A case of opportunistic skin infection with Mycobacterium marinum during adalimumab treatment in a patient with Crohn's disease.

Opportunistic infections, especially reactivation with M. tuberculosis, are major complications during treatment with anti-TNF agents. Infections with atypical mycobacteria like Mycobacterium marinum are rare and tend to turn into a difficult and prolonged course due to delayed diagnosis. This is the first case of M. marinum infection during adalimumab therapy in a patient with Crohn's disease. The most important diagnostic step was a detailed medical history as PCR tested for M. tuberculosis and for atypical subspecies was false negative. Up to now a discontinuation of anti-TNF therapy has been recommended, however, there is no consensus about the reintroduction of biologicals after sufficient anti-infective therapy. In this patient anti-TNF therapy had to be reintroduced because of increasing activity with no relapse of M. marinum after a follow-up of 12 months.