Risk factors for common contact allergens and patch test results using a modified European baseline series in patients tested during between 2000 and 2009 at Siriraj Hospital.

BACKGROUND Surveillance of contact allergy using patch testing has demonstrated its value in detecting time trends. This study demonstrates the results of patch testing performed between 2000 and 2009 at the contact dermatitis clinic, Siriraj Hospital, Bangkok and risk factors for the top 5 common allergens. METHODS A retrospective review of medical records was conducted from January 2000 to December 2009. All Patients who were patch tested using a modified European baseline series were studied. RESULTS There were 852 cases (206 males and 646 females; mean age 39.14 years). The top 5 most frequent allergens were gold sodium thiosulfate (30.7%), nickel sulfate (27.6%), potassium dichromate (20.8%), fragrance mix (18.3%) and cobalt chloride (16.0%), respectively. There was no statistically significant difference in the trends of positive patch test reactions for individual allergens during the 2000s. Gold sensitivity was found more common in females and in the head and neck regions. Nickel sensitivity was more common in females. Chromate sensitivity was more common in males and subjects aged = 40 years. Fragrance sensitivity was more common in females and subjects aged = 40 years. Among the patients with metal (chromate, nickel, cobalt and gold) allergy, the patient's recollection of a history of an allergic reaction to metal was significantly associated with a positive patch test reaction to either one of these metals, (P < 0.001; OR, 2.56; 95%CI, 1.87-3.50). CONCLUSIONS The prevalence of contact sensitization appears to have not changed much during the decade. Further study, involving patients from all institutions in Bangkok, would provide a more comprehensive view of contact allergens in the region and lead to the creation of a local standard series.