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

Abstract

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 < 0.000, 95%CI 0.000-0.011) and total serum IgE-levels (P < 0.000, 95%CI 0.000-0.011) were higher in severe AD. No differences were observed for allergic rhinitis, allergic conjunctivitis, food allergy, peanut allergy, prick positivity, keratosis pilaris, history of herpes simplex infections, filaggrin null mutations and other gene variants.

Conclusions: Severity determinants in Finnish patients seem to be early-onset, male sex, smoking, overweight, concomitant asthma, palmar hyperlinearity, hand dermatitis and high IgE-levels. A sub-typing of patients in relation to confirmed severity determinants may be useful for course prediction, prognosis and targeted AD management.

Figure 1

Clinical signs and patient history data; (a) Proportion (%) of patients regarding sex (males), smoking (history of smoking >5 years), disease onset >2 years, atopic dermatitis in first‐degree relatives (FDR), prick positivity to aeroallergens, allergic rhinitis (AR), allergic conjunctivitis (AC), food allergy and asthma; (b) Mean absolute values of disease severity (Rajka and Langeland severity score, RLS), EASI, age and body mass index (BMI); (c) Proportion (%) of patients with different associated clinical signs, HSV: Herpes simplex virus. [Colour figure can be viewed at wileyonlinelibrary.com]

Figure 2

Total serum IgE‐levels and filaggrin null‐mutation status; (a) Comparison of serum total IgE‐levels (kU/L) at the clinical visit; 2 highest outliers are not shown in the graph (patients with severe AD, 189 500 and 157 240 kU/L); lower and upper hinge of the box: 1st and 3rd quartile; whiskers: 1.5 * IQR; line: median, cross: mean; dots: outliners; (b) Highest total serum IgE‐levels (kU/L) of the preceding 10 years; whiskers: 1.5 * IQR; line: median, cross: mean; dots: outliners; (c) Proportion (%) of patients with carrier status regarding indicated filaggrin null mutations and combined heterozygosity. [Colour figure can be viewed at wileyonlinelibrary.com]