Rocky Mountain spotted fever is the most severe and most frequently reported rickettsial illness in the United States. It also occurs in Mexico and in Central and South America.
The disease is caused by Rickettsia rickettsii, a species of bacteria that is spread to humans by ticks. Initial signs and symptoms of the disease include sudden onset of fever, headache, and muscle pain, followed by development of rash.
The disease can be difficult to diagnose in the early stages, and without prompt and appropriate treatment it can be fatal.
Initial symptoms may include fever, nausea, vomiting, severe headache, muscle pain, lack of appetite.
The rash first appears 2—5 days after the onset of fever and is often not present or may be very subtle when the patient is initially seen by a physician. Younger patients usually develop the rash earlier than older patients. Most often it begins as small, flat, pink, non-itchy spots (macules) on the wrists, forearms, and ankles. These spots turn pale when pressure is applied and eventually become raised on the skin.
Later signs and symptoms include rash, abdominal pain, joint pain, diarrhea.
The characteristic red, spotted (petechial) rash of Rocky Mountain spotted fever is usually not seen until the sixth day or later after onset of symptoms, and this type of rash occurs in only 35% — 60% of patients with Rocky Mountain spotted fever. The rash involves the palms or soles in as many as 50%— 80% of patients; however, this distribution may not occur until later in the course of the disease. As many as 10% — 15% of patients may never develop a rash.
Long-term health problems following acute Rocky Mountain spotted fever infection include partial paralysis of the lower extremities, gangrene requiring amputation of fingers, toes, or arms or legs, hearing loss, loss of bowel or bladder control, movement disorders, and language disorders. These complications are most frequent in persons recovering from severe, life-threatening disease, often following lengthy hospitalizations.