Patch test results in 542 patients with suspected contact dermatitis in Turkey

In this retrospective study, patch test results of 542 patients (303 female and 239 male), referred to our clinic between June 1996 and July 1999, were evaluated. All patients were patch tested with 32 allergens of an extended European standard series, 140 patients were tested with supplemental series, and 246 patients with their own substances. 280 (51.7%) patients had 1 or more positive results but allergic contact dermatitis, according to clinical relevance, was diagnosed in only 190 (67.9%) of these. Nickel sulfate was the most frequent sensitizer (19.1%), followed by potassium dichromate (11.8%), palladium chloride (9.4%), cobalt chloride (8.5%), and thiuram mix (7.7%). Frequencies of contact allergy to fragrance mix (5.5%), balsam of Peru (Myroxylon Pereirae resin) (2%), quaternium-15 (0.6%), and Kathon CG (methylchloroisothiazolinone+methylisothiazolinone) (0.2%) were relatively low, while no positive reactions were obtained to paraben mix in any case. Current clinical relevance to the present dermatitis was most frequently seen with carba mix (96.2%), thiuram mix (95.2%) and potassium dichromate (78.1%), whereas this rate was low for nickel (37.5%). In 85.8% of patients with allergic contact dermatitis, the responsible allergen was detected by testing with the extended standard series alone (18.4% identified by testing with the additional 10 allergens), in 11.6% by testing with the patients' own substances, and in 2.6% by testing with the supplemental series. Occupational contact dermatitis was diagnosed in 77 of the patients with positive reactions (27.5%), most of these being construction workers and house painters who showed relevant sensitizations to potassium dichromate, cobalt chloride, thiuram mix and carba mix. There was no statistically significant difference in the total contact sensitization rate between atopics and non-atopics, but contact sensitivity to nickel sulfate and palladium chloride was significantly higher among atopics. MOAHL index in % was: 44.1/14.2/24.9/ 54.4/2.4. In conclusion, we believe that similar large series of patients would be helpful to delineate the exact profile of contact dermatitis in Turkey.