Rickettsial pox

Definition:

An infectious diseases transmitted by a mite and characterized by a chickenpox-like rash.

Causes, incidence, and risk factors:

Rickettsialpox is caused by Rickettsia akari and is commonly found (endemic) in the United States in New York City and other large eastern cities. It is transmitted by a mouse mite (Allodermanyssus sanguineus) and is found throughout the U.S.

The disease begins at the site of the mite bite as a nontender firm red nodule that develops into a vesicle (fluid-filled blister) which then bursts and crusts over. This lesion may be large, almost up to an inch across. Several days later, the patient develops a fever and chills with sweating (diaphoresis) and muscle pain (myalgia). Over the next 2 to 3 days, a rash develops with many small versions of the initial lesion and resembling the chickenpox rash in nature. These lesions clear up within a week.