AN OUTBREAK OF PHYTOPHOTODERMATITIS DUE TO CELERY

Celery is known to contain psoralens, a group of substances that cause a toxic dermal reaction on exposure to ultraviolet A rays (UVA). An o utbreak of phytophotodermatitis amongst 11 workers in a celery harvest in southern Israel is reported. Methods. Analysis of the trigger fact ors was carried out. The patients were questioned regarding their work ing conditions. Samples of the celery that the workers had been harves ting were analyzed for levels of total psoralens by means of high perf ormance liquid chromatography (HPLC). Levels Of UVA were measured. Res ults. It was found that the celery harvested in the south of the count ry contained 84 mug/g fresh weight (f.wt.) total psoralens as compared to 35 mug/g f.wt. in celery harvested in the north of the country at the same time. The following year the celery harvested in the south co ntained only 26 mug/g f.wt. total psoralens. Other risk factors noted were that the subjects had fair skin, wore no protective clothing, and worked with moist hands. In addition, the days were clear and sunny t hus ensuring maximal uv radiation for that time of the year. Conclusio ns. Multiple factors contributed to the outbreak of phytophotodermatit is. A late harvest in the south of the country is incriminated as the cause of the unusually high levels of psoralens in the celery of that year.