[The value of positive epicutaneous test reactions to 4,4'-diaminodiphenylmethane]

This study was undertaken to determine the significance of positive patch test reactions to 4,4'-diaminodiphenylmethane (DDM). Data of 202 DDM-positive patients concerning age, sex and profession, type, localisation and duration of eczema and combined allergens were evaluated. The results obtained were compared by chi-square-test with those of 3397 consecutive, unselected contact dermatitis patients with negative reactions to DDM. The most conspicuous results were: 1. The positive patch test reaction to DDM is usually a marker for allergy to p-amino-compounds. 2. 39/202 patients showed isolated positive test reactions to DDM. The source of the allergen remained unclear. 3. Workers in chemical laboratories seem to have an increased risk for acquiring DDM-allergy. 4. The clinical relevance of DDM-allergy could only be proven in a few patients.