logo

DermNet NZ

Ad

Facts about skin from the New Zealand Dermatological Society Incorporated. Topic index: A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

Balamuthia mandrillaris infection

Balamuthia mandrillaris (B. mandrillaris) is an amoeba first discovered in 1990 and associated with more than 100 cases of disease since. Infection with B. mandrillaris has been reported in South, Central, and North America, Asia, Australia, and Europe but remains a rare cause of amoebiasis.

B. mandrillaris lives in water and soil and can enter humans through the nasal mucosa, lungs, or breaks in the skin. As in cases of other free-living amoebae (e.g. Naegleria and Acanthamoeba), a history of swimming in freshwater lakes, ponds, and heated swimming pools seems to be common.

Weeks to years later (5 to 8 months on average) the infection spreads to the central nervous system causing amoebic encephalitis (inflammation of the brain). Features include:

In 95% of patients, B. mandrillaris encephalitis is fatal.

How does it affect the skin?

The dermatological significance of B. mandrillaris is that a typical skin lesion appears before the infection spreads to the central nervous system. The classical skin lesion is an asymptomatic granulomatous plaque (a nodule made of inflammatory cells), usually located on the central face.

The lesion may enlarge (to involve the entire face in some cases), and occasionally gives origin to smaller satellite lesions. Ulceration occurs at a late stage. Occasionally the lesion may occur on the extremities.

Treatment

Early treatment with a range of oral antifungal, anthelmintic, and antiprotozoal drugs may improve survival.

Related information

References:

On DermNet NZ:

Other websites:

Books about skin diseases:

See the DermNet NZ bookstore

Author: Marie Hartley, staff writer.

DermNet does not provide an on-line consultation service.
If you have any concerns with your skin or its treatment, see a dermatologist for advice.