Rickettsial eruptive

Rickettsial eruptiveEruptive fevers caused by bacteria of the genus Rickettsia transmitted to humans by an arthropod vector. There are 3 main groups: typhus, pimply and Far Eastern.


Demonstration of specific IgM of each group by indirect immunofluorescence. Confirmation of the diagnosis is obtained by two serological samples 10 days apart. In practice, the clinical signs and epidemiological context enough to suggest the diagnosis and start treatment.


– Symptomatic:

• Hydration (PO or IV if the patient can not drink)

• Fever: paracetamol PO. Acetylsalicylic acid (aspirin) is against-indicated because of the risk of bleeding.

– Antibiotic 1 for 7 days or until 2 days after the disappearance of fever:

doxycycline PO (except in children under 8 years and pregnant or lactating women)

Children over 8 years: 100 to 200 mg / day in one or two taken

Adult: 200 mg / day in one or two taken or chloramphenicol PO (except in pregnant or lactating women)

Children: 50 to 75 mg / kg / day in 3 divided doses

Adult: 2 g / day in 3 divided doses

– In pregnant or breastfeeding:

josamycin PO 2: 3 g / day in 3 divided doses for 8 days

– In case of epidemic typhus, doxycycline 200 mg PO in a single dose is the treatment of choice but with a higher risk of relapse.

Note: doxycycline is usually against-indicated in children under 8 years and pregnant women or nursing. However, administration of a single dose should not, in principle, induce adverse effects. Check national protocol.


– Epidemic typhus: fight against body lice.

– Murine typhus: fight against fleas and against rats.

– Spotty fevers: avoid tick bites by wearing clothing and using repellents.

– Scrub typhus: use of repellents, PO doxycycline for chemoprophylaxis (indicative, 200 mg once weekly in adults).

1* Unlike the relapsing fever, antibiotic therapy does not cause Jarish-Herxheimer reaction. However, the geographical distribution of borreliosis and rickettsioses sometimes being the same, a reaction is possible because of this association.

2* Only some macrolides are usable. Erythromycin is ineffective.

Clinical signs:

– Different forms combine common signs:

• Fever over 39 ° C with sudden onset severe headache and myalgia.

• 3 to 5 days after: the appearance of a generalized rash (see below).

• Hypotension, undissociated rapid pulse (fickle).

• tuphos combining confusion, confusion and extreme asthenia, particularly marked in typhus.

• Inoculation eschar (black spot): painless crusted lesion surrounded by a erythematous halo to the point of injection. A systematic search because it provides diagnostic orientation.

• extra-cutaneous signs vary from one form to another, are atypical and variable (see below).


– Complications can be severe, sometimes fatal: encephalitis, myocarditis, hepatitis, acute renal failure, hemorrhage, etc.