Tick-borne disease
Ehrlichiosis
Ehrlichia chaffeensis
A flu-like bacterial infection that hides inside your white blood cells — easy to miss, and important to catch.
The pathogen
What it is.
Ehrlichiosis is caused by Ehrlichia bacteria, most often spread by the lone star tick. The bacteria multiply inside white blood cells, forming tiny mulberry-like clusters called morulae. Illness tends to begin within one to two weeks of a bite.
Carried by
Lone star tick · Amblyomma americanum
Signs & symptoms
What to watch for.
Symptoms usually begin 1 to 2 weeks after a bite:
- Fever, chills, and severe headache
- Muscle aches and deep fatigue
- Nausea, vomiting, or loss of appetite
- Sometimes a rash (more common in children)
Bloodwork often shows low white cells or platelets and elevated liver enzymes. It responds quickly to the right antibiotic, but can become serious if it is missed.
How it spreads
Transmission
Ehrlichiosis spreads through the bite of an infected lone star tick, and less often the blacklegged tick. Symptoms usually begin one to two weeks after the bite. Unlike Lyme, there is no single-dose prevention — it is diagnosed and treated once symptoms appear.
How it’s treated
Treatment
Ehrlichiosis is treated with doxycycline and responds quickly when caught early. Because it can lower your blood counts and affect the liver, diagnosis usually involves bloodwork — so a symptomatic case is evaluated by a physician, in person when needed, rather than treated blindly. We will help you find that care.
When to seek care
Don’t wait on these.
Seek care promptly for a high fever, confusion, difficulty breathing, or a severe headache after a tick bite. Ehrlichiosis can become serious, especially in older adults or anyone with a weakened immune system.
Prevention
Lowering your risk.
The surest protection is avoiding bites in the first place: use an EPA-registered repellent, treat clothing and gear with permethrin, stay toward the center of trails, and do a full-body tick check after time outdoors — including the scalp, behind the knees, and the waistline. If you find an attached tick, remove it promptly with fine-tipped tweezers, pulling straight up without twisting, and note the date. The sooner it comes off, the lower the risk.
The physician
Dr. Adam Kawalek
Board-certified in Internal Medicine — American Board of Internal Medicine. Trained at Brown, Mount Sinai and Johns Hopkins. He reads every case personally.
Bitten recently? The clock matters more than the worry.
A licensed physician reviews every case