Symptoms and Signs of Rocky Mountain Spotted Fever

Medical Author: John P. Cunha, DO, FACOEP
Medically Reviewed on 3/11/2019

Doctor's Notes on Rocky Mountain Spotted Fever

Rocky Mountain spotted fever (RMSF) is an illness caused by the bacteria Rickettsia rickettsii that is transmitted to humans by an infected tick bite. RMSF is the most common fatal tickborne disease in the U.S.

Early symptoms of Rocky Mountain spotted fever are nonspecific and may be mistaken for other illness so it is important to alert a doctor that a tick bite has occurred. Symptoms and include fever (usually greater than 102 F), chills, nausea, vomiting, headache, muscle pain, and fatigue. About two days to two weeks after the tick bite occurs, symptoms including rash (red spots), abdominal pain, joint pains, and diarrhea develop. The rash usually begins on the wrists and ankles and spreads to the palms and soles of the feet. Other symptoms of Rocky Mountain spotted fever may include loss of appetite, hallucinations, sensitivity to light, eye redness, and excessive thirst. If RMSF is not promptly diagnosed and treated, severe symptoms may develop including low blood platelets that can lead to internal bleeding, low blood sodium, meningismus (neck stiffness, headache, and fever that may indicate brain membrane irritation), confusion, blindness, or coma that can be fatal.

Must Read Articles:


Kasper, D.L., et al., eds. Harrison's Principles of Internal Medicine, 19th Ed. United States: McGraw-Hill Education, 2015.