Southern tick-associated rash illness reports becoming more widespread

July 1, 2008

Southern tick-associated rash illness (STARI) presents similar to Lyme disease with an enlarging, erythematous, annular patch or plaque, but may differ from Lyme disease in several respects. Clinical features of STARI and considerations for the diagnosis and treatment of Lyme disease are discussed.

Key Points

"STARI is a relatively recently described tick-borne disease that is rapidly appearing across the country. Similar to Lyme disease, the initial reported cases of STARI were confined to specific geographic regions, but more widespread reports of affected patients are emerging," says Dr. Lebwohl, Sol and Clara Kest Professor and Chairman, department of dermatology, Mount Sinai School of Medicine, New York.

"Although STARI was named because the first cases occurred among patients residing in southern U.S. states, STARI may be a more accurate descriptor, because clinical cases and/or identification of the putative pathogen in the tick vector have now been reported in Missouri and states in the Northeast," Dr. Lebwohl tells Dermatology Times.

Similar to Lyme disease, the STARI skin manifestation is characterized by an enlarging annular patch or plaque around the site of a tick bite - in the case of STARI, the vector is the lone star tick (Amblyomma americanum).

However, STARI is also caused by a different bacterial organism and seems to differ from Lyme disease in a number of other clinical features.

"STARI is a different illness from Lyme disease. STARI is thought to be caused by the spirochete Borrelia lonestari, and serologic tests for antibodies to Borrelia burgdorferi, the bacterial pathogen causing Lyme disease, do not cross-react to STARI," Dr. Lebwohl says.

The STARI rash also differs in several respects from the skin eruption associated with Lyme disease. The onset of appearance is faster in patients with STARI, and they are more likely to have just a single primary lesion versus multiple lesions.

The STARI lesion also tends to be smaller and more circular than erythema migrans associated with Lyme disease, and more likely to show central clearing.

"The STARI rash usually appears within one week of the tick bite, and patients with STARI are more likely than their counterparts with Lyme disease to recall having been bitten by a tick," Dr. Lebwohl says.

Patients with STARI are also generally less symptomatic than patients with Lyme disease, and thus far, STARI is not associated with cardiac, joint and neurologic sequelae, as is Lyme disease.

"Serology is only positive about 50 percent of the time; histology is nonspecific - although spirochetes on silver stains strongly support the diagnosis - culture is difficult and also only positive 50 percent of the time; and, depending on the laboratory, PCR is positive anywhere from 36 to 88 percent of the time," Dr. Lebwohl says.