After being stung by shrimp, one is prone to contracting swimming pool granuloma or dermatophytosis-like infection. Swimming pool granuloma is a limited lesion caused by Mycobacterium marinum infection, which usually occurs at the site of trauma and has an incubation period of about three weeks, and presents as a single reddish-brown papule, nodule or plaque that can break down to form a small superficial ulcer. It usually has no conscious symptoms and can persist for years or resolve on its own within a few months. In contrast, the infection is caused by the bacterium Clostridium perfringens, and is characterized by well-defined, edematous erythema, sometimes accompanied by blisters, and mild itching and pain. It is self-limiting and usually clears up on its own in about three weeks.