Educational Content: This article is for informational purposes only and does not constitute medical advice. Always consult a healthcare provider for diagnosis and treatment.
Definition of Erythema chronicum migrans
Medically reviewed by Min Clinic Staff | Updated: January 2026
Erythema chronicum migrans: The classic initial rash of Lyme disease. In the early phase of the illness, within hours to weeks of the tick bite, the local skin develops an expanding ring of unraised redness. There may be an outer ring of brighter redness and a central area of clearing. For more information, see Lyme Disease.