Specific IgG and IgA of common foods in Chinese children with eczema: Friend or foe

Abstract

Background: Specific immunoglobulins G and A (IgG and IgA) for common food items have been extensively measured as surrogate markers of food allergy, and dietary avoidance based on the test results advocated.

Aim: We reviewed the prevalence of specific food IgG and IgA in children with eczema and evaluated outcome of dietary avoidance in these children.

Methods: Specific immunoglobulins of 96 food items were measured for 30 consecutive atopic dermatitis (AD) patients and disease severity [SCORing atopic dermatitis (SCORAD) and Nottingham eczema severity score (NESS)], Children Dermatology Life Quality Index (CDLQI), skin hydration (SH), transepidermal water loss (TEWL), topical corticosteroid and oral antihistamine usage were evaluated. Twenty seven of these patients received dietary avoidance advice based on IgG and IgA data. General acceptability of treatment (GAT) was documented at the end of 3 months.

Results: There were generally no correlations among levels of IgG or IgA of the 96 food items and disease severity, quality of life, SH or TEWL. Two-third patients reported very good or good and one-third reported fair or poor GAT following dietary avoidance advice. There was no difference in any clinical parameters between the two groups following dietary avoidance. Patient with lower sunflower seed IgA (p = 0.043), casein IgG (p = 0.041), milk IgG (p = 0.037) or whey IgG (p = 0.014) had improved SCORAD and objective SCORAD following dietary advice.

Conclusion: Children with AD are sensitized to many food allergens via IgG and IgA mechanisms. Levels of food IgG or IgA do not seem to correlate with any clinical parameters in AD. Subjectively, two third of patients accepted dietary manipulations as very good or good for their AD. Objectively, dietary avoidance had few clinical effects on the clinical parameters. Sensitization should not be generalized to mean allergy to common food.

• Atopic dermatitis
• CDLQI
• childhood eczema
• food avoidance
• IgA
• IgG
• IgE
• NESS
• quality of life
• SCORAD

Acknowledgements

We thank Ms. Tracy Kwong, Assistant Operations Manager of HK BioTek Ltd, for performing the blood tests for us. However, Ms. Kwong is not involved in the statistical inputs and writing of the article.