A photograph of a tick crawling on a person's finger.

You might not notice when a tick bites you. So act fast if you experience a fever or rash and have had recent potential exposure to ticks, including being in tall grass, woods, or generally out in nature where ticks live. Go to a doctor as soon as you can, advises Grace Marx, M.D., of the Centers for Disease Control and Prevention’s Division of Vector-Borne Disease.

Don’t wait for a rash, which doesn’t always appear. This is especially important for young children and older adults, who may be more prone to complications from tick-borne diseases. (Learn more about how to protect against tick bites.)

More on Dealing With Ticks & Mosquitoes

Blood tests can detect tick-borne diseases, but your doctor shouldn’t delay treatment while waiting for a test result if he or she suspects infection from a tick. The test for Lyme disease antibodies, for instance, isn’t very accurate until several weeks after infection—and a late diagnosis can lead to complications.

Be sure to mention to your doctor any potential contact with ticks, including while traveling, even if you don’t think you were bitten.

If you live in the Northeast or the Midwest U.S., it’s likely that most primary care doctors are familiar with Lyme disease, Marx says. But elsewhere in the country, tick-borne illnesses may not immediately spring to mind. If your doctor seems unfamiliar, consider consulting an infectious disease specialist.

Guide to Tick-Borne Diseases

The initial symptoms of most tick-borne diseases are similar. They can include fever, headache, joint swelling and muscle pain, and in some cases, gastrointestinal symptoms such as diarrhea, nausea, vomiting, or loss of appetite. A rash is a common symptom for most but not all tick-borne diseases. Anaplasmosis and babesiosis, for instance, rarely cause a rash.

When diagnosed promptly, most tick-borne diseases can be treated with a short course of antibiotics. Here’s what you need to know about some of the conditions on the rise.

Lyme Disease
Where most cases occur: Northeast, Mid-Atlantic, Pacific coast, and upper Midwest regions.

Potential complications: Brain inflammation, memory problems, palsy, and irregular heartbeat. (Since 1985, there have also been nine reported deaths from a heart infection caused by Lyme.) Most of the time, Lyme symptoms resolve after a short course of antibiotics. But in 10 to 20 percent of cases, people develop post-treatment Lyme disease syndrome, in which a variety of symptoms continue for years.

Where most cases occur:
Mid-Atlantic and Southeast to South Central regions.

Potential complications: Brain inflammation, lung or other organ failure, uncontrolled bleeding, death.

Where most cases occur: Northeast and upper Midwest regions.

Potential complications: Lung or other organ failure, bleeding problems, death.

Rocky Mountain Spotted Fever
Where most cases occur:
Eastern, Central, and Western states (especially Arkansas, Missouri, North Carolina, Oklahoma, and Tennessee).

Potential complications: Neurological problems including paralysis and mental disability, lung problems, organ damage, tissue damage that can lead to the need for limb amputation, death.

Where most cases occur:
Northeast and upper Midwest regions.

Potential complications: Bleeding problems, a severe type of anemia that leads to jaundice, organ damage, death.

Red Meat Allergy
Where most cases occur:
Southeastern states.

Potential complications: Allergic reactions can include anaphylaxis, which can be fatal. And some people develop sensitivities to items in addition to red meat, such as dairy products, gelatin, or even certain medications.

How to Keep Ticks out of Your Yard

Ticks love tall grass and cool, damp areas. On the "Consumer 101" TV show, Consumer Reports expert Catherine Roberts explains how to make your yard less inviting to these pests. 

Editor's Note: This article also appeared in the July 2019 issue of Consumer Reports magazine.