Medical condition
Acne
Acne is a chronic inflammatory disease of the pilosebaceous unit, the skin unit formed by a hair and its sebaceous gland. It manifests as various lesions on the face, back, chest, and shoulders, where sebaceous glands are most numerous and active. Although often associated with adolescence, acne can begin or persist into adulthood, particularly in women. It affects approximately 85 % of adolescents to varying degrees, and up to 25 % of adult women aged 25 to 40 experience some form of persistent or late-onset acne. Beyond the physical impact, acne can significantly affect quality of life, self-esteem, and psychological health.
What are the mechanisms that cause acne?
Acne results from the interaction of four main mechanisms that combine and amplify each other:
| Mechanism | Description |
|---|---|
| Hypersweating | Excessive production of sebum by the sebaceous glands, primarily stimulated by androgens (testosterone, DHEA). Excess sebum obstructs the follicular canal and creates an environment favorable for bacterial proliferation. |
| Infundibular hyperkeratosis | Abnormality in the shedding of cells from the wall of the pilosebaceous follicle, which accumulate and form a keratinized plug obstructing the follicular ostium: the comedone |
| Bacterial colonization | Proliferation of Cutibacterium acnes (formerly Propionibacterium acnes), an anaerobic bacterium naturally present on the skin, in the blocked follicle. It breaks down the triglycerides in sebum into irritating free fatty acids and triggers an inflammatory response. |
| Inflammation | Local immune response triggered by C. acnes and free fatty acids, leading to the formation of papules, pustules, nodules, and cysts depending on the intensity of the reaction |
What are the different types of acne lesions?
Acne lesions are divided into two main categories: non-inflammatory (retentional) lesions and inflammatory lesions.
| Type of lesion | Clinical description | Category |
|---|---|---|
| Closed comedone (whitehead or microcyst) | Cystic acne with a closed ostium, forming a small, non-inflamed whitish or flesh-colored bump under the skin | Retentional |
| Open comedone (blackhead) | Obstructed follicle with an open ostium: the kerato-sebaceous material oxidizes on contact with air and turns black (the black color is not due to dirt). | Retentional |
| Papule | Red, firm, painful to the touch elevation, less than 5 mm in diameter, without visible purulent collection | Inflammatory |
| Pustule | Lesion similar to a papule but containing visible pus on the surface, surrounded by an erythematous halo. | Inflammatory |
| Nodule | Deep, firm, painful lesion, over 5 mm in diameter, resulting from intense inflammation of the follicle. May leave scars | Severe inflammation |
| Cyst | Fluctuating and painful collection, well-demarcated, filled with pus. High risk of scarring in the absence of appropriate treatment. | Severe inflammation |
What are the aggravating factors?
- Hormonal fluctuations: puberty, menstrual cycle, pregnancy, polycystic ovary syndrome (PCOS), starting or stopping hormonal contraception
- High glycemic index diet: Some studies suggest a link between the consumption of refined sugars and dairy products (especially skim milk) and the worsening of acne, by stimulating IGF-1 and androgens.
- Stress: stimulates the production of cortisol and adrenal androgens, increasing sebum production
- Mechanical friction and pressure: wearing of helmets, straps, masks, or repeated rubbing on skin (acne mechanica)
- Comedogenic cosmetics and hair products: mineral oils, certain occlusive emollients
- Certain medications: corticosteroids, lithium, anti-epileptic drugs, anabolic steroids, certain progestin-only contraceptives
- Smoking: associated with a specific type of retention acne called smoker's acne, often with little inflammation but persistent.
- Wound manipulation: promotes secondary infection, inflammation, and scar formation.
ℹ️
Contrary to a widespread misconception, acne is not caused by a lack of hygiene. Cleansing too often or too aggressively can, on the contrary, damage the skin barrier, cause reactive dryness, and worsen inflammation. A gentle, non-comedogenic cleanser, used twice a day, is sufficient.
How is acne classified by severity?
| Grade | Features | Standard first-line treatment |
|---|---|---|
| Light | Predominant open and closed comedones, a few papules and pustules, without nodules or cysts | Topical treatments: topical retinoids, benzoyl peroxide, azelaic acid |
| Moderate | Mixture of retention and inflammatory lesions (papules, pustules) in larger numbers, possible trunk involvement | Combined topical, topical antibiotics (clindamycin), sometimes oral antibiotics |
| Severe | Numerous nodules and cysts, extensive involvement of the face and trunk, high risk of scarring | Oral isotretinoin, oral antibiotics, anti-androgenic hormonal contraceptives in women |
| Very severe (conglobata, fulminans) | Rare and severe forms with massive lesions, confluent abscesses, sometimes with systemic signs (fever, joint pain) | Urgent specialized dermatological care, isotretinoin at adapted doses |
What treatments are available?
Acne treatment is tailored to the severity, lesion topography, hormonal profile, and patient history. A combination of topical and systemic treatments is often necessary for moderate to severe forms:
| Treatment | Mechanism and indications | Important remarks |
|---|---|---|
| Topical retinoids (tretinoin, adapalene, tazarotene) | Normalizes follicular shedding, reduces blackheads and inflammation. Maintenance treatment for retention and mixed acne | Frequent initial irritation, photosensitivity: apply in the evening, sun protection is essential |
| Benzoyl peroxide | Bactericidal against C. acnes, mildly keratolytic. Effective on mild to moderate inflammatory lesions. | Can bleach textiles. No bacterial resistance reported, unlike antibiotics |
| Azelaic acid | Anti-inflammatory, antibacterial, and mildly keratolytic. Also effective against post-acne hyperpigmentation. | Well tolerated, usable during pregnancy, suitable for sensitive skin and dark phototypes |
| Topical antibiotics (clindamycin) | Reduces colonization by C. acnes and inflammation. Always associated with benzoyl peroxide to limit bacterial resistance. | Never use as monotherapy for prolonged periods due to the risk of resistance |
| Oral antibiotics (doxycycline, lymecycline) | Indicated in moderate to severe inflammatory forms or in case of trunk involvement. Duration limited to a maximum of 3 months. | Always associated with a topical. Risk of photosensitization with tetracyclines |
| Anti-androgenic hormonal contraceptives | Combined estrogen-progestogen pills with anti-androgenic progestogen (cyproterone acetate, drospirenone). Effective in women with a hormonal component. | 3 to 6 month efficacy period, additional benefit for dysmenorrhea and PCOS |
| Oral isotretinoin (Accutane, generics) | Systemic retinoid acting on acne's four mechanisms. Standard treatment for severe, nodulocystic, or resistant forms. | Teratogenic: mandatory contraception for women. Close medical follow-up required (liver and lipid tests, psychological monitoring) |
What are the possible complications?
- Atrophic scars (indented, cup-shaped, or ice-pick): permanent sequelae of untreated or poorly treated nodulocystic forms
- Hypertrophic scars and keloids: more frequent on the trunk and in certain phototypes
- Post-inflammatory hyperpigmentation: brown macules persisting for several months after lesion healing, particularly visible on darker skin tones
- Psychological impact: social anxiety, depression, low self-esteem, isolation. Severe acne is associated with a psychosocial impact comparable to chronic illnesses like asthma or diabetes.
- Bacterial superinfection of manipulated lesions
How to take care of your skin if you have acne?
- Cleanse the face twice daily with a mild, soap-free, non-comedogenic cleanser and lukewarm water
- Use non-comedogenic moisturizers and sunscreen, especially when using retinoids or isotretinoin.
- Avoid touching, scratching, or picking at lesions: this worsens inflammation and leaves scars.
- Choose cosmetics and foundations labeled non-comedogenic or dermatologically tested
- Adopt a low glycemic index diet and limit skim milk consumption if a correlation is observed with flare-ups.
- Managing stress with appropriate techniques: physical activity, sufficient sleep, relaxation
- Do not interrupt a prescribed treatment as soon as the lesions improve: maintenance treatment prevents relapses.
Consult at Clinique Omicron
If your acne resists pharmacy treatments after a few weeks, leaves scars, or affects your daily life or self-esteem, a medical consultation is recommended. Clinique Omicron doctors, at their service points in Quebec, can assess the severity of your acne, identify triggers, prescribe appropriate treatment, and refer you to a dermatologist if necessary.
The content of this page is provided for informational purposes only and is not intended to replace the advice of a qualified healthcare professional. Consult a physician for any symptoms, questions or decisions you may have regarding your health.
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