Rocky Mountain Spotted Fever

Rocky Mountain spotted fever (RMSF) is a potentially life-threatening illness you get from tick bites. The bacteria Rickettsia rickettsii (R. rickettsii) causes it.

Symptoms start out similar to many other illnesses, including headache, fever and muscle aches. If not treated right away, the bacteria attack your blood vessels, muscle cells and tissues. This can lead to leaking blood vessels, excess fluid in your tissues and damage to your muscles, nerves and organs. RMSF can be fatal or lead to lifelong health issues.

Cases of RMSF happen in the U.S., Canada, Mexico and South and Central America. Reported cases happen every month of the year. But you’re most likely to get it in warmer months, when ticks are most active.

Symptoms of Rocky Mountain spotted fever

Symptoms usually develop over a few days, starting with flu-like symptoms and getting worse. They can start two days to two weeks after an infected tick bites you.

Symptoms of Rocky Mountain fever include:

• High fever
• Headache
• Lack of appetite
• Muscle pain or soreness
• Nausea and vomiting
• Stomach pain
• Sensitivity to light
• Rash

The rash is flat and appears as red, pink, purple or dark dots or splotches. It usually starts on your wrists, forearms and ankles and spreads to other parts of your body. This can appear within a few days to a week after your first symptoms start. Some people don’t get a rash at all. Don’t wait for a rash to appear to get treatment.

Later, more severe symptoms include:

• Confusion
• Shortness of breath
• Anxiety, nervousness or agitation
• Seizures
• Numbness or weakness

Rocky Mountain spotted fever causes

The bacteria R. rickettsii causes Rocky Mountain spotted fever. You get it through the bite of an infected tick. In the U.S., the American dog tick and the Rocky Mountain wood tick are the main carriers. Other types of ticks, such as the brown dog tick, also carry RMSF in some places.

Risk factors

You’re more likely to get RMSF in the summer months, when ticks are common and people are outdoors a lot.

You’re at a higher risk for getting severely ill with RMSF if you:

• Are younger than 10 or older than 40
• Have glucose-6-phosphate dehydrogenase (G6PD) deficiency, which can weaken your red blood cells
• Have a weakened immune system

Complications

Even with antibiotic treatment, some people with Rocky Mountain spotted fever have serious or life-threatening complications. These could include:

• Acute respiratory distress syndrome (ARDS)
• Acute kidney injury
• Fluid in your lungs
• Anemia
• Heart disease
• Internal bleeding
• Sepsis
• Partial paralysis
• Loss of bowel control or bladder control
• Tissue death (gangrene) requiring amputation
• Brain inflammation (encephalitis)
• Organ failure

How doctors diagnose Rocky Mountain spotted fever

Your healthcare provider will diagnose RMSF based on a physical exam, your symptoms and whether it’s possible that you were bitten by a tick. Make sure you tell your provider if you’ve been anywhere that you could’ve encountered a tick in the past two weeks, even if you don’t remember being bitten.

Your provider can use blood and skin tests to confirm the diagnosis. But the results may not be available right away. Your provider will probably have to decide whether to treat you for RMSF before the results come back. Tests include:

• Blood tests: Your provider will take a sample of your blood to test for R. rickettsii or look for other signs of infection. Your blood usually won’t be positive for RMSF until seven to 10 days after your symptoms start. You may have to repeat blood tests later in your illness or after you recover.
• Skin tests: Your provider will use a special cutting tool called a punch (it feels like a poke or a pinch) to get a sample of your skin where you have a rash. They’ll test the sample for signs of R. rickettsii.

How is Rocky Mountain Spotted Fever treated?

Healthcare providers treat RMSF with the antibiotic doxycycline. You usually have to take it for seven to 10 days.

Treatment is most effective when it starts within five days of your symptoms appearing. If you start treatment too late, RMSF can damage your body and cause life-threatening complications.

You may need additional treatments if you’re severely ill. These could include blood transfusion, mechanical ventilation or other therapies.

Recovery time

If you start antibiotics soon after the symptoms of RMSF appear, you should feel better within a few days. You’ll still have to take antibiotics for several more days. Continue taking all medications as prescribed, even if you feel better. If your symptoms don’t improve, contact your healthcare provider right away.

When should I see my healthcare provider?

If you have a tick bite or have been in an area with ticks and have symptoms of RMSF, see your healthcare provider right away. Let them know you think you could have Rocky Mountain spotted fever.

If you have a tick bite but don’t have any symptoms, you don’t need to see your provider yet. Taking antibiotics when you’re not sick won’t help prevent RMSF. Keep an eye out for any symptoms so you can get treatment right away if they start. Not every tick bite spreads RMSF.

Go to the nearest ER if you have any of these symptoms:

• Fever over 103 degrees Fahrenheit (39.4 degrees Celsius)
• Coughing up blood
• Swollen hands or feet
• Severe stomach (abdominal) pain
• Confusion or other mental changes
• Seizures
• Numbness or weakness
• Severe vomiting

What happens if you get Rocky Mountain spotted fever?

If you receive treatment with antibiotics within days of your symptoms starting, you’re likely to recover with no lasting issues. Some people have serious complications that need treatment in a hospital.

Even after you recover, it’s possible to have long-term health issues, especially if you were very sick. These include:

• Nerve damage or paralysis
• Hearing loss
• Speech difficulties
• Vision loss
• Neurological difficulties, like balance issues or vertigo

What’s the survival rate of Rocky Mountain spotted fever?

In the U.S., the fatality (death) rate for Rocky Mountain spotted fever is 5% to 10% with treatment. It’s more likely to be fatal the later you’re treated after symptoms start. The outlook is good if treated promptly. For reasons that aren’t well understood, the fatality rate is much higher in certain countries, like Mexico and Brazil.

Can I prevent RMSF?

You can reduce your risk of Rocky Mountain spotted fever by avoiding tick bites. Tips include:

• Cut your grass regularly. Long grass (over 5 inches) attracts ticks.
• Stay on cleared paths while in wooded areas.
• Use bug sprays that have ingredients that repel ticks (such as DEET).
• Cover as much of your skin as possible with clothing when you’re in the woods or areas with long grass. Some clothing is pre-treated with tick repellent.
• Check yourself for ticks after you’ve been outside. If possible, have someone else check you in places you can’t see yourself (like your back and scalp).
• Protect your pets from ticks with treatments your veterinarian recommends. Check your pets for ticks often, especially after they’ve been outside.

Is Rocky Mountain spotted fever as bad as Lyme disease?

Rocky Mountain spotted fever and Lyme disease are both infections you get from tick bites, but they’re different illnesses. RMSF can be fatal if not treated quickly. Lyme usually isn’t life-threatening.