus.

The primary cause of pimples is the same as general causes of acne, e.g., excessive oil production, skin colonization by dangerous bacteria, and high levels of androgens and other male hormones. Some risk factors like stress, the use of drugs like antidepressants and corticosteroids, and eating high sugar and carbohydrate diets trigger or increase the severity of the condition. 

For treatment, the doctors often start with nonprescription OTC preparations, which contain salicylic acid or benzoyl peroxide. If these products don't work, some oral medications are recommended, and in severe cases, the patients are referred to the dermatologist for proper treatment. The commonly used topical treatments for papules are the retinoids and related drugs like tazarotene, tretinoin and adapalene, and topical antibiotics to kill bacteria on the skin like clindamycin and erythromycin. Sometimes, these antibiotics are combined with retinoids for better results. 

The prescription drugs given through the oral route include antibiotics like minocycline, tetracycline, doxycycline, erythromycin or azithromycin, combined hormonal contraceptive (which contain both oestrogen and progesterone), and anti-androgens like spironolactone to lower the levels of androgens or prevent them from influencing the oil glands.

Papules have many similarities and differences from other acne lesions, like, 

Blackheads: the papules are small-sized dark spots, and in contrast to the papules, the blackheads are not inflammatory lesions and thus don't cause inflammation and redness. 

Whiteheads: The whiteheads are also non-inflammatory acne lesions and thus don't cause inflammation and redness. They are tiny spots and are not reddish and raised. 

Pustules: The pustules are small-sized inflammatory and pus-filled bumps on the skin. Unlike the papules, the pustules contain pus consisting of dead bacteria, skin, and white blood cells.

Nodules: The nodules are more prominent and a more severe form of acne and have a deeper root in the skin than a papule. They are also painful. So, the nodule is similar to the pimple as both are inflammatory lesions and are raised and red. However, the nodules are much larger in size. 

The duration of papules depends upon the factors like the skin type, the severity of symptoms and genetics. Generally speaking, the blemishes last anywhere from few days to weeks, even months or longer. The skin's natural immunity and healing process reduce the appearance of scars with time. However, untreated and severe papules cause scarring and hyperpigmentation of the skin.

Whiteheads (closed comedones)

Whiteheads are acne lesions that develop when the dead skin cells and oil from the sebaceous glands seals off the gland ducts or hair follicles to form a closed bump known as a closed comedo. The contents are not exposed to air (as in blackhead), so no blackening occurs. They are ubiquitous, and the epidemiological research has found that almost everyone experiences whiteheads at some point in life. 

Adolescent boys and girls are more susceptible, although it occurs in adults too, accounting for 10-20% of the cases. The whiteheads are so apparent on the skin that the help of a healthcare professional is not required to identify them. They occur mainly on the skin, which has many sebaceous glands, like on the forehead and face, and also develop in the neck, shoulders and chest. 

The clogged skin pores develop whiteheads, so any factor causing the clogging of pores causes whiteheads. The increased production of sebum from the skin is triggered by hormonal changes, particularly during puberty, menstruation, pregnancy and menopause, and due to the use of progesterone-containing contraceptives. Specific genes related to sebum production are inherited, so people with a history of acne are more prone to develop whiteheads. Likewise, some physical causes, like friction on the skin (e.g., chin friction due to chin strap) etc., also causes acne. Some other responsible factors are the abnormalities in the keratin formation, the protein that makes the nails, skin and hairs and increased bacterial colonization of the skin due to poor hygiene and skin infections.  

Whiteheads are non-inflammatory acne lesions and they represent a milder form of acne. The main symptom is the development of yellowish-to-whitish bumps on the affected skin. These bumps are often very tender to the touch. Sometimes, the density of lesions is very low. 

Like other acne lesions, Whiteheads are treated through OTC products, prescription medications, and procedures. The OTC products used for this purpose include,

Retinoids: These are the vitamin A derivatives. They are mostly available OTC, while some preparations need a prescription (like Differin). They prevent the clogging of skin pores and break blackheads and whiteheads. They peel the skin and cause a colour change. 

Salicylic acid: It is available in different OTC lotions and cleansers. It peels the skin to remove the top layer of dead skin cells, thus preventing the clogging of hair follicles. 

Benzoyl peroxide: It is present in several OTC skin products, such as face washes and leaves on gels. It destroys the bacteria found on the skin that cause acne. Its high concentration causes skin dryness and irritation and lower concentrations are safer. 

Azelaic acid: It is a natural acid that reduces swelling and inflammation by killing bacteria and other microorganisms on the skin. The products containing 15-20% azelaic acid are comedolytic (break down the comedones). 

Topical antibiotics: Some products containing low-strength antibiotics, like Bacitracin, Neosporin, and Polysporin, are applied on the skin to kill the causative germs. 

In the case of more severe cases, when the OTC products are not working, the patient needs to consult the dermatologist for prescription treatments. The following treatment options are prescribed;

Retinoids: Some products containing high-strength retinoids are prescribed. 

Oral antibiotics: These are used to control bacterial growth and treat infections. 

Chemical and physical procedures: Some chemical and biological procedures like chemical peels to remove the dead skin layer, microdermabrasion to remove the dead skin layer by scrubbing the skin and laser resurfacing to destroy the sebaceous glands in the skin that are producing oils. 

Whiteheads have similarities and differences from other acne lesions; patients need to be aware of these. 

Blackheads: The blackheads have open pores, which leave air inside, causing blackening. In contrast, the closed pores in the whiteheads don't cause such blackening. 

Papules: The papules are more minor and raised bumps that are pinkish to reddish and don't have pus. In contrast to the whiteheads, the papules are inflammatory lesions and cause pain and redness.  

Pustules: The pustules are the inflammatory lesions containing pus. In contrast, the whiteheads are not inflammatory and don't have pus. 

Nodules: Nodules are also inflammatory lesions, and in contrast to whiteheads, they are larger and much more painful.

Cysts: The cysts are pus-filled nodules and are also very painful and more prominent in size than whiteheads.

Most of the whiteheads disappear on their own within seven days. The patient should avoid pooping the lesions as it causes the spread of infection and causes the development of scars. However, it is advisable to visit the doctor when the lesions are found for early treatment and to avoid complications.

Pustules

Pustules are pus-filled acne lesions that develop as bulged-out skin and contain yellowish pus. The pustules develop anywhere on the skin, the common sites being the face, chest and back. The other sites are the hands, feet, legs, arms, groin, buttocks, hairline and scalp. The bumps develop due to the inflammation of the skin due to acne. As the dead cells and oils clog the skin pores, the trapped bacteria feed on the oil and cause infection and production of pus. 

The accumulation of gases and pus cause the skin to bulge out. They have a softer pus-filled centre and reddish surrounding areas. Due to pus-filled pockets (cysts), this form of acne is called cystic acne. Besides the overproduction of sebum and the germs on the skin, some other causes include hormonal changes during puberty, pregnancy, period and menopause, and some diseases like rosacea, psoriasis, folliculitis, eczema, smallpox, and chickenpox also cause the development of pustules.

Pustules are easily identified by their typical appearance. They occur in small bumps with a pus-filled whitish centre and sometimes reddish margins due to inflammation. They are painful, sore and tender to touch due to inflammation. Sometimes, the pustules rupture, releasing their contents onto the surrounding tissues and becoming sores.  Besides these symptoms, some more severe symptoms like warmth, swelling, redness and pain (the four cardinal signs of inflammation) become noticeable. 

Regarding the cause, the clogged pores remain the primary cause of pustules, and dead skin cells and bacteria on the skin play an added role. Due to the breakage of the walls of pores and the filling of pus, the pustule size is larger than the black and whiteheads. 

The pustules often heal on their own without any treatment. However, some home remedies and treatments speed up the recovery process. During the treatment, keeping the surrounding skin clean and oil-free is essential by washing with mild soap and lukewarm water. OTC products, prescription drugs and home remedies are very effective for treatment.

Medical treatment: Various over-the-counter creams, soaps and ointments are available, which contain benzoyl peroxide, salicylic acid, sulphur or azelaic acid in low strengths. The high-strength products are irritant and shouldn't be used without a prescription. If, however, these treatments don't work, treatment with more potent prescription products is required. In more severe cases, oral anti-inflammatory and antibiotic drugs are often recommended to reduce inflammation and infections. Some of these products cause the skin to dry and should be used with moisturizers. 

Home remedies: Some home remedies are very effective in treating and managing the pustules. These include clay masks (contain natural clay that removes dirt and oils from the skin), essential oils (e.g., rosemary oil and tea tree oil, which have anti-inflammatory products that are diluted with career oils) and the aloe Vera gel (a natural substance having anti-inflammatory and antibacterial properties). 

The pustules have various similarities and differences from other acne lesions, e.g., 

Whiteheads: The whiteheads are non-inflammatory lesions and, in contrast to the pustules, are smaller in size, have no pus-filled centre, and are not painful.

Blackheads: The blackheads are also non-inflammatory lesions with open surface pores. They are darker and smaller spots with no central pus-filled cysts or reddish margins. 

Papules: Papules are smaller in size and are reddish or pinkish, and don't contain pus. Like the pustules, they are inflammatory lesions and ultimately convert into pustules as the inflammation continues. 

Nodules: The nodules are also inflammatory lesions but are more raised, painful, and larger than Papules. They develop in more severe forms of acne and take longer to heal. 

Cysts: The cysts are very similar to the Papules in size but have central pus-filled pockets and are very painful. 

The duration of pustules is variable and depends upon many factors like skin type, the severity of the condition and the treatment options used. The mild to moderate pustules heal within a few days to 1-2 weeks, while severe pustules last for months and sometimes leave permanent scars. Habits like picking and squeezing the pustules prolong healing and cause more dangerous and persistent scars.

Cysts

Cysts are sac-like structures which contain a thin or thick liquid or gaseous material. Many cysts develop, and acne cysts are among the most common. The cystic form of acne develops when the infection has penetrated deep into the skin and causes a sizeable pus-filled bump. The bursting of a filled cyst releases its contents causing the further spread of disease. Although most of the people develop acne, cystic acne is more common in people with oily skin. They also occur more commonly in young or older people and women who experience hormonal changes. 

The cystic acne lesions are easily identifiable as they are the largest and the most severe. They are also the deepest skin lesions of acne. They appear as large boils on the skin, as predominantly white and pus-filled bumps surrounded by red skin that are painful and tender to the touch. These lesions are most noticeable on the face. However, they also occur at other sites like arms, back, chest, neck and even behind the ears and on the shoulders. 

Like other acne lesions, the exact cause of cystic acne is not known; however, several predisposing factors like rising androgen levels (male hormones), hormonal changes during pregnancy, menopause and period, the use of some drugs and medications, use of oily skin products, too tight and nonbreathable garments, heavy sweating, living in high humidity environment and some diseases influencing the hormones like polycystic ovarian syndrome etc., have a role. Some other risk factors for cystic acne are younger age (teenage and early twenties), genetic factors and gender (22% of adult women and less than 5% of adult men experience cystic acne, according to the Journal of Clinical and Aesthetic Dermatology). 

Cystic acne looks like skin boils, and some vital signs are red and large lump under the skin, which is often painful and tender to touch and ranges in size from a small-sized pea to a medium-sized dime. Sometimes, the cysts burst, oozing out yellowish-to-whitish pus from the centre and becoming crusted. 

Home remedies and over-the-counter products that work on other types of acne usually don't work perfectly for cystic acne, and prescription medications are required. The commonly prescribed treatments are oral antibiotics to curb infections and inflammations, contraceptive pills to regulate hormone levels, gels, foams, creams and lotions containing retinoids (vitamin A derivatives) to unplug the pores and remove the dead skin cells, preparations containing benzoyl peroxide to kill the bacteria on the skin and control inflammation, oral or injectable steroids to lower the pain and reduce swelling, isotretinoin to inhibit the functions of sebaceous glands and spironolactone to lower the oil production and suppress the levels of androgens. 

Some home remedies like regular hand washing, using oil-clear skin products and exfoliants, avoiding touching or picking the cysts, preventing exposure to sunlight, avoiding the use of harsh chemicals on the skin, reducing the levels of stress, maintaining a healthy lifestyle, including mild exercises, healthy sleep and using foods with the low glycemic index. 

The cystic form of acne is markedly different from other acne types and arguably the most severe form. The significant differences from other types of acne lesions are, 

Appearance: The cystic lesions are large, inflammatory, and red. They contain pus and are often painful to touch. Other acne lesions like white and blackheads are non-inflammatory, are not painful to handle, and don't contain pus. 

Size: The cysts are the most extensive acne lesions with a diameter range of a few millimetres to a few centimetres. The other acne lesions are smaller in size.

Treatment: The cystic lesions are tough and resilient and need prescription medications. Often, oral antibiotics, corticosteroids and topical high-strength retinoids are required. The home remedies and OTC drugs that work with other types are not effective in cystic form. 

Severity: The cystic lesions are more severe than other types, are highly embarrassing and often leave a permanent scar. 

The duration of acne lesions depends upon factors like skin type, disease severity and treatments. A treatment ensures complete recovery in a few weeks, while untreated cases go on for years and often leave permanent scars. It is possible to decrease the duration of by gentle skincare, avoiding touching, rubbing or picking the lesions and timely treatment. When choosing skincare products, select non-comedogenic products that are non-irritating for the skin and prevent irritation.

Nodules

Nodules are inflammatory acne lesions that develop under the skin and are painful and firm to touch. A red bump on the skin is noticeable. Like other acne lesions, the modules develops due to the clogging of a skin pore with dead skin cells and sebum (natural skin oils). In contrast to the blackheads or whiteheads, which develop in most people, a small number of people experience a severe breakout leading to the development of nodules. 

The bacteria (particularly Cutibacterium acnes) found on the skin become trapped inside the clogged pores and cause infection, and the penetration of this infection into the deeper skin layers causes nodules. Some nodules occur alone, while others occur in the form of groups like parches of large modules. Unlike cysts and pustules, the nodules don't have a pus-filled centre and squeezing it causes further aggravation of the problem. 

The acne nodules are easily identified due to their shape and size. They are more minor bumps under the skin. Initially, they are skin coloured, but later on, they take a reddish or pinkish tone due to the inflammation in the surrounding areas. They don't have a central head like many other acne lesions and are hard and painful to touch.

The leading cause is the blockage of skin pores by dead cells and oils-trapping bacteria that cause a deep infection. The risk factors that causes blocked pores and modules are excessive sweating (particularly in people having hyperhidrosis and those using nonbreathable garments), hormonal changes during puberty, pregnancy and periods (cause increased production of oils and thickening of the oils), the use of certain medications like corticosteroids, certain skincare products like creams, lotions that clog the pores, chronic anxiety and stress (causes higher cortisol levels and more sebum and sweat production) and genetic factors.

The essential symptoms of nodular acne are firm nodules that develop anywhere on the face (in males, they appear on the back, chest and face and in females, they grow mainly on the jawline and chin), sensitivity and pain, especially while touching and the development of raised lumps that are either skin coloured or reddish to pinkish due to inflammation. Sometimes, both the cystic and nodular lesions develop simultaneously. 

Home remedies and OTC products are not effective, and nodular acne needs to be treated by a dermatologist. The patients should refrain from popping, squeezing or picking the lesions, as such practices cause the spread of infection and the development of permanent scars. The standard treatment options are;

Topical products: The dermatologist prescribes topical products containing higher strengths of salicylic acid, benzoyl peroxide and retinoids. They are available in foam, gel or cream applied on the skin. 

Oral medications: Dermatologists often recommend oral medications, particularly for severe cases. These include isotretinoin products, contraceptives (to regulate hormone levels), and antibiotics like tetracycline and spironolactone to lower the levels of hormones. The use of antibiotics is guarded as prolonged use cause antibiotic resistance.

Steroids: Corticosteroid injections treat inflammation, swelling and redness and reduce pain. The corticosteroids are mostly injected and sometimes injected into the nodules to lower the swelling and inflammation. 

Nodular acne is different from other types of acne. These differences are,

Whiteheads and blackheads: Whiteheads develop in milder forms of acne and are non-inflammatory lesions. In contrast to the nodules, the whiteheads and blackheads are smaller in size, are not painful and don't cause inflammation. The nodular lesions are also deeper than both of these. 

Pustules and papules: Like nodules, both papules and pustules are painful and inflammatory lesions. However, the bumps (pustules and papules) are smaller than nodules and are less dangerous. Pustules are more prominent and are easily identifiable because they have a pus-filled pocket in the centre. 

Cysts: The nodules are similar to cysts. However, the cysts are large pus-filled pockets and are less firm than the nodules. Cysts are deeper lesions and often cause more severe and permanent scars. 

The nodular lesions are more persistent and hard to recover. The duration depends upon the factors like the treatments used and the disease severity. The time is often between several weeks to several months. However, sometimes, particularly with improper care, the scars develop, which are very hard to go and often persist for a long time.

How to tell what type of acne you have?

Acne is of various types and has different causes, risk factors and treatment options. So it is essential to identify the type of acne for fast response. A close look at the lesions in the mirror and feeling with fingertips (without scratching and picking) helps to understand the kind of acne.

The critical features of each type are mentioned below. 

Blackheads and whiteheads: The whiteheads are flesh-coloured and smaller in size. A thin layer of skin covers the pore, so they are called closed comedones. In the blackheads, the trapped contents are exposed to the air due to pores and become black due to oxidation. Irrespective of the skin type and severity of lesions, these lesions don't cause pain and redness (non-inflammatory). Both of these lesions make the skin slightly bumpy. Blackheads are flatter than whiteheads. The presence of both or either reflects the non-inflammatory type of acne. 

Papules: These are reddish, cystic or solid inflammatory bumps. They don't have pus and occur in clusters on the skin, particularly on the forehead, chin and cheeks. They are firm, tender, and painful when touched, with an average diameter of 2-5mm. The presence of papules means the condition has become inflammatory. 

Pustules: These lesions are similar to papules but have a centrally filled pocket of pus and are less firm and tender to touch, with an equivalent diameter of 2-5mm. In short, as the inflammatory process moves on, the papules convert into pustules.  

Acne mechanica: It is a rare type of acne that develops when some material rubs against the skin, causing friction and entrapment of oils. Athletes mainly experience it, and it causes rough and more minor bumps that are felt more easily than seen. They differ from papules and pustules; if the cause persists, they progress to more severe forms. 

Cysts and nodules: Both cysts and nodules are inflammatory lesions and cause large lesions that penetrate deep into the skin. They are skin coloured or pinkish to reddish, and the degree of redness depends upon the extent of inflammation. Both are tender and painful to touch and leave scars. The cysts vary in size but have a diameter of 5mm or more and have a whitish pus-filled head in the middle. The nodules are slightly smaller than the nodules, are more painful, firmer and feel like knots under the skin. 

What type of acne has pus inside?

The pus is a feature of pimples and cysts. In these types of acne, the trapped bacteria cause infections causing the development of pus. The pus is a thick, greenish or yellowish mixture of dead cells, tissue debris and bacteria. The pustules always have pus, while cysts may or may not have pus. The development of pus in cysts occurs during inflammation. 

When an acne bump builds pus inside it, it becomes an abscess. The development of pus means an inflammatory response has occurred inside the body; the white blood cells have been killed defending the body. The pus accumulates inside a pocket that bulges out as a whitish pocket on the skin. The pus also develops in the cystic form of acne. The only difference between the pustules and the cysts is that the cysts develop due to a much deeper skin infection. It needs to be treated through prescription drugs by the dermatologist, and OTC products and home remedies are not likely to be successful.

What type of acne is mild?

The non-inflammatory types of acne, like blackheads, whiteheads, and occasionally milder inflammatory lesions like papules (low intensity and few), are considered benign and mild. The mild types do not cause inflammation, are less frequent, easily treatable and don't leave persistent scars. Proper skincare routine and early treatment ensures complete recovery and prevention. Prescription drugs are unnecessary, and milder types respond well to OTC products and home remedies.

What type of acne is severe?

Inflammatory acne lesions like papules (occasional), pustules, cysts and nodules are considered more severe forms of acne. The widespread and numerous papules, pustules, nodules and cysts indicate severe acne. These painful acne lesions affect the face, shoulders, back and chest and cause significant physical and emotional stress. 

The OTC products and home remedies are not likely to give any benefit, and these types need to be treated through prescription drugs by the dermatologist using high-strength topical products, oral antibiotics and surgical and physical procedures. These acne lesions often leave dangerous and long-lasting spots and scars. 

What is Acne?

Acne (acne vulgaris) is the inflammatory condition of the hair follicles and sebaceous glands. It is self-limiting but often runs a long and chronic course. The infection is triggered by the blockage of skin pores by the dead skin cells and sebum causing non-inflammatory lesions like whiteheads and blackheads. The subsequent infections of these lesions cause further and more severe lesions like papules, pustules, nodules and cysts. 

It is a prevalent chronic condition triggered by factors like hormonal changes (high levels of androgens), genetic factors, lifestyle and skincare routine, exposure to chemicals and sunlight, use of some medications like lithium, and emotional stress. It is milder in most people, but still, 10-20% of people develop a more severe form, leaving scars. It mainly affects the adolescent boys and girls. The risk of severe acne is higher (20%) in people having a family history of acne and lower (10%) in people having no family history of acne.

During adolescence, the increased levels of testosterone cause increased DHT (dihydrotestosterone) production by the enzyme 5-alpha reductase, which converts testosterone into DHT. The DHT binds to the receptors present on the surface of the sebaceous glands and stimulates them to increase sebum production. It is coupled with increased cellular turnover during adolescence as the body is proliferating and producing new cells at a rapid pace. These factors work together to block the skin pores that trap the debris. When the bacteria on the skin (particularly Cutibacterium acnes) are also trapped or somehow reach the closed pore, they feed on the oil, increase in number and cause infections leading to the development of inflammatory lesions.

What is the common cause of acne?

The leading cause of acne is the blockage of tiny holes in the skin. The sebaceous glands are small glands located under the skin near the surface. These glands are connected to the hair follicles, the roots from which a hair thread emerges. The sebaceous glands secrete sebum, which helps maintain the integrity of the skin by keeping it moist and preventing dryness. However, sometimes particularly during excessive production, the sebum combines with dead skin cells and debris to form a plug. 

These blocked pores develop into pimples. If the skin covers the plugged pores, they develop into whiteheads, while the uncovered pores develop into blackheads. The infection of these blocked pores causes infection and inflammation leading to the development of pimples, pustules, papules and nodules. Many bacteria are present on the skin and don't cause any disease. However, whenever the opportunity arises, they do cause infection. The blocked pores create a favourable environment for bacterial growth. Consequently, infections result. 

Besides this, various other factors trigger acne breakouts. Some common triggers of acne are consuming foods having a high glycemic index, smoking (mainly in adults), the use of some medications like steroids and lithium (used for mental disorders like bipolar disorder and depression), use of antiepileptic drugs and the use of some cosmetic products (it is not a significant cause as these products are mostly tested for safety, and the consumers prefer non-comedogenic products). 

The other reasons include hormonal changes, genetic factors and gender. Due to the widespread nature of the issue, many misconceptions and myths about its causes and treatment need to be addressed.

Hormones: The levels of some hormones like oestrogen and testosterone begin to increase with the start of teenage and are significant factors responsible for teenage acne. The primary influence of these hormones is on the sexual organs, but they also influence other organs and cells like sebaceous glands, which produce more and more sebum. 

Genetics: Acne has a genetic predisposition; if the parents have acne, the children are likely to experience acne. Genetic studies have found that the heritability of acne is up to 80%. It means if both parents had acne in their youth, there is an 80% likelihood that the children will likely experience severe forms of acne in adulthood. Similarly, adult acne also has a genetic predisposition, and the children of parents experiencing it are more likely to experience it than others.  

Gender: Gender also influences the risk of acne, and women are more likely to develop adult acne than men. The primary cause of adult acne is the changes in hormones. Women experience more hormonal changes during periods, pregnancy (more commonly in the initial and final three months of pregnancy), and the presence of some diseases that influence hormones like polycystic ovarian syndrome (PCOS) etc. According to a study published by the Journal of Clinical Aesthetic Dermatology in 2017, 44% of women and 40% of men reported experiencing acne. The study involved a random sample of 749 people.

Major triggers: Besides these primary causes, acne is triggered by various other triggers like the use of some cosmetic products (that are not labelled as 'non-comedogenic'), certain medications, hormonal therapy, certain high-energy and high-energy and high-fat foods etc. The exposure to these factors triggers breakouts in the susceptible people. 

What are the common symptoms of acne?

The signs and symptoms start once a pore is plugged and cause visible spots on the face. As the condition progress, the non-inflammatory lesions start to get an infection and become inflammatory. Severe symptoms and scars are observed in the cystic form of acne. The symptoms of acne are categorized as common symptoms, non-inflammatory and inflammatory acne and rare symptoms.  

Common symptoms: The pimples are the primary signs of acne and are easily seen and felt by the patient or repotted by the near ones. Most people experience both non-inflammatory and inflammatory lesions at the same time. These blemishes appear on the face, chest, back, shoulder, buttock, neck and other areas but become more visible on the face. 

Signs of non-inflammatory lesions: The non-inflammatory acne (also known as comedones acne) causes mild blemishes that are not painful and red. The symptoms include skin bumps leading to rough and uneven skin due to blocked skin pores (comedones). The blackheads, milia, micro comedones (the comedones too small to be seen but can be felt) and whiteheads are frequently seen. Even if the lesions are not clearly visible, the rough, sandpaper-like appearance of the skin is easy to feel. 

The symptoms of inflammatory acne: Inflammatory acne causes swollen, reddish and painful pimples, and just free blemishes on the skin are easily felt. The inflammation causes more severe breakouts and deep lesions. Some of these lesions ooze out pus, burst and form crusts and scabs. The papules cause raised and reddish bumps a few millimetres to 10mm in size. In contrast, the bumps cause a reddish and inflamed lesion with a white head in the centre. The cysts and nodules are larger and penetrate the deeper skin layers and leave scars after healing. 

Rare symptoms of acne: Cystic acne is a less common but severe form of acne. People having nodulocystic acne experience nodules and cysts with variable severity. The cysts are painful, fluid-filled, soft lesions that develop under the skin surface. The nodules are larger-sized, painful and hard lesions that also develop under the skin and are harder to treat. A study published by the Journal of Investigative Dermatology in 2009 noted that the risk of severe acne in school-going children was 14-19.9%. 

Complications of acne: Sometimes, acne causes severe complications that become the cause of concern. These complications need immediate treatment and leave permanent scars if not addressed timely and correctly. These include;

Excoriated acne: This complication develops as a person picks or scratches the actual or imagined acne lesions and causes wounds. The issue is more common in women and leads to compulsive/ obsessive excoriation disorder. Constant picking and squeezing causes more severe red bumps, open wounds, sores, and scratches, ultimately leading to crusting and scabbing. The skin infections paves the way for more severe skin diseases. 

Hyperpigmentation: Hyperpigmentation refers to the discoloured skin and dark spots left behind by the healing acne lesions. It is widespread, and many people with acne develop it. According to a recent study by Al-Qarqaz and his colleagues in 2021, post-acne hyperpigmentation is experienced by 80% of patients. The extent of the problem is, however, variable. These are, however, not true scars and fade away with time.

Scarring: The inflammatory acne lesions leave various scars like an ice pick scars that are narrow and long impressions in the skin and pitted and depressed scars that have a central depression. In some people, acne causes raised and hypertrophic scars. These scars are difficult to treat and last much longer. Sometimes, the acne scars don’t go away even with treatments and need surgical intervention.  

Acne and diabetes and pregnancy: People with diabetes have a lower resistance to soft tissue and skin infections and, consequently, have more risk of inflammatory acne. Increased levels of insulin in the diabetic cause increased levels of androgens that stimulate sebum production. Likewise, hormonal changes cause more risk and severity of acne lesions in pregnant women. The treatment choice during pregnancy should be careful as some medications cross the planets leading to congenital disabilities, stillbirth and miscarriage. 

Psychological symptoms: Psychologists have reported that acne often causes damage to the self-esteem and self-confidence of patients with acne. These effects are widespread during early adulthood and teenage and severely affect the quality of life. The lower self-esteem and self-image hinder career and studies. As such, people with acne are likely reluctant to speak in class, make new friends, get a part-time job and perform poorly in meetings. It also influences relationships. Some teens also experience symptoms of severe depression, even leading to thoughts of self-injury and suicide. 

How to treat acne at home?

The at-home treatments involve the use of natural herbal medicines and herbal extracts. The choice of some home remedies, like topical applications, should be discussed with the doctor, or at least a skin patch test should be done to see that it doesn't cause allergic reactions. The following home remedies are proven and worth trying. 

Tea tree oil: It is a natural anti-inflammatory and antibacterial product that kills the causative bacteria (Cutibacterium acnes) and curbs inflammation by reducing swelling and redness. It is applied directly on the skin by adding to other essential oils, creams and gels, and studies have found it useful. A 12-week use of tea tree oil gel (200mg/g) reduced the mean lesion count from 23.7 to 10.7, according to a pilot study conducted by Harsimran Kaur and colleagues in 2017. 

Aloe Vera: Aloe Vera has zinc, amino acids, and sugars, making it an excellent skin moisturizer. It is helpful for people who experience skin dryness after using anti-acne treatments, and its anti-inflammatory and antibacterial properties provide additional benefits. A thin layer is applied directly on the affected skin twice a day, once or twice a day. 

A study by Zhong and his colleagues in 2021 found that a two-month use of the aloe vera gel caused a significant reduction in the hyperpigmentation lesions, number of papules and improved blood circulation in the skin.

Coconut oil: Coconut oil has a moisturizing and soothing effect and antibacterial and anti-inflammatory properties. It speeds up the natural healing process of the skin. Pure and virgin coconut oil is applied directly on the skin. It should also be added to the common foods. 

Rosemary extract: Rosemary extract has many chemicals like caffeic acid, rosmarinic acid, ursolic acid, carnosic acid, and carnosol that have antibacterial, anti-inflammatory and antioxidant properties. The research has found that rosemary extract helps treat inflammatory lesions of acne. 

Green tea: Green tea is a treasure of catechins, the famous polyphenol antioxidants which prevent skin damage caused by the oxygen-free radicals in the body. Some other compounds in green tea like EGCG lower sebum production and inflammation and keep the population of bacteria on the skin under check. Green tea is applied directly on the skin or used as a drink regularly, and several studies have confirmed its usefulness.

Zinc: Zinc has anti-inflammatory properties and is known to lower the signs of inflammation of acne lesions. Various studies have found it helpful, and some have noted that effects are more pronounced when applied directly on the skin instead of oral use, as oral use reduces the amount of zinc that reaches the skin. It is available both as oral supplements and in the form of topical preparations. 

Honey: Honey is among the most common traditional treatments used for almost every disease due to its anti-inflammatory and antioxidant properties. Applying it soothes the skin and unclogs the skin's pores. However, no large-scale study has confirmed its usefulness for acne. 

Besides these preparations, some lifestyle changes like avoiding rubbing, squeezing and unnecessary touching of the skin, particularly inflamed skin having acne lesions (this practice introduces new bacteria into the lesions and causes further spread of infection), using the skincare products according to the needs and skin types, using oil-free and non-comedogenic skincare products, staying adequately hydrated and reducing the regular stresses by spending time with family and friends, taking proper sleep, eating a well-balanced diet, spending some time on exercise regularly, avoid smoking, use of recreational drugs and alcohol and practising mindfulness meditation exercises.

Is it recommended to treat acne at home?

Yes, treating mild to moderate types of acne at home is recommended as it is very effective and safe. Home remedies treat mild cases and prevent them from progressing into more severe and clinical forms. It is also an economical option. 

Many over-the-counter skincare products and home remedies, like eating a well-balanced and healthy life, avoiding unnecessary picking and squeezing the lesions, reducing stress levels and keeping the skin dry and clean, help treat mild acne. However, it should be remembered that severe and inflammatory types of acne should be treated by a dermatologist as soon as possible. It is essential because these lesions are not likely to respond to home remedies and time wasted on home remedies causes’ disease progression and more severe symptoms.

Is having acne normal?

Yes, experiencing acne is perfectly normal. Acne is experienced by millions of people worldwide, particularly the young and adolescents. It is due to the issues associated with the management of skin care. So, although acne is the cause of frustration and stress and blemishes the cosmetic beauty, it is not a medical emergency and is easily treatable and manageable by timely intervention. 

Although almost everyone experiences acne, not everyone has the same type and severity, and patients must report to the doctor once the signs of inflammatory lesions appear. It helps to avoid more severe acne lesions that are difficult to treat. 

 Is acne also called Pimple? 

Yes, the term ‘pimple’ refers to the acne breakout. Pimples are skin blemishes, the others being blackheads, whiteheads, nodules and cysts. So, pimples characterized by the development of raised and smaller-sized bumps are one of many acne lesions. But, due to their widespread nature and lack of public knowledge about the other lesions, it is common to refer to acne as just the 'pimples'.  

What is the difference between Acne and Pimple?

Acne and pimples are different terms but are often used interchangeably. However, they have a significant technical difference. The difference between acne and pimples is like the difference between rickets and bone weakness. It means acne is the primary cause, and pimples are among its many clinical manifestations. Acne develops due to the clogging of skin pores by dead skin cells and sebum, further complicated by secondary bacterial infections leading to many signs. Pimples are among the clinical manifestations of acne. So, pimples are just one among many acne lesions and not all forms of acne cause pimples. Understanding different types of acne lesions is very important for proper treatment.