ABSTRACT
Three cases of swimming pool granuloma are reported.Case 1:a 40-year-old female presented with a 2-month history of nodules and plaques on the right hand and forearm.She was a tropical fish salesperson but denied trauma history.Skin examination revealed multiple irregularly sized,dark-red nodules and plaques on the joints of right fingers,wrist,and elbow,as well as multiple subcutaneous nodules simulating strings of beads on the right upper limb.Case 2:a 48-year-old female presented with a 2-month history of nodules and plaques on the left hand and forearm.There was a history of trauma due to tropical fish tank and filter cleaning.Physical examination showed multiple deep purple plaques and painless subcutaneous nodules scattered on the left hand,wrist,and upper limb.Case 3:a 39-year-old male presented with a 3-month history of nodules on the fingers of both hands.There was no history of trauma,but he was a tropical aquarist.Skin examination revealed multiple soybean-sized dark-red nodules on the extensor aspect of interphalangeal joints of both hands.Fungal examinations yielded negative results in the 3 cases,while histopathology revealed infectious granuloma with a mixed inflammatory cell infiltrate.All of the cases showed positive results in purified protein derivative (PPD)skin test.Mycobacterium marinum was isolated from the lesional tissue of Case 1 and 2,but not from Case 3.All the patients were diagnosed with swimming pool granuloma,and given anti-atypical mycobacterial therapy including oral rifampin and clarithromycin.The lesions disappeared after 1 to 3 months of treatment,with the treatment course varying from 2 to 5 months.No recurrence was observed during a 3- to 12-month follow-up.