The Evolution of IgE-Based Allergy Testing in Atopic Dermatitis: Where Do We Stand?

The pathophysiology of atopic dermatitis (AD) involves cutaneous inflammation, predominantly mediated by innate immunity and T cells, with Immunoglobulin E (IgE) playing a marginal role in most patients. Over previous decades, however, there has been an ongoing debate regarding the relevance of IgE-mediated allergy testing in AD patients. Patients with AD have a defective skin barrier that facilitates a high inflammatory response to environmental antigens, placing them at greater risk for food allergies. Nevertheless, because these patients often produce very high levels of IgE, the positive predictive value of skin prick tests and specific IgE measurements is low; such tests should be performed only when there is a concordant immediate hypersensitivity reaction (i.e. urticaria or angioedema) rather than eczema. In recent years, numerous studies have emphasized the importance of maintaining oral exposure to foods in order to prevent the development or progression of food allergies in atopic patients. While acknowledging that food allergens may contribute to AD in certain cases, it is critical that patients understand the risk of developing IgE-mediated food allergies if they exclude allergenic foods from their diet. Ultimately, controlling AD while retaining these foods in the diet should be the goal for all patients.