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Rocky Mountain Spotted Fever

Medically reviewed by Last updated on Sep 3, 2023.

What is Rocky Mountain spotted fever?

Rocky Mountain spotted fever (RMSF) is a bacterial infection caused by the bite of an infected tick. It occurs most often between April and September, when ticks are most active. RMSF can become life-threatening without treatment.

What increases my risk for RMSF?

  • A tick bite within the last 2 weeks
  • Outdoor activity in a wooded or high grass area
  • Contact with outdoor pets or wild animals

What are the signs and symptoms of RMSF?

Symptoms usually begin about 7 days after you were bitten by a tick. A rash may appear within 2 to 5 days. The rash may start as small, pink, flat dots. It may turn darker red or purple, and become bumpy. The rash usually starts on your wrists, forearms, or ankles and spreads to your palms or soles. Severe rashes may spread to your legs, chest, and abdomen. You may also have any of the following:

  • Fever above 102°F (38.9°C)
  • Headache
  • Nausea or vomiting
  • Abdominal pain
  • Loss of appetite
  • Muscle aches
  • Red eyes or eyes that are sensitive to light
  • Confusion, cough, sore throat, and diarrhea in children

How is RMSF diagnosed?

Your healthcare provider will examine you and ask about your signs and symptoms. Tell him or her about any recent outdoor activity, travel, or if you or your pets have been in wooded areas. Also tell the provider if you have seen a tick or tick bite on you, a family member, or a pet. You may need any of the following:

  • Blood tests will show your blood cell levels, liver function, and check for signs of infection.
  • A skin biopsy may be taken and sent to a lab for tests. These tests will show if the rash is caused by RMSF.

How is RMSF treated?

You may need to be monitored in a hospital if your infection is severe. You will need antibiotics to treat the infection. You may also need medicine to decrease your fever and pain.

What are the risks of RMSF?

You may develop kidney failure or breathing problems. Your blood may clot more than it should. This can keep the blood from flowing where it should in your body. RMSF may cause fluid to build up around your lungs. The bacteria can spread and infect organs or other parts of your body. RMSF may also cause swelling or damage in your liver, brain, or heart. RMSF may cause a coma if the infection is severe.

How can I prevent a tick bite?

Ticks live in areas covered by brush and grass. They may even be found in your lawn if you live in certain areas. Outdoor pets can carry ticks inside the house. Ticks can grab onto you or your clothes when you walk by grass or brush. If you go into areas that contain many trees, tall grasses, and underbrush, do the following:

  • Wear light colored pants and a long-sleeved shirt. Tuck your pants into your socks or boots. Tuck in your shirt. Wear sleeves that fit close to the skin at your wrists and neck. This will help prevent ticks from crawling through gaps in your clothing and onto your skin. Wear a hat in areas with trees.
  • Apply insect repellant on your skin. The insect repellant should contain DEET. Do not put insect repellant on skin that is cut, scratched, or irritated. Always use soap and water to wash the insect repellant off as soon as possible once you are indoors. Do not apply insect repellant on your child's face or hands.
  • Spray insect repellant onto your clothes. Use permethrin spray. This spray kills ticks that crawl on your clothing. Be sure to spray the tops of your boots, bottom of pant legs, and sleeve cuffs. As soon as possible, wash and dry clothing in hot water and high heat.
  • Check your and your child's clothing, hair, and skin for ticks. Shower within 2 hours of coming indoors. Carefully check the hairline, armpits, neck, and waist.
  • Decrease the risk for ticks in your yard. Ticks like to live in shady, moist areas. Mow your lawn regularly to keep the grass short. Trim the grass around birdbaths and fences. Cut branches that are overgrown and take them out of the yard. Clear out leaf piles. Stack firewood in a dry, sunny area.
  • Treat pets with tick control products as directed. This will decrease your risk for a tick bite. Check your pets for ticks. Remove ticks from pets the same way as you remove them from people. Ask your pet's veterinarian about the best product to use on your pet.
  • Remove a tick with tweezers. Wear gloves. Grasp the tick as close to your skin as possible. Pull the tick straight up and out. Do not touch the tick with your bare hands. Check to make sure you removed the whole tick, including the head. Clean the area with soap and water or rubbing alcohol. Then wash your hands with soap and water.

How can I manage my symptoms of RMSF?

  • Rest until you start to feel better. Return to your daily activities slowly or as directed.
  • Drink liquids as directed. You may need extra liquids to prevent dehydration. Ask how much liquid to drink each day and which liquids are best for you.

Where can I find more information?

  • Centers for Disease Control and Prevention (CDC)
    1600 Clifton Road
    Atlanta , GA 30333
    Phone: 1- 800 - 232-4636
    Web Address:

Call 911 for any of the following:

  • You have a seizure.
  • You have chest pain, trouble breathing, or a fast or pounding heartbeat.
  • You cannot be woken.

When should I seek immediate care?

  • You have a severe headache.
  • You have a swollen, hard, or tender abdomen.
  • You have swelling in your hands or legs.
  • You have trouble urinating, or you cannot urinate at all.
  • You are confused.
  • Your fever and pain do not go away in 24 hours, even after treatment.
  • You bleed from your nose or gums.
  • Your skin and the whites of your eyes turn yellow.

When should I contact my healthcare provider?

  • Your rash starts to turn black.
  • You bruise without injury.
  • You have questions or concerns about your condition or care.

Care Agreement

You have the right to help plan your care. Learn about your health condition and how it may be treated. Discuss treatment options with your healthcare providers to decide what care you want to receive. You always have the right to refuse treatment. The above information is an educational aid only. It is not intended as medical advice for individual conditions or treatments. Talk to your doctor, nurse or pharmacist before following any medical regimen to see if it is safe and effective for you.

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