Ask the Doctors by Eve Glazier, M.D. and Elizabeth Ko, M.D

Keep Vigilant to Prevent Rocky Mountain Spotted Fever

Dear Doctor: My wife and I appreciate your articles about ticks, and we wonder if you could talk about Rocky Mountain spotted fever? A friend of ours here in Arkansas got really sick from it, and since our family is big on outdoor activities, we want to know what to look for.

Dear Reader: We’re glad the information about tick-borne infections and illnesses has been useful. We get quite a few questions on the topic, which reflects the growing awareness of ticks and the health dangers associated with them.

Rocky Mountain spotted fever, or RMSF, is a potentially deadly disease acquired when an individual is bitten by a tick infected with the bacterium Rickettsia rickettsii. Depending on the region, the disease is spread by the Rocky Mountain wood tick, the American dog tick or the brown dog tick. Although it has been found across wide areas of the United States, Rocky Mountain spotted fever is most often reported in Oklahoma, North Carolina, Missouri, Tennessee and in your home state of Arkansas. It can also be found in parts of the American Southwest and in Mexico.

As with many tick-borne diseases, initial signs of RMSF can be general enough that they are easily attributed to other causes, including a cold or the flu. Symptoms commonly include fever, headache, abdominal pain, nausea, vomiting and lethargy. The rash that usually accompanies RMSF often develops between two and four days after the initial infection, which adds to the challenge of a swift and accurate diagnosis. The rash can take a variety of forms, from bold red splotches to tiny pinpoint dots.

Although a laboratory test is needed to confirm RMSF, the Centers for Disease Control and Prevention urge health care providers to commence immediate treatment when clinical signs and symptoms, as well as a thorough health and travel history, point to the disease. Immediate treatment is crucial in cases of Rocky Mountain spotted fever, and waiting for confirmation from a lab test can put the patient at risk.

The recommended treatment for RMSF is the antibiotic doxycycline. Early treatment can prevent serious illness and death. When left untreated, the bacterium that causes Rocky Mountain spotted fever can cause extensive damage to blood vessels throughout the body, which leads to tissue and organ damage. Death can occur in as little as eight days after the onset of symptoms. At this time, there is no vaccine for RMSF, which makes prevention the only way to avoid infection.

Summer is high season for ticks. These tiny arachnids can be as small as a poppy seed early on in their life cycle, and since a tick bite is usually painless, ongoing vigilance is key. At the risk of repeating ourselves, this includes avoiding densely wooded and brushy areas, covering exposed skin with light-colored clothes, wearing closed-toed shoes, tucking pants into socks, using appropriate pesticides and doing visual body scans, including of pets. And check into local resources. Many communities throughout the U.S. have vector control agencies, which are devoted to the identification and control of dangerous local pests, including ticks.

(Send your questions to, or write: Ask the Doctors, c/o UCLA Health Sciences Media Relations, 10880 Wilshire Blvd., Suite 1450, Los Angeles, CA, 90024. Owing to the volume of mail, personal replies cannot be provided.)