Factors associated with severity of atopic dermatitis – a Finnish cross‐sectional study

Background Severity‐associated factors in atopic dermatitis (AD) have focussed on early onset, concomitant atopic diseases, markers of Th2‐shifted inflammation and filaggrin mutations. Objectives To investigate factors associated with severe AD in Finnish patients. Methods We conducted a single‐centre, cross‐sectional observational study with 502 AD patients aged 4.79 to 79.90 years (mean 32.08 years). Disease severity was assessed with the Rajka–Langeland severity score and EASI and associated clinical signs were evaluated. Data regarding onset, relatives, atopic and other comorbidities was gathered retrospectively. We investigated total serum IgE‐levels, a panel of filaggrin null mutations and functional variants of genes associated with skin barrier defects. Results Factors more frequent in severe AD included early onset (P = 0.004, 95%CI 0.000–0.024), male sex (P = 0.002, 95%CI 0.000–0.11), history of smoking (P = 0.012, 95%CI 0.000–0.024), concomitant asthma (P = 0.001, 95%CI 0.000–0.011), palmar hyperlinearity (P = 0.013, 95%CI 0.014–0.059), hand dermatitis (P = 0.020, 95%CI 0.000–0.029) and history of contact allergy (P = 0.042, 95%CI 0.037–0.096). Body mass indices (P