Buruli ulcer — DTM&H MCQ

Correct answer: D — Buruli ulcer

The correct answer is D, Buruli ulcer, caused by Mycobacterium ulcerans, a slow-growing environmental mycobacterium acquired through skin contact or minor trauma near stagnant or slow-flowing water in tropical Africa. The disease characteristically begins as a painless subcutaneous nodule that, without treatment, progresses over weeks to a necrotic ulcer with classically undermined edges and minimal systemic upset, exactly as described in this Ghanaian child. Children in wetland-associated rural West African communities are the highest-risk group, and this epidemiological and clinical pattern is the recognised WHO case definition for Buruli ulcer. Early recognition matters because prompt rifampicin-based combination antibiotic therapy can prevent the extensive tissue destruction and disability associated with late presentation. Why the other options are wrong: B. Pyoderma gangrenosum: this is a painful, rapidly progressive neutrophilic dermatosis typically associated with inflammatory bowel disease or other systemic autoimmune conditions, not a painless wetland-associated nodule in a child. E. Cutaneous leishmaniasis: ulcers occur after sandfly bites, usually with a raised, indurated, volcano-like border rather than the undermined edge typical of Buruli ulcer, and there is no wetland association. C. Yaws: caused by Treponema pallidum pertenue, this presents with an initial papilloma (mother yaw) that is exudative and crusted, not a firm nodule evolving into an undermined ulcer, and transmission is by direct skin contact, not wetland exposure. A. Tropical ulcer from fusobacteria: these are acutely painful, rapidly developing ulcers with a foul-smelling exudate, usually on the lower leg after minor trauma, contrasting sharply with the painless, indolent Buruli presentation. Key point: a painless leg ulcer with undermined edges in a wetland-exposed African child is the classic hallmark of Buruli ulcer (Mycobacterium ulcerans), distinguishing it from the painful ulcers of tropical ulcer disease and pyoderma gangrenosum.

Reference: World Health Organization, Buruli ulcer (Mycobacterium ulcerans infection) fact sheet, defining the disease as a painless nodule, papule, plaque or oedema evolving into a painless ulcer with undermined edges, https://www.who.int/news-room/fact-sheets/detail/buruli-ulcer-(mycobacterium-ulcerans-infection)