Other Tick-Borne Illnesses
While Lyme disease is by far the most commonly reported tick-borne illness, several others can be serious — and some are potentially life-threatening without prompt treatment. It is important for anyone with tick exposure and illness to understand the full spectrum of tick-borne diseases their provider should consider.
Rocky Mountain Spotted Fever (RMSF)
Caused by Rickettsia rickettsii, transmitted primarily by the American dog tick and Rocky Mountain wood tick. RMSF is one of the most severe tick-borne diseases in the US and can be fatal if not treated promptly. The characteristic spotted rash typically begins on wrists and ankles 2–4 days after fever onset. Doxycycline is the treatment — and early initiation is critical.
Ehrlichiosis
Caused by Ehrlichia bacteria, transmitted primarily by the lone star tick. Symptoms (fever, headache, fatigue, muscle aches) typically begin 1–2 weeks after a bite. Often presents with low white blood cell count. Treatable with doxycycline.
Anaplasmosis
Caused by Anaplasma phagocytophilum, transmitted by the same black-legged tick that carries Lyme. A common co-infection. Symptoms mirror early Lyme — fever, headache, muscle aches. Doxycycline treats both simultaneously. See our Co-Infections page.
Babesiosis
A parasitic infection of red blood cells. Can range from mild flu-like illness to life-threatening hemolytic anemia, particularly in older adults or immunocompromised patients. Does NOT respond to doxycycline — requires antiparasitic treatment with atovaquone plus azithromycin.
Powassan Virus Disease
A rare but serious viral illness transmitted by black-legged ticks. Unlike bacterial tick-borne diseases, there is no specific antiviral treatment. Powassan can cause brain inflammation (encephalitis). Case fatality rate is approximately 10–15%. Can be transmitted in as few as 15 minutes of tick attachment.
Tularemia
Caused by Francisella tularensis. Can be acquired through tick bites, contact with infected animals, or inhalation. A range of clinical forms depending on route of entry. Treatable with aminoglycosides or doxycycline.