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Rickettsia — SCE Infectious Diseases MCQ

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ModerateTropical & Imported InfectionsRickettsiaSCE Infectious Diseases

A 52-year-old farmer presents with an eschar on his ankle surrounded by erythema, regional lymphadenopathy, and fever after working in scrubland in southern France. What is the most likely diagnosis and treatment?

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Correct answer: C — Mediterranean spotted fever (Rickettsia conorii); Doxycycline 100 mg BD for 7 days

A necrotic eschar (tache noire) with fever and lymphadenopathy after outdoor exposure in the Mediterranean region is classic for Mediterranean spotted fever caused by Rickettsia conorii, transmitted by the brown dog tick. Doxycycline 100 mg BD is the treatment of choice for all rickettsial infections. Lyme disease (Borrelia burgdorferi) presents with erythema migrans without eschar. Cutaneous anthrax has a painless black eschar but without the tick exposure context.

Reference: UKHSA 2023 – Rickettsial infections; WHO 2020 – Tick-borne rickettsioses