Granulomatous Rosacea — SCE Dermatology MCQ

Correct answer: B — Cutaneous sarcoidosis (non-caseating granulomas)

The correct answer is B, cutaneous sarcoidosis (non-caseating granulomas). Granulomatous rosacea produces yellowish-brown, firm papules on the cheeks and periorificial skin with non-caseating epithelioid granulomas on histology, a pattern that is histologically indistinguishable from cutaneous sarcoidosis. Because both conditions can be confined to the face with near-identical clinical morphology and granulomatous architecture, sarcoidosis must be actively excluded before labelling the eruption as rosacea, since sarcoidosis is a multisystem disease with pulmonary, ocular, and lymph node involvement and carries different management and monitoring implications. Exclusion relies on clinical correlation (absence of hilar lymphadenopathy, normal serum ACE and calcium, no extrafacial infiltrates or lupus pernio) plus special stains to exclude mycobacterial infection, as granuloma morphology alone cannot separate the two. Why the other options are wrong: C. Eczema: presents with pruritic, eczematous, often flexural or facial dermatitis with spongiosis on biopsy, not granulomatous inflammation, so histology readily excludes it without further work-up. E. Acne vulgaris: shows comedones, inflammatory pustules and follicular plugging with a neutrophilic or suppurative infiltrate, not epithelioid granulomas, so it is not histologically confusable with granulomatous rosacea. A. Psoriasis: has characteristic psoriasiform epidermal hyperplasia with parakeratosis and Munro microabscesses, a pattern entirely distinct from dermal granulomas and easily separated on biopsy. D. Tinea faciei: is an infective, scaly, annular eruption in which fungal hyphae are seen on PAS or potassium hydroxide preparation rather than granulomas, and it responds to antifungals rather than anti-rosacea therapy. Key point: yellowish-brown facial papules with non-caseating granulomas are shared by granulomatous rosacea and cutaneous sarcoidosis, so systemic sarcoidosis must be excluded (ACE, calcium, chest imaging, extrafacial disease) before confirming the diagnosis.

Reference: DermNet NZ (authored with East Lancashire NHS Trust dermatology), Sarcoidosis, reviewed 2025, https://dermnetnz.org/topics/sarcoidosis