From the Guidelines
Lyme Disease and Rash Association
Yes, Lyme disease is often associated with a rash, known as erythema migrans, which is a characteristic expanding skin lesion that usually appears within 3 to 30 days after a tick bite 1.
- The rash can grow up to 12 inches in diameter and may resemble a bull's-eye, with a red outer ring surrounding a clear center.
- It's essential to seek medical attention if you experience a rash or other symptoms like fever, headache, or fatigue after a tick bite, as early treatment with antibiotics such as doxycycline (100 mg twice daily for 10-21 days) or amoxicillin (500 mg three times daily for 14-21 days) can help prevent long-term complications 1.
- Erythema migrans is the only manifestation of Lyme disease that is sufficiently distinctive to allow clinical diagnosis in the absence of laboratory confirmation, especially in patients with a compatible epidemiologic and clinical history 1.
- Approximately 70%–80% of persons with Lyme disease have erythema migrans, making it a key diagnostic criterion 1.
From the Research
Association between Rash and Lyme Disease
- A rash, specifically erythema migrans, is a common manifestation of Lyme disease, typically developing days to weeks after a tick bite 2, 3, 4, 5.
- The rash is often characterized by an expanding erythematous skin lesion, which may have a bull's-eye appearance, although central clearing may be absent in over 50% of patients 2, 5.
- Erythema migrans is usually accompanied by other symptoms such as fatigue, myalgia, arthralgia, headache, and fever, although these complaints are generally mild 2.
Differential Diagnosis
- Not all erythema migrans-like rashes are due to Lyme disease, as similar lesions can occur after bites from other ticks, such as the lone star tick, and may be caused by other conditions like southern tick-associated rash illness 6, 3.
- Diagnosis of erythema migrans is based on clinical findings, including the appearance of the skin lesion and a history of a recent tick bite, rather than on laboratory testing 3, 4, 5.
Treatment and Prognosis
- Antibiotic treatment, such as amoxicillin or doxycycline, is effective in preventing the progression of Lyme disease to its later stages and can clear signs and symptoms in about 90% of patients 4, 5.
- The prognosis is excellent after treatment with an appropriate oral antibiotic for 10 to 14 days, although some patients may experience persistent effusion despite antibiotic therapy 3, 5.