Southern Tick-Associated Rash Illness

Southern tick-associated rash illness (STARI), also known as Masters disease, is a newly recognized tickborne disease that produces a rash similar to that caused by Lyme disease. STARI is associated with the bite of the lone star tick, Amblyomma americanum, which is found in the south-central and southeast United States, including Texas and Oklahoma, and along the Atlantic coastline, all the way to Maine.

Causes

Deoxyribonucleic acid analysis of the spirochetes found in the A. americanum tick has indicated that these ticks differ from Borrelia burgdorferi—the agent of Lyme disease. A. americanum ticks have three life stages, all of which have been found to aggressively bite people. (See The lone star tick.)

Complications

There are no known complications of STARI.

Assessment Findings

Patients may present with some symptoms similar to those of Lyme disease, such as an expanding red rash with central clearing, similar to a “bull’s-eye,” that usually appears within 7 days of the tick bite. It may have a diameter of 3″ (8 cm) or larger. Mild illness, characterized by such signs and symptoms as fatigue, headache, joint and muscle pain, stiff neck and, occasionally, fever, may accompany the rash.

Diagnostic Tests

Although there are no current specific diagnostic tests for STARI, the illness is strongly suspected if diagnostic tests rule out Lyme disease, if the patient lives in or has travelled to an area where the tick is commonly found, or if a known lone star tick bite has been reported or the patient has participated in activities that may have resulted in exposure to ticks.