Results of standard patch testing in contact dermatitis patients with a short review of other diagnostic aids

ABSTRACT

Standard patch test is one of the reliable tests to identify the allergen in allergic contact dermatitis [ACD]. In the department of Dermatology and Venereology in Rumailah Hospital - Hamad Medical Corporation, Doha - Qatar, 235 patients who were diagnosed to have ACD were patch tested using the European Standard si000 [chemo technique diagnostic with 25 allergens for patch testing - Sweden].86.3% of the patients patch tested were in the age groups from 11-50 years old. The results showed that 85.5% had positive results while 14.5% were negative.The total numbers of positive patch testing readings were 590 varying from one to 12 per patients. The percentages of patients with one, two, three or four positive readings were 23.8%, 20%, 17% and 11.5% respectively. The top ten allergens in this group were;1- Potassium dichromate 18.14%2- Nickel sulfate hexahydrate 13.05%3- Cobalt Chloride hexahydrate 12.03%4- Fragrance mix 7.12%5- 4-phenylene diamine base 5.60%6- formaldehyde 4.58%7- Neomycin sulfate 3.55%8- Colophony 3.55%9- Wool Alcohol 3.4%10- Balsam of Peru 3.4%The result of patch testing was relevant 100% in potassium dichromate, nickel sulfate, cobalt, fragrance mix, paraphenylene diamine and neomycin sulfate