Acne

Acne is a chronic inflammatory disease of the pilosebaceous unit (hair follicle and sebaceous glands). Particularly prevalent during adolescence common, acne is characterized by comedones (blackheads and whiteheads), papules, pustules, nodules, and cysts like on the face, back, chest, and shoulders. Acne can cause psychosocial stress by affecting physical appearance. The pathogenesis of acne involves follicular hyperkeratinization, increased sebum production, colonization by Cutibacterium acnes (formerly Propionibacterium acnes), and inflammatory processes.

Epidemiology and Risk Factors

Acne most commonly occurs during adolescence and affects approximately 85% of individuals in this age group. However, it can also occur in adults, particularly women (adult-onset acne). Acne is associated with genetic predisposition genetic, hormonal changes (increased androgens), stress, diet (high glycemic index foods, dairy products), and cosmetic products. Additionally, endocrine disorders such as polycystic ovary syndrome (PCOS) can trigger acne.

Pathophysiology

Acne development is based on four key pathophysiological processes:

1. Follicular Hyperkeratinization: Blockage of the hair follicle opening by keratin and sebum leads to comedone formation.
2. Increased Sebum Production: Androgens stimulate increased sebum production.
3. Bacterial Colonization: Cutibacterium acnes proliferates within blocked follicles and triggers an inflammatory response.
4. Inflammation: The immune response induced by C. acnes results in the formation of papules, pustules, and nodules.

These processes determine the clinical spectrum of acne lesions.

Clinical Features

Acne lesions are classified as inflammatory and non-inflammatory:

Non-Inflammatory Lesions

• Comedones:
• • Open comedones (blackheads): The follicular opening is dilated and appears black due to melanin oxidation.
  • Closed comedones (whiteheads): The follicular opening is narrow and matches the skin color.

Inflammatory Lesions

• Papules: Small, red, raised lesions.
• Pustules: Lesions filled with pus, with yellow-white heads.
• Nodules: Deep, firm, painful lesions.
• Cysts: Large lesions filled with pus or sebum.

Acne can be classified as mild, moderate, or severe. Severe acne may lead to scarring.

Diagnosis

The diagnosis of acne is made clinically based on the type, distribution, and severity of lesions. Differential diagnoses include rosacea, folliculitis, perioral dermatitis, and drug-induced acne. If hormonal acne is suspected, serum androgen levels and other endocrine tests may be ordered.

Treatment

Acne treatment is planned according to disease severity and lesion type. Treatment goals include improving existing lesions, preventing new lesion formation, and preventing scarring.

Topical Treatments

• Retinoids: Reduce follicular hyperkeratinization (tretinoin, adapalene).
• Antibiotics: Reduce C. acnes colonization (clindamycin, erythromycin).
• Benzoyl Peroxide: Exhibits antibacterial and keratolytic effects.
• Azelaic Acid: Has anti-inflammatory and antibacterial properties.

Systemic Treatments

• Oral Antibiotics: Used for moderate to severe inflammatory acne (doxycycline, minocycline).
• Hormonal Therapies: Oral contraceptives or spironolactone are used in women to reduce androgen effects.
• Isotretinoin: A vitamin A derivative used for severe acne. It induces long-term remission.

Other Treatments

• Chemical Peels: Used to clear comedones in mild acne.
• Laser and Light Therapies: Effective in reducing inflammatory lesions.
• Scar Treatment: Laser therapy, dermabrasion, or filler agents may be used.