Epidemiology And Pathogenesis

Occurs universally in nearly all peripubertal children.
Onset peaks between 12-14 years; begins earlier in females.
Subsides by third decade in approximately 70 percent of individuals.
Affects both sexes equally overall; nodulocystic variant manifests more frequently in males.
Pathogenesis multifactorial; involves direct pilosebaceous unit inflammation.
Increased sebum secretion driven by enhanced sebaceous gland sensitivity to circulating androgens.
Microbial colonization primarily involves Propionibacterium acne.
Follicular occlusion occurs via keratin plugs forming comedones, retaining sebum, promoting microbial growth.
Distended follicle rupture releases inflammatory mediators into dermis, stimulating intense inflammation.

Clinical Manifestations And Morphology

Microcomedone progresses gradually to visible comedone.
Open comedone (blackhead) features patulous pilosebaceous orifice permitting plug visualization.
Closed comedone (whitehead) exhibits pinpoint opening.
Inflammatory papules and pustules develop from superficial dermal inflammation secondary to comedone rupture.
Nodules form from deeper dermal inflammatory infiltrates.
Nodulocystic lesions represent liquefied masses of inflammatory debris, not true cysts.

Severity Grade	Clinical Description
Mild	Comedones predominant; fewer than 10 small papules or pustules present.
Moderate	10-40 papules and pustules; 10-40 comedones; mild trunk involvement often present.
Moderately Severe	40-100 papules and pustules; 40-100 comedones; up to 5 large nodular lesions; widespread facial and truncal distribution.
Severe	Nodulocystic or conglobate acne; numerous large, painful inflammatory lesions interspersed with smaller papules and comedones.

Dietary influences include high nonfat milk ingestion and high-glycemic-load diets.
Climate impacts disease severity; winter flares common.
Emotional tension and fatigue exacerbate flares.
Premenstrual exacerbations occur in 25-50 percent of affected females.
Drug-induced variants triggered by corticosteroids, androgens, isoniazid, anticonvulsants, and lithium.

Pharmacologic Class	Specific Agents And Utility
Topical Retinoids	Tretinoin, Adapalene, Tazarotene. First-line therapy. Normalizes desquamation; inhibits microcomedone formation.
Antimicrobials	Benzoyl peroxide. Antimicrobial and mild comedolytic; prevents bacterial resistance.
Topical Antibiotics	Clindamycin. Targets inflammatory acne. Never prescribe as monotherapy; consistently combine with Benzoyl peroxide to prevent resistance.
Keratolytics	Azelaic acid. Resolves postinflammatory dyspigmentation; offers mild antimicrobial properties.

Pharmacologic Class	Specific Agents	Clinical Indications And Monitoring
Oral Antibiotics	Tetracycline, Doxycycline, Minocycline.	Indicated for moderate-severe papulopustular and nodulocystic disease. Limit duration to 3-6 months. Always combine with topical retinoid or benzoyl peroxide.
Hormonal Therapy	Oral contraceptives, Spironolactone.	Indicated for females unresponsive to antibiotic therapy or exhibiting hyperandrogenism.
Systemic Retinoids	Isotretinoin.	Reserved for severe nodulocystic or refractory acne. Highly teratogenic; mandates strict pregnancy prevention program. Requires lipid and hepatic monitoring. Side effects include cheilitis, xerosis, epistaxis, and potential mood changes.

Intralesional triamcinolone injection expedites painful nodulocystic lesion healing.
Dermabrasion or laser resurfacing indicated strictly post-active disease for residual scarring management.