Rocky Mountain Spotted Fever

What is Rocky Mountain spotted fever?

Rocky Mountain spotted fever (RMSF) is an infection caused by the bite of an infected tick. It affects over 2,000 people a year in the U.S. and usually occurs from April until September. But, it can occur anytime during the year where the weather is warm. It was first recognized in the Rocky Mountain states, but may occur throughout the U.S. Most common areas affected are in the southeastern and south central U.S. The disease is spread to humans through a bite from an infected tick. It is not spread from person to person.

What causes Rocky Mountain spotted fever?

RMSF is caused by a bacterium that is spread to people by the bite of an infected tick. In the U.S., the American dog tick, the Rocky Mountain wood tick, and the brown dog tick are the ticks that transmit the RMSF bacteria.

Who is at risk for Rocky Mountain spotted fever?

People living in or visiting areas where ticks are prevalent, particularly the southeastern and south central U.S., are at risk for Rocky Mountain spotted fever.

What are the symptoms of Rocky Mountain spotted fever?

The following are the most common symptoms of RMSF:

  • A non-itchy rash that usually starts on the hands, arms, feet, and legs and occurs 5 to 10 days after the bite. The rash consists of flat, pink spots.
  • Fever
  • Headache
  • Confusion
  • Decreased appetite
  • Chills
  • Sore throat
  • Stomachache
  • Nausea or vomiting
  • Diarrhea
  • Body aches
  • Sensitivity to light

RMSF is a serious illness that needs treatment as soon as possible. Death has occurred in untreated cases of RMSF.

Symptoms of RMSF may look like other conditions or medical problems. See a healthcare provider for diagnosis.

How is Rocky Mountain spotted fever diagnosed?

Diagnosis is based on symptoms and history of a tick bite. How the rash looks is important. Skin samples and lab tests are usually done to rule out other conditions and confirm the diagnosis.

How is Rocky Mountain spotted fever treated?

Specific treatment for Rocky Mountain spotted fever will be determined by your healthcare provider based on the following:

  • How old you are
  • Your overall health and medical history
  • How sick you are
  • How well you can handle specific medicines, procedures, or therapies
  • How long the condition is expected to last
  • Your opinion or preference
Treatment may include antibiotics (usually doxycycline) until several days after the fever goes away. Efforts to relieve symptom also helps.

What are the complications of Rocky Mountain spotted fever?

RMSF can be cured when treated with antibiotics. However, if untreated, serious complications can occur including:

  • Nerve damage
  • Hearing loss
  • Incontinence
  • Partial paralysis
  • Tissue death (gangrene) of toes or fingers
  • Rarely, death

Can Rocky Mountain spotted fever be prevented?

Once you’ve had RMSF, you can’t get it again. To help prevent RMSF, follow these guidelines.


Ticks can't bite though clothing, so dress in:

  • Light-colored clothing (so you can spot ticks on clothing easier)
  • Long-sleeved shirts tucked into pants
  • Socks and closed-toe shoes
  • Long pants with legs tucked into socks

Checking for ticks

It's important to check often for ticks, especially on these parts of the body:

  • Around the joints: behind the knees, between fingers and toes, underarms, and groin
  • Other areas where ticks are commonly found: belly button, in and behind the ears, neck, hairline, and top of the head
  • Areas of pressure points, including anywhere that clothing presses tightly on the skin
  • All other areas of the body and hair. Run your fingers gently over the skin, and run a fine-toothed comb through your hair to check for ticks.

Insect repellent

Be sure to use any insect repellents safely.

  • Products that contain DEET are tick repellents, but may not kill the tick and are not 100% effective. For children, use a children's insect repellent (20% to 30% DEET). Check with your child's healthcare provider if your child is younger than age 1 before using.
  • Treat clothing with a product that contains permethrin, which is known to kill ticks on contact. Don't use permethrin on skin.

Other measures

The following may also be helpful:

  • When possible, walk on cleared paths and pavement through wooded areas and fields.
  • Shower after all outdoor activities are over for the day. It may take up to 4 to 6 hours for ticks to attach firmly to skin. Showering may help remove any loose ticks.
  • Check pets for ticks and treat as needed.

When should I call my healthcare provider?

If your symptoms get worse or you have new symptoms, let your healthcare provider know.

Key points about Rocky Mountain spotted fever

  • RMSF is caused by a bacterium that is spread to people by the bite of an infected tick.
  • Symptoms include a rash, fever, headache, decreased appetite, chills, sore throat, confusion, stomach ache, nausea or vomiting, diarrhea, body aches, and sensitivity to light.
  • Treatment includes antibiotics and symptom relief.
  • If untreated, serious complications, including nerve damage, hearing loss, incontinence, partial paralysis, and gangrene of toes or fingers, can occur.

Next steps

Tips to help you get the most from a visit to your healthcare provider:

  • Know the reason for your visit and what you want to happen.
  • Before your visit, write down questions you want answered.
  • Bring someone with you to help you ask questions and remember what your provider tells you.
  • At the visit, write down the name of a new diagnosis, and any new medicines, treatments, or tests. Also write down any new instructions your provider gives you.
  • Know why a new medicine or treatment is prescribed, and how it will help you. Also know what the side effects are.
  • Ask if your condition can be treated in other ways.
  • Know why a test or procedure is recommended and what the results could mean.
  • Know what to expect if you do not take the medicine or have the test or procedure.
  • If you have a follow-up appointment, write down the date, time, and purpose for that visit.
  • Know how you can contact your provider if you have questions.

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