Pustular psoriasis and drug-induced pustulosis.

We report the case of a 65-year-old female patient that has suffered several flares of exanthematous pustulosis, some of them attributable to pustular psoriasis and others that were drug-induced, resembling acute generalized exanthematous pustulosis. In particular, we describe two severe flares that were induced by ciprofloxacin. Patch tests yielded positive results to ciprofloxacin and to other quinolones and reproduced the original lesional pattern both clinically and histologically. We discuss the diagnostic challenge that exanthematous pustulosis represents and the value of patch testing in this setting, as a helpful tool to assess drug participation in these eruptions.