MedlinePlus Medical Encyclopedia: Swimming pool granuloma

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Swimming pool granuloma

Contents of this page:
Alternative names Definition Causes, incidence, and risk factors Symptoms Signs and tests	Treatment Expectations (prognosis) Complications Calling your health care provider Prevention

Alternative names

Aquarium granuloma

Definition Return to top

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

Causes, incidence, and risk factors 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. The lesions appear as reddish bumps (papules) that slowly enlarge 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.

Symptoms Return to top

history of exposure to swimming pools, salt water aquarium or ocean fish
single or multiple red to reddish-purple bumps
occur frequently on the hands, elbows, knees, legs, and areas of trauma
may be present for months

Signs and tests Return to top

Though swimming pool granulomas have a characteristic appearance, a skin biopsy and culture is usually necessary to confirm the diagnosis. A PPD tuberculin skin test will usually be positive as well.

Treatment Return to top

Oral antibiotics are needed to clear this infection. Choices include minocycline, Bactrim, clarithromycin, and levofloxacin. Several months of treatment are often required.

Expectations (prognosis) Return to top

Swimming pool granulomas can usually be treated completely with antibiotics.

Complications Return to top

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

Calling your health care provider 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 was thoroughly when cleaning aquariums.

Update Date: 8/15/2003

Updated by: Michael Lehrer, M.D., Department of Dermatology, University of Pennsylvania Medical Center, Philadelphia, PA. Review provided by VeriMed Healthcare Network.

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