Various rickettsiae 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.

Spotted fever rickettsioses include North Asian tick-borne rickettsiosis, Queensland tick typhus, African tick typhus, and Mediterranean spotted fever (boutonneuse fever). The causative agents belong to the spotted fever group of rickettsiae.

The epidemiology of these tick-borne rickettsioses resembles that of Rocky Mountain spotted fever (RMSF) in the Western Hemisphere. Ixodid ticks and wild animals maintain the rickettsiae 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.

Symptoms and Signs

The symptoms and signs are similar for all spotted fever rickettsioses and generally milder than with RMSF. After an incubation period of 5 to 7 days, fever, malaise, headache, and conjunctival injection develop. With the onset of fever, a small buttonlike ulcer 2 to 5 mm in diameter with a black center appears (an eschar or, in boutonneuse fever, tache noire). Usually, the regional or satellite lymph nodes are enlarged. On about the 4th day of fever, a red maculopapular rash appears on the forearms and extends to most of the body, including the palms and soles. Fever lasts into the 2nd wk.

Complications and death are rare except among elderly or debilitated patients. However, the disease should not be ignored; a fulminant form of vasculitis can occur.

Diagnosis

For diagnosis, see Rickettsiae and Related Organisms: Diagnosis.

Treatment

• DoxycyclineSome Trade Names
  PERIOSTAT
  VIBRAMYCIN
  Click for Drug Monograph
  or ciprofloxacinSome Trade Names
  CILOXAN
  CIPRO
  Click for Drug Monograph
  

Treatment is doxycyclineSome Trade Names
PERIOSTAT
VIBRAMYCIN
Click for Drug Monograph
100 mg po bid for 5 days or ciprofloxacinSome Trade Names
CILOXAN
CIPRO
Click for Drug Monograph
500 to 750 mg po bid for 5 days. Measures can be taken to prevent tick bites (see Sidebar 1: Rickettsiae and Related Organisms: Tick Bite Prevention).

Sidebar 1
Tick Bite Prevention
Preventing tick access to skin includes Staying on paths and trails Tucking trousers into boots or socks Wearing long-sleeved shirts Applying repellents with diethyltoluamide (DEET) to skin surfaces DEET should be used cautiously in very young children because toxic reactions have been reported. PermethrinSome Trade Names ELIMITE NIX RID SPRAY Click for Drug Monograph 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 should be swabbed with alcohol. Petroleum jelly, alcohol, lit matches, and other irritants are not effective ways to remove ticks and should not be used. No practical means are available to rid entire areas of ticks, but tick populations may be reduced in endemic areas by controlling small-animal populations.

Last full review/revision November 2012 by William A. Petri, Jr., MD, PhD

Content last modified December 2012