Higher Prevalence of Contact Sensitization to Dodecyl Gallate in Patients With Atopic Dermatitis: A Cross-Sectional Study.

Background

Gallates are antioxidant preservatives widely used in cosmetics and foods, with dodecyl gallate considered the most allergenic derivative. Despite increasing exposure, it is not included in European baseline patch-test series, and its relevance in patients with atopic dermatitis (AD) remains poorly defined.

Objectives

To determine the prevalence of contact sensitization to dodecyl gallate in patients with AD compared with nonatopic controls and to explore age- and severity-related differences.

Methods

In this cross-sectional study, 160 consecutively tested patients were included: 80 with AD (Hanifin-Rajka criteria) and 80 nonatopic controls with allergic contact dermatitis. Patch testing followed International Contact Dermatitis Research Group guidelines. All patients were tested with the Polish Baseline Series, and dodecyl gallate 0.25% petrolatum was added as a single supplemental allergen. Reactions were read at 48 hours, 72 hours, and Day 7; + to +++ reactions at 72 hours were considered positive.

Results

Sensitization to dodecyl gallate occurred in 16/80 patients with AD (20.0%) and 6/80 controls (7.5%) (odds ratio 3.08; 95% Confidence Interval (CI) 1.15-8.57; P = 0.037). Within the AD cohort, sensitization was detected in 10/36 adults (23.3%) and 6/44 children (13.6%), whereas among controls it was observed in 6/38 adults (15.8%) and 0/42 children. The difference was significant in children (13.6% vs 0%; P = 0.026) but not in adults (23.3% vs 15.8%; P = 0.264). No association was found between AD severity and sensitization (P = 0.720). Most reactions were weakly positive; 3 ++ reactions occurred only in AD.

Conclusions

Dodecyl gallate is a clinically relevant and likely underrecognized allergen, with a significantly higher prevalence of sensitization in patients with AD-driven primarily by the pediatric population. These findings support consideration of targeted testing for dodecyl gallate, particularly in children with AD and persistent eczematous dermatitis.