MedlinePlus Medical Encyclopedia: Swimming pool granuloma

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Swimming pool granuloma

Contents of this page:
Alternative Names Definition Causes Symptoms Exams and Tests	Treatment Outlook (Prognosis) Possible Complications When to Contact a Medical Professional Prevention

Alternative Names

Aquarium granuloma; Fishtank granuloma

Definition Return to top

A swimming pool granuloma is a chronic skin infection caused by the bacteria Mycobacterium marinum.

Causes Return to top

A swimming pool granuloma results when water containing an infectious organism, Mycobacterium marinum, enters a break in the skin. A localized infection called a granuloma results after about 3 weeks.

Symptoms Return to top

The person usually has a history of exposure to swimming pools, salt water aquarium, or ocean fish.

The lesions appear as reddish bumps (papules) that slowly grow into purplish nodules.

The elbows, fingers, back of the hands, and knees are the most common sites affected. The nodules may break down and leave an open sore, or spread up the limb.

Exams and Tests Return to top

A skin biopsy and culture is usually needed to confirm the diagnosis. A PPD tuberculin skin test will usually be positive.

Treatment Return to top

Antibiotics are used to treat this infection. Several months of treatment are often needed.

Outlook (Prognosis) Return to top

Swimming pool granulomas can usually be treated completely with antibiotics.

Possible Complications Return to top

Occasionally, joint or bone infections occur. Patients with defective immune systems may also have longer or more complicated cases.

When to Contact a Medical Professional Return to top

Call your health care provider if you develop reddish bumps on your skin which do not clear with home treatment.

Prevention Return to top

Avoid contact with contaminated water. Wear gloves or wash thoroughly when cleaning aquariums.

Update Date: 4/12/2007

Updated by: Kevin Berman, MD, PhD, Associate, Atlanta Center for Dermatologic Disease, Atlanta, GA. Review provided by VeriMed Healthcare Network.

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