Infectious folliculitis
Infectious folliculitis is a superficial inflammation or infection of the hair follicle, most often bacterial (Staphylococcus aureus or hot-tub-associated Pseudomonas aeruginosa) but also fungal, viral, or Demodex, diagnosed clinically and usually self-limited, with topical or oral antistaphylococcal therapy reserved for extensive or refractory disease.
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What this article covers
- Overview
Superficial inflammation or infection centered on the hair follicle: folliculitis presents as pruritic, perifollicular erythematous papules and pustules and can occur on any hair-bearing skin, most often the face, scalp, trunk, and thighs.
- Epidemiology
A common, everyday skin complaint across all ages and skin types, arising anywhere on hair-bearing skin (excluding the palms and soles).
- Risk factors
Occlusive dressings or tight clothing: friction and occlusion favor follicular inflammation and bacterial overgrowth.
- Pathophysiology
Follicular injury creates the portal for infection: shaving, occlusion, friction, or topical irritants disrupt the follicular epithelium, allowing organisms to invade the follicle.
- Clinical features
Pruritic, perifollicular erythematous papules and pustules are the hallmark, most often on the face, scalp, trunk, and thighs, though any hair-bearing skin can be involved.
- Differential diagnosis
Furunculosis (boils): a deeper, perifollicular abscess extending into the dermis and subcutis, presenting as a painful, fluctuant nodule rather than a superficial pustule, usually caused by S.
- Diagnosis
First, folliculitis is diagnosed clinically from the history and characteristic perifollicular papulopustular appearance: no laboratory test is required in typical, mild cases.
- Management
First, determine whether treatment is even needed: when only a few lesions are present, treatment is usually unnecessary because folliculitis is typically self-limited, regardless of organism.
- Complications
Progression to furuncle or carbuncle: untreated or extensive staphylococcal folliculitis can deepen into a follicle-associated abscess (furuncle) or coalesce into a carbuncle with systemic signs.
- Prognosis
Excellent in the great majority of cases: most infectious folliculitis, regardless of organism, resolves spontaneously or with brief topical therapy.
- Prevention
Maintain proper hot tub, pool, and spa water pH and chlorine/disinfectant levels: appropriate disinfection reduces the risk of Pseudomonas folliculitis outbreaks.
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