Swimming pool granuloma
A swimming pool granuloma is a long-term (chronic) skin infection caused by the bacteria Mycobacterium marinum.
Aquarium granuloma; Fish tank granuloma
Causes, incidence, and risk factors
A swimming pool granuloma occurs when water containing Mycobacterium marinum bacteria enters a break in the skin. A skin infection occurs about 3 weeks later.
Risks include exposure to swimming pools, salt water aquariums, or ocean fish.
The elbows, fingers, and back of the hands are the most common body parts affected. The knees and legs are less commonly affected.
The nodules may break down and leave an open sore. Or they may spread up the limb.
Signs and tests
Tests to diagnose swimming pool granuloma include:
Antibiotics are used to treat this infection. They are chosen based on the results of the culture and skin biopsy.
You may need several months of treatment with a combination of antibiotics. Surgery may also be needed.
Swimming pool granulomas can usually be treated completely with antibiotics.
Occasionally, joint or bone infections occur. The disease may be longer or more complicated in patients whose immune system is not working properly.
Calling your health care provider
Call your health care provider if you develop reddish bumps on your skin which do not clear with home treatment.
Avoid contact with contaminated water. Wear gloves or wash thoroughly when cleaning aquariums.
Holland S. The nontuberculous mycobacteria. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 346.
Reviewed By: David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine; and Jatin M. Vyas, MD, PhD, Assistant Professor in Medicine, Harvard Medical School, Assistant in Medicine, Division of Infectious Disease, Department of Medicine, Massachusetts General Hospital. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.