Pathology of Erythema Migrans - Dr Sampurna Roy MD

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Pathology of Erythema Migrans

Erythema migrans (previously known as erythema chronicum migrans) represents the skin lesion associated with Lyme disease, a tick-borne illness caused by the spirochete Borrelia burgdorferi.

The annular lesion, (measures 5-20 cm in diameter) develops within 3 months of the tick bite.

Lesions are multiple in some cases.

Secondary erythema migrans result from hematogenous spread of the organism.

The organism disappear from the lesion after treatment with antibiotics (doxycycline and synthetic penicillin).

Microscopic features:

Histologically, there is a superficial and deep perivascular and interstitial infiltrate of lymphocytes.

In some cases plasma cells and eosinophils are present. Eosinophils may be present at the site of tick bite. A few neutrophils may also be noted.

Special stain : Warthin-Starry silver stain - In some specimens spirochetes are identified in the papillary dermis at the dermoepidermal junction.

Diagnosis may be confirmed by using an indirect immunofluorescence or immunoperoxidase techniques.

Borellia burgdorferi may also be identified in formalin-fixed paraffin-embedded lesions by polymerase chain reaction method.