Psychiatric Comorbidities of Childhood-onset Atopic Dermatitis in Relation to Eczema Severity: A Register-based Study among 28,000 Subjects in Finland.

Data on the severity of childhood-onset atopic dermatitis (AD) in relation to psychiatric comorbidities is scarce, even though AD predisposes to psychiatric comorbidities and the commonness of childhood-onset AD and its significance in disease progression are recognized. The purpose of this nationwide, register-based study of child patients diagnosed with AD in Finland between 1987 and 2017 was to determine how psychiatric comorbidities of AD patients differ depending on the disease severity of childhood-onset AD. AD severity was assessed by purchased AD treatment and risk of comorbidities was analyzed by the age of 18 and 30 years. The main finding of our study is that risk of several psychiatric disorders, i.e., depression, anxiety disorders and bipolar disorder, increased by the AD severity in childhood-onset AD already at young age. No difference was found for behavioral disorders, including hyperkinetic disorder, depending on AD severity. Childhood-onset AD is associated with different psychiatric comorbidities depending on AD severity, which supports the importance of mental health evaluation in AD patients.