Allergic contact dermatitis to plants in a Spanish dermatology department: a 7-year review.

To investigate the incidence of allergic contact dermatitis (ACD) to plants in our area, we reviewed the records of the patients that were studied in the Allergic Contact Unity of our hospital in the last 7 years (2248 patients). We found 69 cases of positive patch tests to plant allergens, representing 3% of all the patients in that period. Diallyl disulfide was the most frequent allergen (47 cases), involving mainly middle-aged housewives with chronic hand eczema. Positive tests to sesquiterpene lactone mix (SL mix) were found in 11 patients, mostly middle-aged rural workmen with an airborne clinical pattern. Other allergens detected were lichens, primin, tulipalin A and wood. These results show a high incidence of ACD to diallyl disulfide that, in our opinion, should be tested in all housewives or cooks with chronic hand eczema. The predominance of the classical airborne pattern of allergy to SL in our study may be because the airborne way of allergen exposure in our area, with a high percentage of rural population, is the most frequent, and it makes it important to remember this possibility in the differential diagnosis of photosensitivity.