Folliculitis (Skin)

Folliculitis is inflammation centered on hair follicles, producing erythematous, often itchy or tender, papules and pustules at follicular openings. It is the most common pyoderma seen in dermatologic practice and can affect any hair-bearing area, with the beard, scalp, axillae, buttocks, and thighs frequently involved; chronic or recurrent disease can lead to scarring, hyperpigmentation, and follicular destruction.

Causes are categorized as infectious (bacterial: Staphylococcus aureus most common, Gram-negatives in oily skin, Pseudomonas in hot tubs; fungal: Pityrosporum/Malassezia, dermatophytes; viral: herpes simplex, molluscum; parasitic: Demodex), and non-infectious (irritative: shaving, occlusive clothing, oily products; eosinophilic in HIV; pseudofolliculitis barbae; folliculitis decalvans). Diagnosis is clinical with culture, KOH, biopsy, or PCR for refractory cases.

Management starts with identifying the cause, eliminating triggers, and instituting good hygiene (warm compresses, antibacterial cleansers). Topical therapy includes mupirocin, clindamycin, benzoyl peroxide, ketoconazole, or terbinafine; systemic agents are used for extensive bacterial folliculitis (cephalosporin, doxycycline), Pityrosporum (oral itraconazole or fluconazole), or refractory disease. Long-term prevention emphasizes shaving technique, decolonization protocols for recurrent S. aureus, and avoidance of contaminated hot tubs.