The many masks of cutaneous Lyme disease

Area of Science:

• Dermatology
• Infectious Diseases
• Pathology

Background:

• Early cutaneous Lyme disease, erythema migrans, is caused by Borrelia burgdorferi infection following a tick bite.
• The classic presentation is a solitary, annular, 'bull's-eye' lesion.
• Histopathologic findings can vary, potentially leading to misdiagnosis.

Purpose of the Study:

• To highlight the diverse histopathologic patterns observed in early cutaneous Lyme disease.
• To increase awareness among clinicians to prevent misdiagnosis.
• To emphasize the importance of considering erythema migrans in the differential diagnosis.

Main Methods:

• A case series reviewing eight patients with early erythema migrans.
• Confirmation of Borrelia burgdorferi infection through serological testing (IgM positive, IgG negative).
• Detailed histopathologic evaluation of skin biopsies.

Main Results:

• Seven out of eight cases exhibited sparse to mild inflammatory infiltrates, deviating from the typical dense infiltrate.
• Histopathology revealed varied patterns including perivascular, interstitial, epidermal changes (spongiosis, interface change), perineural, and periadnexal infiltrates.
• One case showed a dense inflammatory infiltrate.

Conclusions:

• The histopathologic presentation of erythema migrans is more variable than classically described.
• Awareness of these diverse patterns is essential for accurate diagnosis and treatment of Lyme disease.
• Considering erythema migrans in the differential diagnosis aids prompt management.