Increased attention-deficit/hyperactivity symptoms in atopic dermatitis are associated with history of antihistamine use.

BACKGROUND

Epidemiologic evidence indicates a relevant association between atopic dermatitis (AD) and attention-deficit/hyperactivity disorder (ADHD). Underlying mechanisms and ways to best identify subgroups of AD patients at risk for ADHD are poorly understood.

AIMS OF THE STUDY

To compare sociodemographic, clinical and psychosocial characteristics of children with AD, ADHD, comorbid AD/ADHD and age-matched healthy controls and to investigate aspects of AD related to ADHD symptoms.

METHODS

Applying a factorial design, we investigated 4 groups of children aged 6-12 years: AD-only (ie, without ADHD), ADHD-only (ie, without AD), AD + ADHD and healthy controls (HC; ie, no AD/no ADHD). Using validated instruments, ADHD symptoms and other behavioural problems, quality of life, parenting stress and sleeping problems were compared between groups. In children with AD-only, clinical signs (objective SCORAD), symptoms (POEM, VAS pruritus, VAS sleeping problems) and previous treatment of AD were assessed to investigate disease patterns related to ADHD symptoms.

RESULTS

Compared to HC (n = 47), children with AD-only (n = 42), ADHD-only (n = 34) and comorbid AD + ADHD (n = 31) had significantly increased behavioural problems and decreased quality of life. Children with AD-only had significantly higher levels of ADHD symptoms than HC. In children with AD-only, previous use of antihistamines was significantly associated with increased ADHD symptoms (OR 1.88; 95% CI 1.04-3.39). Current clinical signs and AD symptoms were unrelated to the level of ADHD symptoms.

CONCLUSIONS

Even if the clinical diagnosis of ADHD is excluded, children with AD show increased levels of ADHD symptoms. Further investigations need to determine whether early antihistamine exposure is a major risk factor for ADHD or a surrogate for previous AD severity and/or associated sleeping problems.