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Home :: Spotted Fevers
Spotted Fevers
The spotted fevers include Rocky Mountain spotted fever (RMSF), tick typhus, and rickettsialpox and are characterized by an exanthem and fever. All, except for rickettsialpox, are transmitted to humans by the bite of ixodid ticks. Clinically, the spectrum of severity of clinical findings is broad, ranging from mild symptoms of general malaise and an exanthem to life-threatening illness.
Causes of Spotted Fevers
Rickettsiae reproduce within endothelial cells at the bite site; the subsequent injury results in dermal and epidermal necrosis and perivascular edema, which presents clinically as a papule that evolves to a crusted ulcer at the bite site (tache noire or eschar). Rickettsiae then seed from this site into blood and systemically. In severe cases, disseminated vascular infection occurs with meningoencephalitis and vascular lesions in kidneys, lungs, GI tract, liver, pancreas, heart, spleen, and skin.
Symptoms of Spotted Fevers
Initial symptoms may include:
- fever
- nausea
- emesis
- severe headache
- muscle pain
- lack of appetite
Later signs and symptoms include:
- maculopapular rash
- petechial rash
- abdominal pain
- joint pain
- sdiarrhea
Diagnosis
Epidemiologic and clinical findings with identification of a tache noire confirmed by demonstration of rickettsiae by immunohistologic techniques in lesional skin biopsy specimens and/or serology. In an endemic area, patients presenting with fever, rash, and/or a skin lesion consisting of a black necrotic area or a crust surrounded by erythema should be considered to have one of the rickettsial spotted fevers.
Treatment
Antirickettsial Therapy Specific antirickettsial therapy abbreviates the length and severity of illness, i.e., spotted fevers, tick typhus, and rickettsialpox.
Drug of Choice Doxycycline, 100 mg PO bid for 1 to 5 days.
Alternatives Ciprofloxacin, 750 mg PO bid for 5 days or chloramphenicol, 500 mg PO qid for 7 to 10 days or josamycin (in pregnancy), 3 g/d PO for 5 days.
Prevention
Control host animals and vectors.
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