339 Sensitization to Contactants in Patients with Atopic Dermatitis

BACKGROUND: Atopic dermatitis (AD) is a chronic inflammatory pruritic skin disease with extensive interindividual variation and multiple internal and external factors. In this study, we evaluated whether the atopic dermatitis severity (SCORAD index), gender, age, age onset or the presence of Allergic rhinitis (AR), Allergic conjunctivitis (AC) or Asthma has an influence on contact sensitization to common contactant allergens. METHODS: 30 AD patients were evaluated in the Division of Allergy of Federal University of São Paulo. AD was diagnosed according to the Hanifin and Rajka's criteria and all patients were currently under regular treatment. Questionnaire (age, gender, age at onset, presence of AR, Asthma or AC), clinical examination and skin patch tests were carried out on all patients at the beginning of the study. Patients in regular use of oral CE; topical CE and/or calcineurin inihibitor use or having active AD lesions in the back were excluded from the study. Patch test was applied onto the upper back with 8 mm chambers attached with hypoallergenic tape and removed after 48 hours. The interpretation of the test reactions was performed at 48th and 96th hour. RESULTS: Positive Patch-test reaction occurred in 14/30 (46.6%). Among those with positive patch-test, Nickel was responsible for 42.8% and Thimerosal for 28.5%. All patients finished the study and no adverse reactions occurred. Positive and negative Patch-test groups found no statistically significant difference (P > 0.05) when comparing: SCORAD index, sex, age, age of onset and presence of AC, AR or asthma. CONCLUSIONS: According to our results, sensitization to common contact allergens in AD patients was more frequent than in normal subjects. Although we did not found an explanation to these findings, indiscriminate exposure to topic products should be avoided so that new sensitization or risk of deteriorating AD occurs. The benefits of avoidance to the contactants considered positive should be evaluated in the follow-up of these patients.