Contact allergy in atopic dermatitis: A prospective study on prevalence, incriminated allergens and clinical insights.

Background: The relationship between atopic dermatitis (AD) and allergic contact dermatitis (ACD) is a matter of debate.

Objectives: The purpose of our study is to assess the frequency of ACD in patients with AD, the incriminated allergens and the potential risk factors.

Methods: This is a prospective study, including cases of AD diagnosed based on Hanifin and Rajka's criteria. All patients were patch tested to the European baseline series and corticosteroid series.

Results: Ninety-three patients were included. Fifty-six patients (60.2%) had positive patch test results of which 71.4% were relevant. The most frequent allergens were: textile dye mix (24.7%), nickel (20.4%), cobalt (12.9%), isothiazolinone (8.6%), quanterium 15 (4.3%) and balsam of Peru (4.3%). Chromium, fragrance mix I, fragrance mix II and PTBP were positive in three cases (3.2%). Two cases of allergy to corticoids were identified. Facial involvement and duration of AD were significantly associated with contact sensitization (p = 0.04 and p = 0.005, respectively). Avoidance of relevant allergens resulted in a statistically significant decrease in SCORAD (p < 0.001).

Conclusions: ACD remains an important co-morbidity of AD. We observed a high frequency of ACD to textile dyes, isothiazolinones and fragrances. Avoidance of relevant allergens has resulted in an improvement of patients' skin symptoms.