Pseudofolliculitis Barbae — SCE Dermatology MCQ

Correct answer: C — Pseudofolliculitis barbae

The correct answer is C, pseudofolliculitis barbae. This diagnosis fits a young man who shaves daily and develops follicular papules and pustules with occasional ingrown hairs in the beard area, the classic pattern of shaved curled hairs re-entering the skin and provoking a foreign-body type inflammatory reaction rather than an infective process. A negative KOH excludes a dermatophyte cause, and the description specifically mentions ingrown hairs, which is the hallmark clinical clue pointing away from infective or acneiform folliculitis. Pseudofolliculitis barbae is most common in men with curly or coarse facial hair who shave closely, and lesions typically resolve or improve when shaving is stopped, supporting the mechanical rather than infective aetiology. Why the other options are wrong: E. Acne vulgaris: presents with comedones, papules, pustules and nodules related to pilosebaceous unit disease and sebum, not specifically triggered by shaving, and ingrown hairs are not a feature. A. Staphylococcal folliculitis: would typically show tender pustules centred on follicles with a positive bacterial culture or Gram stain, and is not characteristically linked to ingrown hairs from shaving. D. Tinea barbae: is a dermatophyte infection of the beard, usually acquired from animal contact, and would be expected to give a positive KOH microscopy, which is negative here. B. Rosacea: causes facial erythema, telangiectasia, papules and pustules typically over the central face (nose, cheeks, chin) with flushing triggers, not confined to shaved areas and not associated with ingrown hairs. Key point: Follicular papules and pustules with ingrown hairs after shaving in a beard-bearing man, with a negative KOH, is diagnostic of pseudofolliculitis barbae rather than an infective or acneiform folliculitis.

Reference: DermNet NZ, Pseudofolliculitis Barbae (Razor Bumps): Images and Management, https://dermnetnz.org/topics/pseudofolliculitis-barbae