Southern Tick Associated Rash Illness (STARI), also known as Master’s disease, is an emerging tick-borne disease transmitted to people by the bite of a Lone Star tick. The germ (pathogen) that causes STARI has not yet been identified. Individuals with STARI often develop a characteristic bull’s eye rash, similar to the rash found in individuals with Lyme disease.

Lone Star Tick
Lone Star Tick
Photo source, CDC

Ticks That Carry It

Lone Star ticks are the carriers of the germs (pathogen) that cause STARI in humans. Adult female Lone Star ticks are easy to recognize because of the conspicuous white dot which gives this tick its name.

Lone Star ticks are aggressive human biters. While these ticks may be more concentrated in the south, their range extends across most of the eastern half of the U.S. and as far north as Maine. In addition to STARI, these ticks are known to transmit germs (pathogens) that cause Ehrlichiosis, Heartland virus disease, Bourbon virus disease, Alpha-gal, and Tularemia.

Where STARI Is Found

STARI occurs predominantly in the southeastern United States. Cases have been reported from central Texas and Oklahoma upward and eastward, including the southern states and along the Atlantic coast into Maine.

The map below shows where the Lone Star tick has been found and how it has expanded its territory. This is the tick that transmits STARI to humans. STARI is typically reported in the purple states.

Lone star tick expansion since 1986
Map source: Don Walter Kannangara and Pritiben Patel. Report of Non-Lyme, Erythema Migrans Rashes from New Jersey with a Review of Possible Role of Tick Salivary Toxins. Vector-Borne and Zoonotic Diseases. Dec 2018.641-652.


STARI symptoms include a bull’s eye-shaped rash that forms around the site of the Lone Star tick bite within 7 days. Although the bull’s eye rash is similar to that seen in individuals with Lyme disease, STARI and Lyme disease are different illnesses and the bull’s eye rashes are different, too.

  • The bull’s eye rash seen with Lyme disease can appear anywhere on the body in addition to the spot where the tick bite occurred. In STARI, the rash is only at the site of the bite.
  • Individuals with Lyme disease sometimes have multiple bull’s eye rashes, but those with STARI have just one.
  • In one study, STARI rashes cleared up after 12 days while Lyme rashes lasted for up to 39 days.
  • STARI bull’s eye rashes may be smaller in size than those seen with Lyme disease (2-4 inches for STARI vs. 2-11 inches for Lyme disease).
  • STARI bull’s eye rashes are more circular in shape with a clear center.

Other STARI Symptoms May Include

  • Fatigue
  • Fever
  • Headache
  • Muscle and joint pain

Other Differences Between STARI and Lyme Disease

  • Individuals with a STARI bull’s eye rash were less likely to have other symptoms frequently seen with Lyme disease.
  • Individuals infected with STARI tend to have fewer symptoms and may recover more quickly than individuals with Lyme disease.
  • After antibiotic treatment, individuals with STARI have recovered more rapidly than those with Lyme disease.

Who Is Most at Risk?

Those who work outside and/or enjoy outdoor recreational activities in areas where Lone Star ticks are found are typically at higher risk.


It is not known whether antibiotic treatment is necessary or beneficial for individuals with STARI. Nevertheless, because STARI resembles early Lyme disease, physicians often treat individuals with oral antibiotics.


Although Lone Star ticks are most active in May and June it is possible to find the adults active on warm days throughout the winter and early spring. To help prevent bites, when going outside, use repellents containing DEET (or other EPA-registered active ingredients) according to label directions. The American Academy of Pediatrics and the Centers for Disease Control and Prevention note that products containing up to 30% DEET are appropriate for children over two months of age. For more information, please visit our prevention page.