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Acne: Causes, General Care, and Treatment

Sherry Haynes is currently pursuing a PharmD degree and has experience in both the clinical and management sides of pharmacy.

Acne is a disorder of the pilosebaceous unit, which is made up of the sebaceous gland, hair, and hair follicle. Acne is characterised by comedones, papules, pustules, cysts, and scars.

The pilosebaceous follicles are present in the highest concentration in the face, upper chest, back, and behind the ears. These areas are where acne lesions are most common.


  • 85% of people between 12-23 years of age will have some acne.
  • It persists into the 20s in 64% of people and into the 40s in 45% of people.
  • The peak age for severity of acne in girls is 16 and 17 years, while in boys, it is 17-19 years.


Sebaceous glands associated with hair lie at an obtuse angle between the follicle and the epidermis. The glands discharge sebum into the upper part of the hair follicle where it lubricates and waterproofs the skin to protect it from drying.

What Causes Acne?

Many factors can combine to cause acne.

  1. Overproduction of sebum:
    • The sebaceous gland increases in size and produces more than normal amount of sebum.
  2. Increased sensitivity to hormones:
    • Androgens are the main stimulators of sebum excretion.
    • In acne, the sebaceous glands become more sensitive, responding excessively to normal levels of these hormones.
  3. Clogged pores:
    • Genetic and environmental factors (e.g. some cosmetics) cause the epithelium to overgrow the follicular surface and partially close the pore.
    • The follicles then retain sebum that has high concentrations of bacteria and free fatty acids. Rupture of these follicles leads to tissue damage and inflammation.
  4. Genetic:
    • The heritability of acne is almost 80 percent in the first-degree relatives.
  5. Propionibacterium acnes:
    • Propionibacterium acnes are the bacteria that live in the hair follicles of every human. These bacteria are found in higher numbers in people with acne.
    • The bacteria colonize the pilosebaceous ducts and break down triglycerides releasing free fatty acids. This will make the epithelium secrete cytokines that cause inflammation.
    • Neutrophils—a type of white blood cell released as a result of the inflammation—release lysosomal enzymes causing follicular rupture.
    • The contents inside the follicles are released, resulting in foreign body reactions that further the inflammation reaction.
  6. Inflammation due to a sudden surge of hormones or ingredients in cosmetics:
    • When inflammation occurs in the follicles, the follicle wall becomes swollen, minimizing aeration of the bottom portion, where P. acnes resides. This is how sudden papules occur.

Classification of Acne

  1. Comedonal acne
    1. In this type of acne, comedones are first formed which then progress into inflammatory or non-inflammatory acne after the follicle impaction.
    2. Comedonal acne takes weeks or months to develop.
  2. Inflammatory acne:
    1. Inflammatory acne is caused by inflammation inside the follicle. Flares of papules may develop even overnight and at any age.
    2. This is caused by caused by a sudden increase in the sebum production that is generally triggered by sudden hormonal flares.
    3. Certain topically applied cosmetics, skin care products, or drugs may also contain ingredients that cause inflammation.
    4. Sometimes, inflammatory acne will also have open and closed comedones with it.

The Progression of Lesion Development

  1. Closed Comedo (Whitehead)
    • Blockage of a pilosebaceous follicle by epithelial cells results in a closed comedo. It develops to form either a papule or a black head.
    • Because the follicles are closed, they do not permit entry of oxygen. This, combined with the large amount of solidified sebum that forms—promotes the growth and activity of P. acnes.
  2. Open Comedo (Blackhead)
    • A blackhead is a sebaceous follicle with a dilated follicle opening. The follicle is filled with dead cells imbedded in a semi-hardened mass of sebum.
    • The dilated opening allows the oxygen to enter, inhibiting the growth of P. acnes. Thus, a blackhead rarely progress into inflammatory lesions.
    • Because oxygen is present, the melanin pigment in the follicle gets oxidised and makes the pore appear black. The dark colour of a blackhead has nothing to do with dirt.
  3. Papule
    • If a closed comedo becomes larger and more packed due to the buildup of debris and inflammation from the metabolic activity of the bacteria, a papule forms.
    • P. acnes produces enzymes such as elastase that weakens the follicle wall eventually rupturing it. The immune system responds to this rupture by sending white blood cells (WBCs).
    • The WBCs travel with the blood to the site of the rupture. At this point, the lesion turns red due to blood engulfing the ruptured follicle.
    • Papules are red and feel sore due to the pressure of inflammation and the skin pressing on pain nerve endings.
  4. Pustule
    • When WBCs enter the ruptured follicle to attack the bacteria, many of them are killed in the process.
    • Furthermore, many enzymatic processes takes place to reduce the inflammation, remove debris and bacteria, and regenerate the follicle.
    • All these processes result in liquefication of the contents of the follicle. The liquefied contents and WBCs make up the pus, and the papule is now called a pustule.
  5. Nodule
    • A nodule is a lesion similar to a papule but much deeper in the dermis—so deep that it even reaches the subcutaneous layer of the skin.
    • Nodules often involve multiple follicles that break down to form a large pocket of infection.
  6. Cyst
    • A cyst is similar to a nodule but with an epithelial lining and largescale inflammation.
    • The accumulation of massive amounts of WBCs often forms boil-like lesions that can eventually rupture.
    • Cysts are responsible for most of the acne scars. However, cysts can be treated by a dermatologist who will inject the lesion with cortisone to reduce the inflammation and cause it to go away with minimal damage.

What Causes Acne Scars?

Acne Scarring

Now that the inflammation has taken place the skin tries to deal with it and reduce the infection. Here are the types of scars that can form in the process:

  1. Hypotrophic Scars (Pock or Ice Pick Scars)
    • The inflammatory process in which WBCs try to clean and rescue a ruptured follicle involves enzymes that destroy the collagen in the skin.
    • These enzymes and other immune reactions continue to dissolve the skin tissue, causing depressed scars medically termed as hypotrophic scars.
  2. Hypertrophic Scars
    • Eventually, the immune system activates fibroblasts, the cells that produce collagen to repair damaged tissue (scar tissue).
    • Attempting to repair and replace the damaged tissue, the collagen is produced in abundance and results in a buildup of excess collagen. This appears as raised scars medically termed as hypertrophic scars.
    • Most hypertrophic scars resolve with time as the skin enzymes dissolve some of the excess collagen.
  3. Keloid Scars
    • Keloid scars are a very rare type of scar formed when too much scar tissue is formed.

What Exacerbates Acne?

  1. Drugs and Hormones:
    • Many medicines can make acne worse or induce acneiform eruptions:
      • Progesterone-containing contraceptives like intramuscular medroxyprogesterone acetate or norethisterone enanthate
      • Implantable progesterone (etonogestrel) pellets
      • Progesterone-releasing intra-uterine devices
      • Combination oral contraceptives that contain levonorgestrel as progestogen
      • Oral and topical corticosteroids
      • Anabolic steroids
      • Vitamin B12 (especially the high dose, intramuscular products)
      • Lithium
      • Diphenylhydantoin
  2. Stress:
    • Stress does not cause acne but may exacerbate it by promoting systemic inflammation.
  3. Touching the Face:
    • Scrubbing the face, cradling the chin with your hand, or picking at the pimples can cause the rupture of sebum-filled follicles. This will produce inflammatory reactions.
  4. Cosmetics:
    • Certain ingredients—like isopropyl myristate—in the cosmetics are comedogenic.
    • Products with lanolins, petroleum bases, or cocoa butter, such as cleansing creams, suntan oils, and heavy foundations, should be avoided.
    • Nowadays, most cosmetics do not have comedogenic ingredients.
  5. Menstrual Cycle:
    • Acne may flare up in some women during the premenstrual phase. Fluctuations in the level of progesterone are probably the cause.
  6. Too Much Moisturizer:
    • Excess moisture on the skin leads to keratin hydration, swelling, and a decrease in pore size, resulting in duct obstruction.
    • Overhydrating the skin with unnecessary moisturizing creams and masks may worsen the condition.
  7. UV Rays
    • Sunlight and artificial UV (tanning beds) sometimes helps dry out acne and promote new skin growth, both it can also exacerbate acne.
  8. Diet:
    • Many people think that their acne worsens when they eat certain types of foods such as chocolate, meat, or diary products. So far, no studies have found a strong connection.
    • However, some recent studies suggest low glycaemic diets for acne patients.
    • If someone thinks their acne gets worse with something, they are encouraged to avoid it.
Benzoyl peroxide is the most widely available and most commonly used acne treatment.

Benzoyl peroxide is the most widely available and most commonly used acne treatment.

How Do You Treat Acne?

General Care

  • Avoid anything that seems to worsen the acne.
  • Most people with acne have oily skin. Gentle cleansing two to three times a day helps remove excess oil and sebum.
  • Do not scrub the acne. Scrubbing won’t clear away the acne scars. It actually worsens the acne by disrupting the repair process and leads to more inflammation.
  • Use only mild facial soaps to clean the skin.
  • For mild comedonal acne, using cleansers with pumice, polyethylene, or aluminium oxide might be beneficial.

Over-the-Counter (OTC) Medicines

Self-treatment with OTC agents is appropriate only for patients with non-inflammatory, grade-1 acne. If you are not sure about the grade and severity of your acne, it is best to consult your doctor or pharmacist before you attempt treatment.

  1. Benzoyl peroxide:
    • It is considered as the most effective topical agent for acne, and many OTC acne products have it.
    • It is initially only applied at night but can be used twice daily if there is no dryness and irritation.
  2. Salicylic acid:
    • It is used to promote the absorption of other acne products.
  3. Sulfur combined with resorcinol or resorcinol monoacetate:
    • It is keratolytic and has antibacterial action.
    • However, with continued use, it may actually cause acne.
    • It also has an offensive odour and color.

Prescription Medicines

Your dermatologist may prescribe one or more of these medicines for chronic or severe cases of acne. Never use prescription medicines that weren't prescribed to you, even if someone says it worked well for them.

Topical agents (Creams, gels, emollients)

  1. Vitamin A (Retinol) analogues:
    • Retinol is effective against comedones.
    • Skin irritation and photosensitivity (sensitivity to sunlight) are often there with these agents.
    • Pregnant women should not use retinoid-containing agents.
  2. Tretinoin (Retin-A):
    • Tretinoin is used to clear comedones and prevents the formation of new ones.
    • It is most effective topical medicine for comedonal and non-inflammatory acne.
    • For inflammatory acne, it is usually prescribed in combination with antibiotics or benzoyl peroxides.
    • Side Effects: Irritation, redness, peeling, and increased risk of sunburn.
    • There may be an initial flare up of acne at 2-3 weeks, but by 8 weeks, patients will see significant improvement.
    • Because of it increases photosensitivity, it is usually applied at night.
  3. Tazarotene:
    • Tazarotene is prescribed for mild to moderate facial acne.
    • It is applied once daily in the evening.
    • Adverse effects related to dosage may include itching, burning, and redness.
  4. Azelaic acid:
    • Azelaic acid works by killing the P. acnes bacteria and reducing keratin production to discourage further infection of the pores.
  5. Topical Antibiotics:
    • Clindamycin, erythromycin, and sulfacetamide are commonly prescribed in combination with benzoyl peroxide and topical retinoids to increase the effectiveness and reduce the resistance of the P. acnes bacteria.
  6. Dapsone:
    • Dapsone is a fairly new antibiotic agent used to treat acne.
    • It is unsafe in those with a G6P dehydrogenase deficiency or certain blood disorders.
  7. Cosmetic Camouflage:
    • This isn't a prescription but can be a quick fix to conceal acne and acne scars.
    • Strategically blend make-up with your natural skin tone to cover up pimples and obscure post-inflammatory pigmentation (redness or scarring).

Systemic and Whole-Body Acne Treatments

  1. Oral Antibiotics
    • Tetracyclines:
      • Tetracyclines are not prescribed for use in pregnant women or children under 9 years of age.
      • They should be taken on an empty stomach, at least one hour before food.
    • Minocycline:
      1. Minocycline is a tetracycline antibiotic, but it is not the first-choice prescription because of the risk of causing lupus-like symptoms and pigmentation.
      2. Doxycycline is a cheaper alternative to minocycline but may have a higher frequency of phototoxic skin reactions, among other side effects.
    • Erythromycin:
      • Erythromycin is a macrolide antibiotic. It inhibits protein synthesis in bacteria, stopping the bacteria from growing.
      • It is also not a first-choice, but it may be prescribed to women who are or will become pregnant.
  2. Hormone Therapy (HT)
    • HT is very effective for women, even for those with normal serum androgen levels.
    • HT tends to work best in women who have persistent acne around the chin that flare during their menstruation.
    • Hormone therapy for acne may consist of:
      • A combination of antiandrogen agents and estrogen
      • Combined oral contraceptives
      • Spironolactone:
        • Spironolactone blocks androgen receptors and reduces sebum production.
        • It may cause increased potassium levels in the body and is avoided in pregnancy.

Physical Treatments

  1. Chemical peel:
    • Chemical peels help comedo plug extrusion (blackhead removal). These are a good adjunct to medical treatment.
    • The chemicals used are lipophilic substances, such as beta-hydroxy acids (e.g. salicylic acid), that preferentially target lipid-filled follicles.
  2. Drainage and Extraction:
    • This is done to remove large comedones, especially after using oral isotretinoin.
    • A syringe needle or blade and a comedo extractor help in the rapid removal of comedones. This procedure is performed by a dermatologist and is generally used along with retinoid medicines.
  3. Incision:
    • Cysts are incised and removed with or without using anaesthetic.
  4. Light or Laser Treatment:
    • This is an alternative therapy for patients who cannot use the medicines.
    • Blue light shone on the pimple reduces the number of P. acnes by photoactivation of porphyrins produced by the bacteria. This is becoming a popular therapy and may be used in combination with other medicines.
    • Intense, pulsed light (IPL) and photodynamic therapy are other options.
    • However, because photodynamic therapy has not proved more useful than retinoid agents and also has some side effects, its use is limited.

Frequently Asked Questions

  1. Can acne be treated permanently?

    • There is no permanent cure for acne. Isotretinoin—a medicine which requires the consideration of many factors, side-effects, and tests—is the most effective treatment that can cause long-term remission of acne. As much as isotretinoin is effective, it is known for causing teratogenicity, liver enzyme abnormalities, and dyslipidemia.
    • There are many effective treatments and procedures performed by dermatologists to treat acne. Your doctor will determine which treatment suits your acne type and your acne may clear after the course. However, you may need to take the medicines even after the acne is cleared to prevent new breakouts. Consult your doctor before beginning any type of treatment so that you use the safest and most effective treatment.
  2. Can acne scars/pits/marks be healed?
    • Yes, acne scars can be healed by procedures such as dermabrasion, skin resurfacing, and using dermal fillers.
  3. Are acne and pimples the same?
    • Pustules (acne lesion with pus in them) are also known as pimples. However, "pimple" is a general term used non-specifically for all types of lesions of acne.
  4. Can acne be cured naturally?
    • There are many studies that have shown the effectiveness natural remedies like aloe vera and tea tree oil in treating acne.
    • However, none of them target all the factors involved in causing acne, and therefore, you cannot tell if a particular remedy will work for you. This requires trial and error.
    • In addition, just because it is natural, it doesn't mean there are no side effects. As with prescription medication, consult your doctor before trying any alternative remedy or treatment.
  5. Can acne be a symptom of pregnancy?
    • Acne may occur during pregnancy, usually in the third trimester due to increased sebaceous function.
  6. Did acne exist in the past?
    • Ancient Greek philosophers like Aristotle and Hippocrates recognised acne. An article named “Section of the history of medicine” mentions this. Also, it is said that the tropical acne was a significant problem during World War 2.
  7. What are acneiform eruptions?
    • Acneiform eruptions are a group of disorders that have papules and pustules resembling that of acne vulgaris. Acneiform eruptions can occur in both men and women at any age.
  8. What is the difference between acneiform eruptions and acne vulgaris?
    • Acne vulgaris has comedones while acneiform eruptions do not.
  9. Is acne caused by dandruff?
    • Dandruff does not cause acne, but both conditions are closely related.
    • The scalp is covered with pilosebaceous units. Sebum secretion is controlled by sebaceous glands activity which is strongly related to scalp flaking disorders. Sebum, when secreted by the glands, comes out of the pores on the scalp. It is an important food source for fungi and bacteria living on the scalp. When acted upon by fungi, it can cause irritation that, in turn, cause dead, dry skin (dandruff) to build up. When the flakes cause inflammation, it is called seborrheic dermatitis. Excess sebum also leads to development of acne because of the blockage of sebaceous follicle.
  10. Should acne be squeezed?
    • Squeezing irritates the skin and makes it prone to inflammation. Squeezing of blackheads and pustules may actually produce scars.
  11. Should acne be moisturised?
    • According to acne management guidelines, acne does not require any moisturising unless there is another pathology present.
  12. When does acne medication not work?
    • Many reasons may lead to failure of treatment, such as antibiotic resistance in P. acnes, Gram-negative folliculitis, endocrine abnormality, severe oiliness, high-glycaemic diet, taking oral isotretinoin on an empty stomach, the retinoid form is not suitable for your skin type or environmental condition (emollients and creams are preferred for sensitive skin, while gels are preferred for oily skin), applying medicine to only the spots (not surrounding areas).
  13. Why acne comes on face and back?
    • Pilosebaceous follicles are present in high concentrations in these areas and will always be susceptible to clogs and infections.
  14. Can coffee cause acne?
    • There is not sufficient data to suggest caffeine as a cause of acne.
  15. Can acne scars heal on their own?
    • Hypertrophic scars (red, raised scars) are reduced over time by skin enzymes that dissolve excess collagen.
  16. Does acne spread?
    • No, acne is not contagious.
  17. Does acne itch?
    • Large, tender lesions may cause itching.
  18. I have a wedding to attend. Is there a way to get rid of acne in short time?
    • Using prednisolone prescribed by a doctor may rapidly improve acne for important events.
  19. Can acne cause a fever?
    • A fever is rarely a symptom of acne, even with large lesions.
  20. Is it important to treat acne?
    • Sometimes, not treating acne may result in permanent scars.
  21. When will my acne resolve?
    • If you are a teenage boy, you may expect your acne to clear by the age of 20-25 years. For girls, the news is not so good—it may take longer than for boys.
    • Most cases of adult-onset acne were found in women—5% of women and 3% of men had acne even in their late 40s.


This article is meant for informational purposes only. It is not intended as a substitute for medical advice and should not be used to self-prescribe medicines. Always consult your doctor to identify the type and grade of your acne and receive the correct treatment.


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This content is accurate and true to the best of the author’s knowledge and does not substitute for diagnosis, prognosis, treatment, prescription, and/or dietary advice from a licensed health professional. Drugs, supplements, and natural remedies may have dangerous side effects. If pregnant or nursing, consult with a qualified provider on an individual basis. Seek immediate help if you are experiencing a medical emergency.

© 2018 Sherry Haynes


Admirer on December 15, 2019:

Thats quite interesting and useful information!