Intracutaneous testing for the diagnosis of delayed-type hypersensitivity to nickel, cobalt and chromium.

Abstract

106 patients with type TV allergy to nickel, 32 sensitized to cobalt and 44 to chromium previously confirmed by patch testing (FCS/ICDRG-criteria, 24-h-exposition), were tested intracutaneously with 0,1 mi of 1 mmol aqueous solutions of nickel sulfate, cobalt chloride and potassium dichromate. A second group of 106 nickel-sensitized patients and 14 chromium-allergic persons received 0,1 ml of a 10 mmol solution of above mentioned metal salts. Readings were done 20 minutes, 6 h, 24 h, 48 h after injection (and after 72 h in 36 patients). Persisting infiltrate after 24 h was judged as delayed-type hypersensitivity. In the first subgroup no eczematous reactions could be reproduced in nickel-allergic patients, 3 of 32 persons with hypersensitivity to cobalt and 4 of 44 individuals with chromium allergy showed delayed-type reactions. In the second group (testing with 10 mmol solutions of metal salts) 3 of 106 patients with nickel allergy and 6 of 14 persons with chromate hypersensitivity showed true eczematous reactions (the intracutaneous testing of aqueous cobalt solution wasn't tolerated at this concentration). The results oft this study demonstrate the necessity of critical appraisal on former studies.