Approach Considerations
Early treatment is critical to the outcome in Rocky Mountain spotted fever (RMSF) and must be started on the basis of clinical diagnosis. [2] Consider the possibility of RMSF and promptly begin antibiotic treatment in any patient with potential tick exposure who develops fever, myalgia, or headache, even if they do not have a rash.
Never delay treatment while awaiting a confirmatory laboratory diagnosis or the development of a rash. The best outcomes are achieved when treatment is started within 5 days of symptom onset, and the classic petechial rash may not appear until day 6.
Doxycycline
Doxycycline is considered to be first-line treatment for both adults and children and should be started as soon as RMSF is suspected. [14] The use of any other antibiotics has been associated with a higher risk of death (see Table 2, below).
Doxycycline treatment is most effective at preventing death if it is started within the first 5 days after symptoms begin. As a result, doxycycline treatment should be started before the return of laboratory results and before the manifestation of severe symptoms, such as petechiae. If the patient is treated within the first 5 days of disease, fever generally subsides within 24-72 hours. [14]
The recommended dosage of doxycycline is 2.2 mg/kg body weight twice daily for children less than 45 kg (100 lb). For adults, the dosage is 100 mg every 12 hours. Patients should be treated for at least 3 days after the fever subsides and until there is evidence of clinical improvement. Standard duration of treatment is 7-14 days.
The recommended dosage of doxycycline for RMSF has not been shown to cause staining of permanent teeth. [15]
Chloramphenicol was previously recommended for the treatment of children younger than 9 years. In national surveillance data, however, patients treated with chloramphenicol were more likely to die than those treated with a tetracycline. Staining of teeth caused by one or more courses of tetracyclines (particularly doxycycline) is negligible.
Some authors have advocated the use of adjunctive corticosteroids, but the specific therapeutic benefits of these drugs are not known. Physicians should be aware that sulfonamide treatment given empirically in a febrile child can worsen Rocky Mountain spotted fever.
Other supportive measures (eg, intravenous administration of fluids, oxygenation, correction of electrolyte impairments, management of disseminated intravascular coagulation) should be provided according to the patient's clinical situation.
Patients with RMSF should be treated in consultation with an infectious disease specialist.
Deterrence and Prevention
Avoidance of tick-infested areas is the first line of defense against RMSF. If tick-infested areas cannot be avoided, wearing light-colored shirts and trousers that fit tightly around the waist and ankles can minimize the risk of being bitten.
Exposed areas of the skin should be covered with insect repellents containing N -N -diethyl-M -toluamide (DEET). In children, insect repellents should be used carefully on exposed skin. Application to the face and hands should be avoided.
After people leave an endemic area, they should inspect their bodies for attached ticks, with particular attention to areas containing hair.
If ticks are found, any of several commercial removal devices should be used if possible. Otherwise, ticks should be removed by grasping them with fine tweezers at the point of attachment and by pulling them out slowly and steadily. The aim is to remove the tick's mouthparts from the site of insertion without damaging the body of the tick.
After the tick is removed, the skin should be disinfected. Check to make sure that the head of the tick is not still embedded.
Some have recommended keeping the removed tick in a jar along with a dampened paper towel in the refrigerator for a month. This way, if the person later develops symptoms, the tick may be used to help identify what (if any) infection it may have transmitted.
Burning the tick, smothering it in alcohol or petroleum jelly (or another substance), or twisting or rubbing it off is not recommended. These methods have not been shown to decrease the time the tick remains embedded. In addition, they may pose of risk breaking the body of the tick open and releasing bacteria that were otherwise contained within it.
After a tick bite occurs, use of antimicrobial prophylaxis has no role in the prevention of RMSF.
Table: Specific Recommended Treatment
Table 2. Doxycycline Treatment for Rocky Mountain Spotted Fever (Open Table in a new window)
|
-
Geographic distribution of Rocky Mountain spotted fever incidence in 2010, cases per million: Courtesy of the US Centers for Disease Control and Prevention.
-
Annual incidence (per million persons) for Spotted Fever Rickettsiosis (SFR) in the United States, 2017. Courtesy of the CDC.
-
Under a magnification of 98X, this scanning electron microscopic (SEM) image depicts the dorsal view of the head region from an American dog tick, Dermacentor variabilis, magnified 98X. D. variabilis is a known carrier of Rocky Mountain Spotted Fever (RMSF) caused by the bacterium, Rickettsia rickettsii. Courtesy of the Public Health Image Library (PHIL), CDC, photo credit Janice Haney Carr.
-
Rocky Mountain Spotted Fever (RMSF) rash in a child. It appears day 3-5 of illness, begins in ankles and wrists, and typically involves palms and soles. In early stages it is macular and later it is petechial. Courtesy of the Morbidity and Mortality Weekly Report (MMWR), CDC.
-
Tick identification. (i) American dog tick (Dermacentor variabilis), ii) Rocky Mountain wood tick (Dermacentor andersoni), and, iii) brown dog tick (Rhipicephalus sanguineus) iv) Lone star tick (Amblyomma americanum). Courtesy of the CDC.
Tables
Organism |
Disease or Presentation |
Geographic Location |
Rickettsia rickettsii |
Rocky Mountain spotted fever |
North, Central and South America |
Rickettsia akari |
Rickettsialpox |
Worldwide |
Rickettsia conorii |
Mediterranean spotted fever, boutonneuse fever, Israeli spotted fever, Astrakhan fever, Indian tick typhus |
Europe, Asia, Africa, India, Israel, Sicily, Russia |
Rickettsia sibirica |
Siberian tick typhus, North Asian tick typhus |
Siberia, People's Republic of China, Mongolia, Europe |
Rickettsia australis |
Queensland tick typhus |
Australia |
Rickettsia honei |
Flinders Island spotted fever, Thai tick typhus |
Australia, South Eastern Asia |
Rickettsia africae |
African tick-bite fever |
Sub Saharan Africa, Caribbean |
Rickettsia japonica |
Japanese or Oriental spotted fever |
Japan |
Rickettsia felis |
Cat flea rickettsiosis, flea borne typhus |
Worldwide |
Rickettsia slovaca |
Necrosis, erythema, lymphadenopathy |
Europe |
Rickettsia heilongjaiangensis |
Mild spotted fever |
China, Asian region of Russia |
Rickettsia parkeri |
Mild spotted fever |
US |
|
