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MM 355-356; ID 975-977


DISEASE NAME:     Rickettsialpox

ETIOLOGICAL AGENT:    Rickettsia akari


This is a benign disease, mainly of adults, that is transmitted to man by a mite (Liporyssoides sanguine). The mouse (Mus musculus) is a definitive host. It is an urban disease.


The primary, or herald lesion, occurs at the site of the bite after one-two weeks. The lesion forms a black eschar and inflammation is intense in the deeper layer of the dermis, where there is actual necrosis. There is a septicemia and ensuing generalized rash. The rash is vesicular papular. The vesicles are small and they appear to be embedded in the papule.


The diagnosis may be made by:

    1. Serology

    2. Herald lesion

    3. Urban setting

    4. Fever which precedes the rash

    5. The vesicle which is only the central part of the papule

    6. Definite prodrome

    7. Rash is evenly distributed except for palms, soles, and mucous membranes

    8. Single crop of lesions all at the same stage except for herald lesion


Doxycycline (sulfonamides contraindicated)

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