Atopy and Sensitization to Allergens Known to Cause Systemic Contact Dermatitis

Background: Atopic dermatitis (AD) associated with respiratory atopy may represent a form of systemic contact dermatitis (SCD), whereby AD flares after ingestion or inhalation of allergens. Objective: The aim of the study was to compare the prevalence of positive patch tests to allergens known to cause SCD in AD patients with and without respiratory atopy. Methods: This is a retrospective study of patients with AD patch tested to 23 allergens known to cause SCD. Positive patch tests were compared between AD patients with and without respiratory atopy, stratified by age and wet or dry work occupation. Conclusions: Children and adolescents, but not adults, with AD and respiratory atopy were more likely than age-matched AD patients without respiratory atopy to have positive patch tests to these allergens (odds ratio, 2.33; 95% confidence interval, 1.13-4.79). Moreover, AD patients with respiratory atopy and engaging in wet work, but not dry work, occupations were more likely than AD patients without respiratory atopy to have positive patch tests to allergens known to cause SCD (odds ratio, 1.47; 95% confidence interval, 1.05-2.06). Thus, respiratory atopy and wet work are associated with sensitization to allergens known to cause SCD in patients with AD, and patch testing may be valuable in identifying systemic triggers of dermatitis in these patients.