Which children should we patch test?

Abstract

Allergic contact dermatitis (ACD) in childhood was considered rare until recently. However, reports are increasing, which may reflect an increased incidence and/or more frequent patch testing of children. It is also likely that allergen exposure in children has changed with time. To determine the most common contact allergens and the rate of positive patch-test reactions among children with suspected contact allergy. We carried out a retrospective case study of 114 children (66 girls and 48 boys) aged from 3 to 15 years (median 11.5) patch tested over a 3-year period. Indications for patch testing included uncontrolled or deteriorating atopic dermatitis, localized dermatitis or a history of reacting to a specific allergen. Of 110 children for whom we had notes, 83 (75%) had a history of atopy. Positive reactions that were of current, past or possible relevance were seen in 61 children (54%); in 58 (52%) of 111 tested with the standard series (SS) and in 6 (10%) of 60 tested with the medicament series. None of the children patch tested to the corticosteroid (n = 47), shoe (n = 15), fragrance (n = 12), cosmetic (n = 10) or rubber (n = 5) series had a positive reaction. However, 11 (10%) reacted to rubber allergens within the SS and one of five to their own shoes. The lowest rate of relevant positive reactions was among those with deteriorating atopic dermatitis (22%) and facial (33%) or perioral dermatitis (40%), and the highest rate amongst those with eyelid (86%) or hand (71%) dermatitis. Nickel was the most common allergen (20%) in line with previous reports (82% female), followed by rubber chemicals (10%), fragrance (7.2%), cobalt (5.4%) and lanolin (wool alcohol) (4.5%). The reported incidence of ACD among children, in particular nickel and rubber allergy, appears to be increasing, which may relate to changing fashions and hobbies. Contact allergy should be considered in all children with dermatitis, particularly with eyelid or hand dermatitis, and patch testing carried out more frequently.