Trauma-localized fixed drug eruption: involvement of burn scars, insect bites and venipuncture sites.

Little is known about why fixed drug eruption (FDE) lesions initially appear in a particular area of predilection. We describe 2 cases in whom the FDE lesions initially appeared exactly at the same sites of a previous trauma, such as burn scars and insect bites, and at a venipuncture site. The interval between the original trauma and the initial onset of FDE ranged from 2 days to 22 years. These 'trauma-localized' FDE lesions are helpful for our understanding of the mechanisms of FDE and other skin diseases, which often appear in their particular areas of predilection, a finding known as 'recall phenomenon'.