The pathognomonic erythematous rash in the pattern of a bullseye, which manifested at the site of a tick bite on a woman's posterior right upper arm. She subsequently contracted Lyme disease. Lyme disease patients who are diagnosed early, and receive proper antibiotic treatment, usually recover rapidly and completely. A key component of early diagnosis is recognition of the characteristic Lyme disease rash called erythema migrans. This rash often manifests itself in a bullseye appearance, and is observed in about 80% of Lyme disease patients. Lyme disease is caused by the bacterium Borrelia burgdorferi, and is transmitted to humans by the bite of infected blacklegged ticks. Typical symptoms include fever, headache, fatigue, and as illustrated here, the characteristic bullseye skin rash. If left untreated, infection can spread to joints, the heart, and the nervous system.
