Rickettsial pox

Definition

Rickettsial pox is an infectious disease spread by a mite and characterized by a chickenpox-like rash.

Causes, incidence, and risk factors

Rickettsial pox is caused by Rickettsia akari. It is commonly found in the United States in New York City and other city areas. It also has been seen in South Africa, Korea, and Russia. It is spread by the bite of a mite which lives on mice (Liponyssoides sanguineus).

The disease begins at the site of the mite bite as a painless, firm, red nodule that develops into a fluid-filled blister that bursts and crusts over. This lesion may be large -- almost up to an inch wide.

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 that looks like chickenpox develops. This rash clears up within a week.

Symptoms

• Painless, firm, red nodule that develops into a fluid-filled blister that bursts and crusts over, may be an inch wide
• Fever and chills
• Sweating (diaphoresis)
• Muscle pain (myalgia)
• Rash that looks like chicken pox
• Discomfort when in bright light (photophobia)

Signs and tests

Physical examination confirms the presence of a rash that resembles chicken pox.

Tests include:

• Serologic studies demonstrate antibody titers to Rickettsia akari
• CBC

Treatment

The goal of treatment is to cure the infection. Medications used include antibiotics such as chloramphenicol, tetracycline, and doxycycline.

Expectations (prognosis)

Full recovery is expected.

Complications

There are usually no complications if the disorder is treated.

Calling your health care provider

Call your health care provider if your child has symptoms suggestive of rickettsial pox.

Prevention

Sanitary measures, especially with regard to control of mice and their parasites, will prevent spread of rickettsialpox.