The Many Presentations of the Lyme Disease Rash

The Lyme disease rash, known as erythema migrans (EM), can appear in many different forms. While many people associate Lyme disease with the classic bull’s-eye rash, research shows that most Lyme disease rashes look very different from this textbook pattern.

In the study “The Spectrum of Erythema Migrans in Early Lyme Disease: Can We Improve Its Recognition?”, investigators examined photographs of skin lesions from 69 individuals suspected of having early Lyme disease. The participants included 43 men and 26 women. Most participants (83%) presented with a single lesion.¹

The images were retrospectively evaluated by a dermatologist and a family physician with expertise in early Lyme disease.

Different Types of Lyme Disease Rashes

The investigators found that:

• 35 lesions (51%) were confirmed erythema migrans (EM)
• 23 lesions (30%) were considered possible early EM or tick bite reactions
• 11 lesions (16%) were thought to be other skin conditions such as ringworm, allergic contact dermatitis, or mosquito bites

“Only two lesions (6%) showed the classic bull’s-eye or ring-within-a-ring appearance.”

This finding highlights how uncommon the classic bull’s-eye Lyme disease rash actually is.

EM rashes were most commonly located on the abdomen, thigh, back, and hip.

Symptoms Associated With the Lyme Disease Rash

Participants with an erythema migrans rash frequently reported symptoms including:

• Chills
• Fever
• Night sweats
• Headache
• Fatigue
• Body aches
• Nausea
• Neuralgia

Common Characteristics of EM Rashes

Most erythema migrans lesions appeared:

• Uniform in appearance (51%)
• Pink in color (74%)
• Oval in shape (63%)
• With well-defined borders (92%)

These findings reinforce that the Lyme disease rash often appears as a simple expanding red patch rather than a bull’s-eye.

Early EM vs Tick Bite Reactions

Early erythema migrans lesions or tick bite reactions typically appeared:

• Smaller than 5 cm (74%)
• Red in color (52%)
• Round in shape (61%)
• With a punctum at the center (100%)

Rashes That Were Not Lyme Disease

Lesions determined not to be erythema migrans were commonly:

• Pink or red (64%)
• Round (55%)
• Uniform in appearance (45%)

However, they sometimes had raised borders (25%) or irregular edges (33%), which helped clinicians distinguish them from Lyme disease rashes.

“EM commonly occurs in forms that are not the classic bull’s-eye.”

Interestingly, only 14 participants (20%) had positive laboratory evidence for Lyme disease. Among those with EM-classified lesions, only 13 (37%) had positive test results.

This finding highlights a key clinical issue: many patients with early Lyme disease may test negative using currently available laboratory tests.

VIEW PHOTOS OF ERYTHEMA MIGRANS RASHES

Improving Recognition of the Lyme Disease Rash

The authors emphasize that education should move away from focusing primarily on the bull’s-eye rash. Instead, clinicians and patients should recognize that the Lyme disease rash can vary widely in appearance.

They concluded:

• Patients often present with lesions representing very early erythema migrans or tick bite reactions.
• Many patients with early Lyme disease will test negative using current laboratory tests.
• Improved awareness of the many presentations of the Lyme disease rash may help clinicians diagnose Lyme disease earlier.