Rocky Mountain Spotted Fever

A rickettsial infection, transmitted to humans by animal ticks, that causes fever and a spotted rash

  • An outdoor lifestyle during summer is a risk factor in certain regions
  • Age, gender, and genetics are not significant factors

Despite its name, Rocky Mountain spotted fever occurs not only in the Rocky Mountain states of the US but also in eastern US states and South America. The disease is caused by the bacterium Rickettsia rickettsii, which is transmitted to humans through bites from infected animal ticks. Although the disease does not occur in Europe, visitors to the US who go camping or walking in woodland areas may be at risk, especially during spring and summer.

The initial symptoms appear suddenly about a week after infection and may include severe headache, muscle pains, chills, and fever. Within a few days, a rash of tiny pink spots develops, usually appearing first on the limbs and then spreading rapidly over the rest of the body. This rash gradually becomes darker. If the condition is left untreated, potentially fatal complications, such as gangrene and kidney failure, may develop.

Rocky Mountain spotted fever is usually diagnosed from the appearance of the rash, but blood tests may be carried out. If given prompt treatment with antibiotics, most infected people make a rapid recovery.

In regions known to be infested with ticks, you should wear clothes that keep your arms and legs covered to reduce the risk of being bitten (see Preventing tick bites) and promptly remove any ticks that attach themselves to your skin by pulling them off with fine-pointed tweezers or your fingernails.

Rocky Mountain spotted fever

The rash of Rocky Mountain spotted fever often begins on the limbs and spreads over the body, as seen here on the chest.

From the 2010 revision of the Complete Home Medical Guide © Dorling Kindersley Limited.

The subjects, conditions and treatments covered in this encyclopaedia are for information only and may not be covered by your insurance product should you make a claim.

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