skip to main content

Erythema Migrans Treatment — SCE Infectious Diseases MCQ

Instant feedback + full explanation. One question, done properly.

EasyCNS InfectionErythema Migrans TreatmentSCE Infectious Diseases

A 40-year-old man develops erythema migrans (a 15 cm expanding annular erythematous lesion with central clearing) on his thigh. He reports a tick bite 10 days ago while hiking in Hampshire. What is the first-line treatment?

Educational content. Not a substitute for clinical judgement or local policy.

Reveal the answer and explanation

Correct answer: B — Oral Doxycycline 100 mg BD for 21 days (or oral Amoxicillin 1 g TDS for 21 days if Doxycycline is contraindicated)

Erythema migrans (EM) is the clinical hallmark of early Lyme disease (Borrelia burgdorferi). NICE NG95 recommends treating EM clinically without waiting for serology (which may be negative in early disease). First-line treatment is oral Doxycycline 100 mg BD for 21 days. Amoxicillin (1 g TDS for 21 days) is an alternative for children, pregnant women, and those intolerant of Doxycycline. IV Ceftriaxone is reserved for Lyme with CNS involvement (neuroborreliosis with CSF pleocytosis). Hampshire is a Lyme-endemic area in the UK.

Reference: NICE NG95 2018 – Lyme disease; UKHSA 2024 – Lyme disease