Repeated hand urticaria due to contact with fishfood

Background The etiology of urticaria is often difficult to determine. Howev er, in case of repeated circumsance-connected urticaria, the reason may be easily clarifyable. Case A 51-year-old healthy woman repeatedly experienced occupational hand u rticaria when handling fish food. An unexpected reason for the urticaria wa s found in that the fishfood contained histamine as a "contaminant". Conclusions In fishfood batches, biological degradation can produce histami ne and possibly other toxic substances that can lead to occupational health problems.