Tick-Borne Diseases and Their Symptoms

Last updated: June 2026

Here's the full rundown of what ticks in this country can actually give you, what it looks like, and how fast you need to move on each one.

Most common

Lyme Disease

Caused by Borrelia burgdorferi, transmitted by black-legged ticks. The bullseye rash everybody talks about, doctors call it erythema migrans, shows up in about 70 to 80 percent of people who get it. It spreads out from the bite, sometimes with a lighter patch in the middle, sometimes not in any particular pattern at all. About 1 in 5 confirmed cases never even gets a rash.

Early on you'll see things like fatigue that feels off, fever, chills, headache, aching joints and muscles. Can start a few days after the bite or take a few weeks to show up. Catch it early with antibiotics and most people are fine. Let it go and Lyme can turn into joint problems, heart rhythm issues, and nerve trouble including facial paralysis and shooting pains. The CDC's own page on this, cdc.gov/lyme, is the source I'd check first if anything here seems off or out of date.

Serious: same-day care if you suspect this

Rocky Mountain Spotted Fever

Despite the name, this shows up all over the country, not just out west. It's one of the nastier tick diseases we've got, and it can kill you if antibiotics don't start soon enough. Symptoms come on 2 to 14 days after the bite: high fever, a bad headache, and often a spotted rash that starts on the wrists and ankles. That rash doesn't always show up early, so don't wait on it. If you've had a tick bite and a sudden high fever with a bad headache shows up, get to a doctor that same day. Doxycycline works great if you start it soon enough. The timing here genuinely matters more than with most of these. CDC's page is at cdc.gov/rocky-mountain-spotted-fever.

Common, responds well to treatment

Anaplasmosis and Ehrlichiosis

Two different bacterial infections that look almost identical: fever, a bad headache, sore muscles, chills, all within one to two weeks of the bite. Anaplasmosis comes from deer ticks, ehrlichiosis mostly from lone star ticks. Both clear up well with doxycycline once you're on it. Left alone, either one can turn into respiratory failure or organ damage. CDC has a dedicated page for each: cdc.gov/anaplasmosis and cdc.gov/ehrlichiosis.

Emerging concern

Alpha-Gal Syndrome

A lone star tick bite can set off an allergic reaction to alpha-gal, a sugar found in red meat and some dairy. It's a delayed reaction, showing up 2 to 6 hours after eating beef, pork, or lamb, per CDC's own timing. Can range from hives and stomach cramps all the way to a full anaphylactic reaction. A lot of people never connect it to a tick bite because months or even years can go by before the first reaction. There's no cure. If you start having a strange delayed reaction to red meat and you've spent time where lone star ticks live, an allergist can run a blood test for it, specifically an alpha-gal IgE antibody test.

This one's personal for us. My wife has it, and it took a long while before anyone figured out why. If you've got hives or stomach trouble or some kind of reaction a few hours after a cookout and nobody can explain it, bring up alpha-gal yourself. A lot of doctors won't think to test for it on their own. CDC's dedicated alpha-gal site at cdc.gov/alpha-gal-syndrome is worth reading directly, and they even publish a free printable brochure aimed at hunters specifically, since hunting puts you in exactly the kind of lone star tick habitat that causes this. See the alpha-gal page here for how big this thing has actually gotten.

Rare but requires urgent awareness

Powassan Virus

Most tick diseases need the tick attached for hours before they can pass anything to you. Powassan can do it in as little as 15 minutes. Most folks who get it have mild symptoms or none at all. When it does cause brain swelling, you're looking at fever, headache, vomiting, confusion, weakness, and in bad cases, seizures. About half the people who get hit hard neurologically end up with lasting effects, and roughly 1 in 5 severe cases is fatal. No specific antiviral for it. Still rare, but it's showing up more in the Northeast and around the Great Lakes. CDC's page: cdc.gov/powassan.

Blood parasite

Babesiosis

A parasite that gets into your red blood cells, kind of like malaria, carried by deer ticks. A lot of people barely notice it or have nothing at all. In older folks, anyone immunocompromised, or someone without a spleen, it can turn into high fever, heavy sweating, jaundice, even organ failure. Needs its own antiparasitic medicine, regular Lyme antibiotics won't touch it. Mostly seen along the coast of New England, New York, New Jersey, and up in the upper Midwest. CDC's page: cdc.gov/babesiosis.

How to Check This Yourself

I'm not a doctor, so don't take any of the above as the final word on what's happening with your body. I've linked the actual CDC page for each disease right where it's discussed above, so you can read the primary source directly rather than just taking my word for it. A few other places worth knowing about:

• For the full CDC tick disease overview: cdc.gov/ticks/about is the page that links out to every disease CDC tracks, including a few rare ones not covered here.
• For a second opinion on symptoms and treatment: the Infectious Diseases Society of America (IDSA) publishes the clinical practice guidelines doctors actually use for treating Lyme and other tick-borne illness. Their guidelines are public at idsociety.org if you want to read the same thing your doctor would be working from.
• If you think you're dealing with one of these right now: don't wait on a website, including this one, to confirm it. Call your doctor or an urgent care and tell them about the tick bite specifically, even if it was weeks ago. The timing and the bite history are exactly the details that help a doctor move fast.
• If something here doesn't match what your doctor is telling you: trust your doctor. They can see your actual labs, your actual symptoms, and your actual history. This page is general information for people trying to understand what they might be dealing with, not a diagnosis for any one person.

See the data sources page for the full list of government and research sources I draw on across the whole site, not just this page.

See the data sources page for the full list of government and research sources I draw on across the whole site, not just this page.