Various rickettsiae bacterial species transmitted by ixodid ticks cause spotted fever rickettsioses similar to but milder than Rocky Mountain spotted fever. Symptoms are an initial skin lesion, satellite adenopathy, and an erythematous maculopapular rash. Diagnosis is confirmed by serologic techniques or polymerase chain reaction (PCR) testing. Treatment is with doxycycline.
Spotted fever rickettsioses (caused by bacterial Rickettsiae species), other than Rocky Mountain spotted fever, include the following:
North Asian tick-borne rickettsiosis
Queensland tick typhus
African tick typhus (African tick bite fever)
Mediterranean spotted fever (boutonneuse fever)
Rickettsia parkeri rickettsiosis (transmitted by the Gulf Coast tick Amblyomma maculatum)
The causative species belong to the spotted fever group of rickettsiae. (See table .)
This image shows an adult female brown dog tick, Rhipicephalus sanguineus, which transmits Rickettsia conorii, a causative agent of boutonneuse fever.
CDC/Lauren Bishop
The epidemiology of these tick-borne rickettsioses resembles that of Rocky Mountain spotted fever (RMSF) in the Western Hemisphere. The arthropod vectors, with or without animal reservoirs, sustain rickettsial species in nature. If humans intrude accidentally into the cycle, they become infected. In certain areas, the cycle of boutonneuse fever involves domiciliary environments, with the brown dog tick, Rhipicephalus sanguineus, as the dominant vector.
Complications and death are rare except among older patients and patients who are debilitated.
Symptoms and Signs of Spotted Fever Rickettsioses
The symptoms and signs are similar for all spotted fever rickettsioses and are generally milder than with RMSF (1).
After an incubation period of 5 to 7 days, fever, malaise, headache, and conjunctival injection develop. With the onset of fever, a small eschar 2 to 5 mm in diameter appears (in boutonneuse fever, tache noire). Usually, the regional or satellite lymph nodes are enlarged. On about the fourth day of fever, an erythematous maculopapular rash appears on the forearms and extends to most of the body, including the palms and soles. Fever lasts into the second week.
CDC
A fulminant form of vasculitis can occur.
Symptoms and signs reference
1. CDC. Clinical Signs and Symptoms of Other Spotted Fever Rickettsioses. April 29, 2024. Accessed January 6, 2026.
Diagnosis of Spotted Fever Rickettsioses
History and physical examination
Biopsy of rash with antibody staining to detect organisms (eg, immunohistochemistry)
Serologic testing
Molecular diagnostic testing (polymerase chain reaction [PCR]) of a blood sample
The diagnosis of spotted fever rickettsial infections relies on timely identification of suspicious clinical signs (eg, fever, rash, eschar if present) in the appropriate epidemiologic settings (1).
Laboratory tests are used for confirmation, primarily indirect immunofluorescence assay (IFA) serology showing increased titers between acute and convalescent samples. If available, PCR testing on skin biopsies or whole blood may offer an earlier diagnosis before immunoglobulins appear.
Immunohistochemistry on formalin-fixed tissue is another adjunctive method.
For further details, see Diagnosis of Rickettsial and Related Infections.
Diagnosis reference
1. CDC. Clinical and Laboratory Diagnosis for Other Spotted Fever Rickettsioses. March 4, 2024. Accessed January 6, 2026.
Treatment of Spotted Fever Rickettsioses
Doxycycline
Treatment of spotted fever rickettsioses is doxycycline for 5 to 7 days (1).
Although some tetracyclines can cause tooth staining in children < 8 years of age, the United States Centers for Disease Control and Prevention (CDC) advises that a course of doxycycline is warranted (1). Research indicates that short courses of doxycycline (5 to 10 days, as used for rickettsial disease) can be used in children without causing tooth staining or weakening of tooth enamel (2).
Treatment references
Prevention of Spotted Fever Rickettsioses
No effective vaccine is available to prevent spotted fever rickettsioses. Measures can be taken to prevent tick bites (1).
Preventing Tick Bites
Preventing tick access to skin includes:
To avoid potential toxicity, DEET should not be used in infants under 2 months of age, and DEET concentrations ≤ 10% should be used in children under 12 years of age (2). OLE and PMD should not be used in children under 3 years of age (3). Permethrin on clothing effectively kills ticks. Frequent searches for ticks, particularly in hairy areas and on children, are essential in endemic areas. Engorged ticks should be removed with care and not crushed between the fingers because crushing the tick may result in disease transmission. The tick’s body should not be grasped or squeezed. Gradual traction on the head with a small forceps dislodges the tick. The point of attachment and the person's hands should be disinfected with soap and water, rubbing alcohol, or hand sanitizer. Petroleum jelly, lit matches, and other irritants are not effective ways to remove ticks and should not be used. Complete elimination of tick populations is often not practically possible over large areas, but they may be reduced in certain zones (eg, residential) within endemic areas. To create a tick-safe residential environment, it is necessary to eliminate tick habitats and restrict host entry by clearing brush, tall grasses, and accumulated debris from around homes and lawn edges (1). Regular lawn maintenance, including frequent mowing and the installation of a 3-foot wide barrier of wood chips or gravel between lawns and wooded areas, is recommended to restrict tick migration into recreational zones. To reduce the presence of disease-carrying rodents (eg, rats, mice) and wildlife (eg, deer, raccoons), firewood may be stacked in dry, elevated areas. Physical fencing can also be installed. Recreational equipment and outdoor seating should be removed from shaded yard edges as should accumulated yard clutter to eliminate the potential for tick harborage. |
Prevention references
1. Centers for Disease Control and Prevention (CDC). Preventing Tick Bites. August 28, 2024. Accessed January 5, 2026.
2. Ho BM, Davis HE, Forrester JD, et al. Wilderness Medical Society Clinical Practice Guidelines for the Prevention and Management of Tick-Borne Illness in the United States. Wilderness Environ Med. 2021;32(4):474-494. doi:10.1016/j.wem.2021.09.001
3. CDC. Mosquitoes, Ticks, and Other Arthropods. April 23, 2025. Accessed March 5, 2026.
Drug Information for the Topic
