Infant palmar hyperlinearity and type 2 inflammatory markers predict atopic dermatitis at 1 year of age.

Background: Identification of clinical signs and biomarkers predicting the onset of paediatric atopic dermatitis (AD) is important for disease prevention strategies. Hyperlinear palms, a minor Hanifin & Rajka criterion, are characterized by an increased number and depth of skin creases and have been associated with both filaggrin gene (FLG) mutations and AD.

Objectives: To investigate whether distinct palmar phenotypes in infancy are associated with AD in early childhood.

Methods: In total, 300 term and 150 preterm newborns were followed clinically for possible AD onset until 2 years. The palm of the hand was photographed at 2 months of age for later blinded clinical assessment. FLG mutations were analysed in buccal cells. Skin tape strips were collected at 2 months of age and analysed for immune and skin barrier biomarkers. Hazard ratios (HR) with 95% confidence intervals (CI) were calculated for the risk of AD development.

Results: Hyperlinear palms at 2 months of age were diagnosed in 14.3% (35/245) of the children. The presence of hyperlinear palms was associated with increased occurrence of AD within 1 year (HR 2.82; 95% CI: [1.59-5.00]; p = 0.0004) and 2 years of age (HR 2.40; 95% CI: [1.39-4.13]; p = 0.002), which remained after adjustment for FLG mutation status within 1 year (aHR: 2.13; 95% CI: [1.08-4.20]; p = 0.03) and within 2 years of age (aHR: 1.79; 95% CI: [0.94-3.38]; p = 0.08). Having both hyperlinear palms and elevated TARC/CCL17 at 2 months of age was further associated with increased AD occurrence within 2 years of age among children born to term (HR 5.66; 95% CI: [1.74-18.41]; p = 0.004).

Conclusion: Hyperlinear palms at 2 months of age are associated with paediatric AD within the first year of life. Our study indicates that the presence of type 2 inflammation at 2 months of age further increases the occurrence of AD.