Key Message
The study has revealed notable associations between food sensitisations and the disease severity as well as epidermal barrier impairment in children with atopic dermatitis (AD). Specifically, the findings indicate that children with AD who were sensitised to higher numbers of food allergens had higher SCORAD scores and greater epidermal barrier impairment. In addition, SCORAD score and SCH levels at lesional skin could be predictive factors for food sensitisation in children with AD. The findings of this study suggest that clinicians should consider screening for food sensitization in children with moderate-severe AD and/or low SCH levels at lesional skins.
INTRODUCTION
Atopic dermatitis (AD), characterised by itchy eczema skin lesions, is one of the most common allergic diseases in children with the aged less than 5 years.1 T helper 2 (Th2) response is an important pathological mechanism of AD, which leads to sensitisation to FAs and aeroallergens.2,3 Previous studies from Europe and America showed that 91% of children with AD were sensitised to at least one FA.4 Nevertheless, the profile of sensitised FAs among children with AD in Europe and America could differ from the profile among children in Southeast Asia.
Stratum corneum hydration (SCH) and transepidermal water loss (TEWL) are two important measures of the epidermal integrity.5Decreased SCH and increased TEWL indicate an impaired epidermal barrier, which facilitates the penetration of FAs into the skin, where they are captured and presented by antigen-presenting cells, leading to food sensitisation (FS).3,5,6 The Scoring Atopic Dermatitis (SCORAD) score is a useful tool for assessment of AD severity; SCORAD results are positively associated with allergen sensitisation.7 In this study, we hypothesised that sensitisation to FAs was associated with AD severity and epidermal layer impairment in children with AD. Accordingly, we evaluated the associations of FS with TEWL, SCH, and SCORAD scores. We then explored factors that could predict FS in children with AD.
MATERIALS AND METHODS
Patients
In this cross-sectional study, we recruited 100 children (age 12-60 months) diagnosed with AD at the Allergy and Clinical Immunology Unit of the University Medical Center at Ho Chi Minh City, Vietnam. We excluded patients with the following comorbidities: itchy vulgaris, scabies, seborrheic dermatitis, contact dermatitis, T-cell lymphoma, psoriasis, photosensitive dermatitis, and erythroderma. Study subjects were asked to stop using moisturizers at least 3 hrs prior to enrolment.
The guardians of all study participants provided written informed consent for enrolment. This study was approved by the Institutional Review Board Ethics Committee of the University of Medicine and Pharmacy at Ho Chi Minh City (IRB No: 633/ĐHYD-HĐĐĐ).
Measurement of TEWL and SCH levels
We measured TEWL and SCH using the GPSkin Barrier Pro® device (Gpower Inc., South Korea), in accordance with the manufacturer’s instructions. TEWL and SCH levels were measured in triplicate at the volar forearm area; mean levels were used for statistical analysis. The lesional skin regions selected for measurement of TEWL and SCH were prioritised in the following order: forearms, arms, legs, and thighs.
Measurement of serum IgE antibodies to FAs
Serum IgE antibodies against 31 FAs were measured by immunoblotting using the EUROLINE Atopy “Venezuela” kit (EUROIMMUN, Lubeck, Germany, kit ID lot A220722AM) in accordance with the manufacturer’s instructions. A participant was assumed to have a FS if they had a positive serum IgE antibody result (> 0.35 IU/mL) to at least one tested FA.
Statistical analysis
Independent samples t -tests were used to compare mean levels among study groups. Receiver operating characteristic (ROC) curves were established to determine cut-off points for TEWL level, SCH level, and SCORAD score in terms of predicting FS. Stata 14.0 (StataCorp) was used for statistical analysis. p < 0.05 was considered statistically significant.
RESULTS