Epicutaneous patch test results in children and adults with allergic contact dermatitis in Karlovac county: a retrospective survey.

The aim of the study was to evaluate the results of epicutaneous patch testing with a standard series of contact allergens in children suspected to have allergic contact dermatitis (ACD), and to compare the results of patch testing between children and adults. Clinical records of children defined as patients aged ≤18 years and adults examined at Department of Dermatology and Venereology, Karlovac General Hospital, for suspicion of ACD during the 1994-2009 period were reviewed. Epicutaneous patch testing with a standard series of contact allergens, manufactured by the Institute of Immunology, Zagreb, Croatia, was performed in group 1 consisting of 412 children (274 female and 138 male, mean age 13.4 years, range 4-18 years) and group 2 consisting of 4440 adult patients (2918 female and 1522 male, mean age 40.3 years, range 19-81 years). The most common six allergens differed between the two groups. Adult subjects were divided into three age subgroups: 19-40 (n=1708), 41-60 (n=1570) and 61-81 (n=1162 subjects). The high sensitization rate in younger subgroup and lower sensitization rate in the oldest group compared to adult patient group as a whole was statistically significant (P<0.05). In children, the most common positive reactions were recorded to nickel sulfate (25.4%), thimerosal (17.8%), cobalt chloride (11.6%), fragrance mix (8.9%), white mercury precipitate (6.2%), formaldehyde (4.7%) and other allergens (25.4%). In adult patients, positive reactions were most common to nickel sulfate (32.6%), cobalt chloride (10.8%), fragrance mix (9.0%), wood tars (7.1%), potassium dichromate (6.6%), balsam of Peru (5.1%) and other allergens (28.8%). The group of children included 179 (43.4%) atopic subjects (according to Hanifin and Rajka criteria) and 233 (56.6%) non-atopic subjects. There was no statistically significant between-group difference and no statistically significant difference in nickel sulfate, cobalt chloride, fragrance mix and balsam of Peru sensitization between children and adult patients. A higher sensitization rate in children versus adults was recorded for thimerosal, white mercury precipitate and formaldehyde. Less frequent sensitization in children versus adults was found for wood tars and potassium dichromate. It is concluded that pediatric ACD exists and is more common than previously recognized. Sensitization to allergens differs between children and adults.