Patch testing with different allergen series: Retrospective study from Selayang Hospital,Malaysia

ABSTRACT

Background: Majority of the hospitals in Malaysia have limited allergen series for patch testing. Since January 2011, Department of Dermatology in Selayang Hospital has extended its number of allergen series available for testing. Objectives: The aim of this study was to evaluate whether other series besides the European baseline series (EBS) deserve to be tested on suspected patient with contact dermatitis. Methods: Patch test results of patients visiting Dermatology clinic in Selayang Hospital from January 2001 to June 2011 were reviewed retrospectively. Results: Out of 129 patients who were patch tested, 98 (76%) patients had positive patch test, 30 (23.3%) patients had negative patch test and 1 (0.7%) patient had ‘Angry back’ reaction. The most commonly positive allergens were Nickel sulfate 45 (34.9%), Cobalt chloride 21 (16.3%), Potassium dichromate 15 (11.6%) and Balsam Peru 15 (11.6%). None of the patient had positive patch test to Mercaptobenzothiazole, Sesquiterpene lactone mix, Fragrance mix II and Lyral in the (EBS). The number of patient that will be missed if certain series are not tested were Textile Colours & Finish (TF) (n=4/7, 57.1%), Plastic & Glues (PG) (n=4/19, 21.1%), Hairdressing (n=1/5, 20%), Cosmetic (n=2/12, 16.7%), Rubber Additives (n=12/77, 15.6%), Medicament (n=1/9, 11.1%), Plant (n=0/5, 0%), Cutaneous Adverse Drug Reaction (n=0/3, 0%) and Leg Ulcer (n=0/1, 0%). Conclusion: The absence of positive patch test to Mercaptobenzothiazole, Sesquiterpene lactone mix, Fragrance mix II and Lyral does not support inclusion in the EBS in our region. Additional series especially TF and PG are important series to be tested in suspected patient.