IgG food hypersensitivity: A potential hidden precipitant for chronic spontaneous urticaria A case report

While the link between foods and chronic spontaneous urticaria (CSU) is controversial, many immunological mechanisms have been proposed to establish a causal relationship.To explore the potential benefit of avoiding immunoglobulin G (IgG)-mediated food hypersensitivity as a triggering factor in a case with CSU.The patient is a 50-year-old woman who complained of CSU for 1 and half year, which responded partially and temporarily to antihistamine medications. Of interest, it started 6 months after she followed an oat-rich diet. Her Urticaria Activity Score 7 was 23 out of 40.Specific immunoglobulin E responses to common food and inhalant allergens were negative. A food-specific IgG antibody test was conducted, and it was mainly elevated for chicken eggs, rye, sweet pepper, gluten, garlic, wheat, and pineapple. Avoiding these foods had a curative effect on the CSU over a 2-month period.To the best of our knowledge, this is the first case report of symptoms of CSU that resolved after identifying and avoiding food items with IgG antibodies. Furthermore, well-controlled studies are advocated to verify the potential role of IgG food hypersensitivity in the pathogenesis of CSU.