Changing patterns of contact sensitivity in Sofia.

1237 patients with contact sensitization were patch tested five times with the standard patch test series at 3-year intervals. The study was carried out during the period 1975-1987. The results point out the increasing significance of the most common allergens in the industrially developed countries: potassium dichromate, isopropylaminodiphenylamine, formalin, p-phenylenediamine and nickel sulfate.