Rocky Mountain Spotted Fever (cont.)

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What are risk factors for Rocky Mountain spotted fever?

Cases of RMSF occur when the appropriate tick vector comes in contact with human populations. Risk factors include traveling to an area with a high rate of RMSF, especially in seasons when ticks are plentiful, such as summer. People at highest risk are those who frequent forested areas or fields, such as those who are hiking or camping. Even urban outdoor areas pose a risk, however. Dog ownership is a risk factor in areas where the American dog tick exists. Dogs acquire ticks while roaming outside, and these ticks can be transferred to humans during petting or other contact.

The risk of RMSF is thought to increase with the duration of tick attachment. A feeding tick can remain attached to a human for up to two weeks. Crushing an attached tick improperly may cause secretions from the tick to be injected into the skin and increase the risk of infection.

Severe disease is more common in the elderly, alcoholics, and in African Americans. The latter is at least partly due to delays in diagnosis of the typical rash in dark-skinned people. In addition, blacks are more likely to have a genetic enzyme deficiency (G6PD) that can make the disease more severe.

What are symptoms and signs of Rocky Mountain spotted fever in children and adults?

Symptoms appear within about a week of exposure to the bacteria (range two to 14 days). Initially, people feel like they have influenza (flu) with headache, high temperature, body aches, and fatigue. Other possible symptoms include abdominal pain, vomiting, and lack of appetite. Symptoms in children may be slightly different than in adults. Children may complain less of headache and more of abdominal pain, which may be severe. The eyes may be red (conjunctivitis).

A rash appears within three to five days, often starting around the wrists or ankles and then spreading to the trunk, palms, and soles. The rash starts as discrete, small red areas and resembles the rashes (exanthems) of many other viral illnesses. Over a few days, these areas may become bright red or purple and are known as petechiae, a sign of more severe disease. The petechiae may merge as the rash advances to create a diffuse redness.

In some cases, the rash may be so mild that it is missed on examination. People with dark skin often have delayed diagnosis because the rash is harder to detect. In severe cases, the skin may turn black and necrotic (meaning there is death of tissue), resembling gangrene.

Headache is often very severe and may be the presenting complaint, especially in adults. Other neurological signs that might appear include a stiff neck, difficulty hearing, confusion, and weakness or paralysis of some muscles. Severe cases may reduce the ability of the blood to clot, which causes the patient to be at risk for internal bleeding.

None of the above symptoms is specific for RMSF. Other tick-borne illnesses may cause similar symptoms, including other members of the spotted fever rickettsiosis group. Ticks may also spread other diseases such as Lyme disease.

Picture of Rocky Mountain spotted fever rash on the hand.
Picture of Rocky Mountain spotted fever rash on the arm.
Rocky Mountain spotted fever rash pictures. SOURCE: CDC.

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Rocky Mountain Spotted Fever - Location Question: Please share your experience with RMSF, including the region in which you contracted it.
Rocky Mountain Spotted Fever - Symptoms Question: What were your signs and symptoms associated with RMSF?
Rocky Mountain Spotted Fever - Diagnosis Question: What tests or methods were used to detect and diagnose your case of RMSF?
Rocky Mountain Spotted Fever - Treatment Question: What kinds of treatment or medication did you receive for RMSF?
Rocky Mountain Spotted Fever - Prevention Question: If you live in a region with ticks or previous outbreaks of RMSF, how do you try to prevent it?

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