erythema migrans
Characteristic expanding red rash of early Lyme disease, typically appearing 3-30 days after tick bite.
Full Definition
The pathognomonic skin lesion of early localized Lyme disease, caused by Borrelia burgdorferi infection following Ixodes tick bite. The rash begins as a small red area that expands over days to weeks, often developing central clearing to create a 'bull's-eye' appearance, though this classic pattern occurs in less than half of cases. Erythema migrans lesions are typically painless and non-pruritic, distinguishing them from other inflammatory skin conditions. In pediatric patients, recognition of erythema migrans is crucial for early diagnosis and treatment of Lyme disease, preventing progression to disseminated infection.
Usage
Usage note: Maintain Latin terminology; 'erythema migrans' is preferred over 'erythema chronicum migrans'.
In Context
- "The diagnosis of early Lyme disease was established based on the characteristic erythema migrans lesion and tick exposure history." — Pediatric infectious disease consultation
- "Erythema migrans may appear atypical in children, lacking the classic central clearing seen in adult presentations." — Dermatology case series