Comparative study of patch test using traditional method vs. prior skin abrading

Summary Background The patch test is an essential procedure for the investigation of aetiologic diagnosis of allergic contact dermatitis, although it is not yet able to fully reproduce the events of the initial site of contact with the allergen. Objectives The aims of the present study are (i) to assess whether removal of the superficial corneous layer results in test positivity differences vs. the traditional technique, (ii) to assess the probable and/or possible and past and/or present sensitivity and relevance for each method, and (iii) to compare specific relevance of nickel sulphate for each method. Results Concordance of positive reactions was 75.9% (66 of 87), with 21.8% (19 of 87) positivity results on the abraded side only and 2.3% (2 of 87) on the unabraded side (P