Patch Test Results In370Patients With Suspected Allergic Contact Dermatitis In Central China

Objective: To identify the common allergens of allergic contact dermatitis in central Chinaand investigate the association between those allergens and patients‘gender, age,occupation, affected parts, in order to provide the basis of prevention of allergic contactdermatitis and choice of patch tests.Methods: A analysis on370outpatients with suspected allergic contact dermatitis fromAllergy department of TongJI Hospital, Tongji medical college，Huazhong university ofscience&technology between Jan2010to Dec2012. All the patients were patch testedusing selected allergens with the European baseline series–―Ruimin‖, which is provided byBeijing yuan kang medical technology Co. LTD.The results were divided into negative, suspicious, weak positive, strong positive andextremely strong positive. All cases were divided into groups according to gender, age,occupation and affected parts. Positive rate of the allergens should be counted on differentgroups. The data were coded and analyzed using the Statistical Package for Social Sciences(SPSS17.0). Pearson chi-squared test and Fisher exact test were used to evaluate thestatistical significance of different variables, and a P value of0.05was taken as the cut-offpoint for the level of significance.Results: Of the370patients with suspected allergic contact dermatitis in this study, thewhole positive rate of the contact allergens was76.76%. The five most common contactallergens were nickel sulfate (34.32%), flagrance mix (18.65%), cobalt chloride (18.38%),potassium dichromate (17.3%) and formaldehyde (12.7%). Acording to gender, positivereaction to carba mix was more common among men than among women, and thedifference was statistically significant (P<0.05), positive reaction to nickel sulfate andformaldehyde was found to be more common among women, this difference wasstatistically significant (P<0.05). Acording to age, positive reactions to nickel sulfate weremore frequent in the younger group (=<40years) and to N-cyclohexyl-ylthiopathalocyanine, formaldehyde, flagrance mix and carba mix were more frequent in theolder group (>40years). According to occupation, nickel sulfate was the main allergen ofoffice workers, teachers/students and housewifes, p-phenylenediamine was the mainallergen of hairdressers, benzene mix was the main allergen of medical staffs, potassium dichromate was the main allergen of construction workers. Acording to affected part,positive reaction to thiuram mix were more common on the hand and flagrance mix weremore common on the face.Conclusions: Patch test is an important method to diagnose allergic contact dermatitis.Nickel sulfate, flagrance mix, cobalt chloride, potassium dichromate a nd formaldehyde arethe main allergens causing allergic contact dermatitis in Centre China. With the significantdifference of patients‘gender, age, occupation and affected parted, the patch test results willbe different. Although carrying out inclusion and exclusion criteria strictly, we still getnegative rate of23.24%, indicating that original series can‘t cover all the sensitizer causingallergic contact dermatitis, so it is necessary to make proper adjustments of the existingbaseline series.