Erythema chronicum migrans refers to the rash often (though not always) seen in the early stage of Lyme disease.

An example of such a test is the inspection for erythema chronicum migrans to diagnose lyme disease.

Erythema chronicum migrans.

This rash is now known as erythema chronicum migrans, the skin rash found in early-stage Lyme disease.

Diagnosis is based on a circular "bulls eye" rash at the site of infection called Erythema chronicum migrans, which is very similar to that seen in Lyme disease.

In most cases, Lyme disease is first characterized by the appearance of a red skin lesion (erythema chronicum migrans), which begins as a small elevated round spot (papule) that expands to at least five centimeters in diameter.

Lyme disease clinical features include the characteristic bull's eye rash and erythema chronicum migrans (a rash which spreads peripherally and spares the central part), as well as myocarditis, cardiomyopathy, arrythmia, arthritis, arthralgia, meningitis, neuropathies and facial nerve palsy.

The classic sign of early local infection with Lyme disease is a circular, outwardly expanding rash called erythema chronicum migrans (also erythema migrans or EM), which occurs at the site of the tick bite three to thirty days after the tick bite.