Skin patch testing as a diagnostic tool for allergic contact dermatitis to metals

Aliakhnovich N.S.

Vitebsk State Medical University, Vitebsk, Belarus

A method for conducting skin patch allergy testing with metal compounds was developed and tested.

A total of 38 patients have been examined – 22 with a confirmed diagnosis of allergic contact dermatitis and 16 healthy volunteers.

All patients completed the developed questionnaire for metal hypersensitivity identification and underwent patch testing with metal compounds and petroleum jelly using standard dilutions: 1% chromium (III) chloride, 1% cobalt (II) chloride, 0.5% ammonium molybdate (VI), 10% aluminum (III) hydroxide, 2.5% nickel (II) sulfate, and 0.1% titanium (IV) oxide. 266 applications were conducted: 228 with metal compounds and 38 controls. Additionally, 8 patients with a high probability of hypersensitivity to titanium compounds underwent a provocative mucosal test – a sublingual-oral test with titanium oxide.

A questionnaire score of more than 2.5 points, with 100% sensitivity and 93.7% specificity, was found to enable the selection of patients for further provocative testing with metal compounds (ROC analysis: AUC=0.991, p<0.001).

The use of patch testing accompanied by anamnestic data to diagnose allergic contact dermatitis to metals provides a diagnostic accuracy of 84% (sensitivity 73%, specificity 100%).

It was found that in the majority of cases (94%), allergic contact dermatitis to metals is caused by sensitization to nickel, followed by chromium and cobalt (38% and 25%), followed by sensitization to titanium (19%), and molybdenum and aluminum (13%).

If there is a high probability of hypersensitivity to titanium based on the anamnesis data, it is necessary to conduct a sublingual-oral test with titanium oxide in addition to the application test with titanium oxide due to its higher sensitivity in titanium compound sensitization detection.