Skip to main content
Update Location

My Location

Update your location to show providers, locations, and services closest to you.

Enter a zip code
Or
Select a campus/region
(352) 733-0111

Colorado tick fever

Definition

Colorado tick fever is a viral infection. It is spread by the bite of the Rocky Mountain wood tick (Dermacentor andersoni).

Alternative Names

Mountain tick fever; Mountain fever; American mountain fever

Causes

This disease is usually seen between March and September. Most cases occur in April, May, and June.

Colorado tick fever is seen most often in the western United States and Canada at elevations higher than 4,000 feet (1,219 meters). It is transmitted by a tick bite or, in very rare cases, by a blood transfusion.

Symptoms

Symptoms of Colorado tick fever most often start 1 to 14 days after the tick bite. A sudden fever continues for 3 days, goes away, then comes back 1 to 3 days later for another few days. Other symptoms include:

  • Feeling weak all over and muscle aches
  • Headache behind the eyes (typically during fever)
  • Lethargy (sleepiness) or confusion
  • Nausea and vomiting
  • Rash (may be light colored)
  • Sensitivity to light (photophobia)
  • Skin pain
  • Sweating

Exams and Tests

The health care provider will examine you and ask about your signs and symptoms. If the provider suspects you have the disease, you will also be asked about your outdoor activity.

Blood tests will usually be ordered. Antibody tests can be done to confirm the infection. Other blood tests may include:

Treatment

There are no specific treatments for this viral infection.

The provider will make sure the tick is fully removed from the skin.

You may be told to take a pain reliever if you need it. DO NOT give aspirin to a child who has the disease. Aspirin has been linked with Reye syndrome in children. It may also cause other problems in Colorado tick fever.

If complications develop, treatment will be aimed at controlling the symptoms.

Outlook (Prognosis)

Colorado tick fever usually goes away by itself and is not dangerous.

Possible Complications

Complications may include:

  • Infection of the membranes covering the brain and spinal cord (meningitis)
  • Irritation and swelling of the brain (encephalitis)
  • Repeated bleeding episodes for no apparent cause

Call your provider if you or your child develops symptoms of this disease, if symptoms worsen or do not improve with treatment, or if new symptoms develop.

When to Contact a Medical Professional


Prevention

When walking or hiking in tick-infested areas:

  • Wear closed shoes
  • Wear long sleeves
  • Tuck long pants into socks to protect the legs

Wear light-colored clothing, which shows ticks more easily than darker colors. This makes them easier to remove.

Check yourself and your pets frequently. If you find ticks, remove them right away by using tweezers, pulling carefully and steadily. Insect repellent may be helpful.

Gallery

Lyme disease
Having a tick attached to your body isn't just getting a little too close to nature. The tick can make you seriously ill with Lyme disease. Lyme disease is caused by bacteria called Borrelia burgdorferi. Blacklegged ticks carry these bacteria. The ticks pick up the bacteria when they bite mice or deer that are infected with Lyme disease. You can get the disease if you are bitten by an infected tick, mostly in northeastern states and on the West Coast. The good news is that usually a tick has to be attached to your body for 24 to 36 hours to infect you. The bad news is that blacklegged ticks are so small they're almost impossible to see. Many people with Lyme disease never even see a tick on their body. But most people bitten by a tick do NOT get Lyme disease. So, how do you know for sure that you have Lyme disease? The flu-like symptoms of Lyme disease usually start days or weeks after you've been bitten. You might have Itching all over your body; Chills, fever, and light headedness; Or perhaps a Headache, muscle pain, and a stiff neck. You'll probably see a bull's eye rash on your body. It can get pretty big. After a few weeks, the muscles in your face might feel weak or even paralyzed. Your knees and other joints may swell and hurt. You might even notice your heart skipping some beats. Eventually, your muscles might move strangely, you may feel numbness or tingling, and you may start to have trouble speaking. A doctor will test your blood for antibodies that are trying to fight the bacteria in your blood. One of these tests is called the ELISA test, and you'll often have a second test called the Western blot test to confirm you have Lyme disease. To treat Lyme disease, you may need to take antibiotics for up to a month. Pain medicines from the drug store can help soothe your joint stiffness. If it's caught early, Lyme disease is pretty easily treated. Without treatment, you can have heart, muscle, and even nerve problems. So the next time you're out in the woods or high grass, wear protective clothing, and do check yourself for ticks once you get home.
Lyme disease
The most common early sign of lyme disease is the appearance of a rash on the skin that looks like a bulls eye. The rash begins as a reddened area near the area of the tick bite. As the rash gets bigger, it clears in the center and develops a red ring around the outer perimeter. Other symptoms include muscle or joint aches, stiff neck, headache, weakness, fever, swollen lymph nodes and other flu-like symptoms.
Stomach
The stomach is the portion of the digestive system most responsible for breaking down food. The lower esophageal sphincter at the top of the stomach regulates food passing from the esophagus into the stomach, and prevents the contents of the stomach from reentering the esophagus. The pyloric sphincter at the bottom of the stomach governs the passage of food out of the stomach into the small intestine.
Lyme disease
Having a tick attached to your body isn't just getting a little too close to nature. The tick can make you seriously ill with Lyme disease. Lyme disease is caused by bacteria called Borrelia burgdorferi. Blacklegged ticks carry these bacteria. The ticks pick up the bacteria when they bite mice or deer that are infected with Lyme disease. You can get the disease if you are bitten by an infected tick, mostly in northeastern states and on the West Coast. The good news is that usually a tick has to be attached to your body for 24 to 36 hours to infect you. The bad news is that blacklegged ticks are so small they're almost impossible to see. Many people with Lyme disease never even see a tick on their body. But most people bitten by a tick do NOT get Lyme disease. So, how do you know for sure that you have Lyme disease? The flu-like symptoms of Lyme disease usually start days or weeks after you've been bitten. You might have Itching all over your body; Chills, fever, and light headedness; Or perhaps a Headache, muscle pain, and a stiff neck. You'll probably see a bull's eye rash on your body. It can get pretty big. After a few weeks, the muscles in your face might feel weak or even paralyzed. Your knees and other joints may swell and hurt. You might even notice your heart skipping some beats. Eventually, your muscles might move strangely, you may feel numbness or tingling, and you may start to have trouble speaking. A doctor will test your blood for antibodies that are trying to fight the bacteria in your blood. One of these tests is called the ELISA test, and you'll often have a second test called the Western blot test to confirm you have Lyme disease. To treat Lyme disease, you may need to take antibiotics for up to a month. Pain medicines from the drug store can help soothe your joint stiffness. If it's caught early, Lyme disease is pretty easily treated. Without treatment, you can have heart, muscle, and even nerve problems. So the next time you're out in the woods or high grass, wear protective clothing, and do check yourself for ticks once you get home.

References

Bolgiano EB, Sexton J. Tick-borne illnesses. In: Walls RM, Hockberger RS, Gausche-Hill M, eds. Rosen's Emergency Medicine: Concepts and Clinical Practice. 9th ed. Philadelphia, PA: Elsevier; 2018:chap 126.

Dinulos JGH. Infestations and bites. In: Dinulos JGH, ed. Habif's Clinical Dermatology. 7th ed. Philadelphia, PA: Elsevier; 2021:chap 15.

Naides SJ. Arboviruses causing fever and rash syndromes. In: Goldman L, Schafer AI, eds. Goldman-Cecil Medicine. 26th ed. Philadelphia, PA: Elsevier; 2020:chap 358.

Last reviewed December 24, 2020 by Jatin M. Vyas, MD, PhD, Assistant Professor in Medicine, Harvard Medical School; Assistant in Medicine, Division of Infectious Disease, Department of Medicine, Massachusetts General Hospital, Boston, MA. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team..

Related specialties