BACKGROUND
Atopic dermatitis (AD) is a chronic, remitting-relapsing inflammatory skin disorder that presents intense pruritus and varying degrees of recurrent eczematous lesions. In developed countries, the incidence seems to plateau at 10–20% in childhood and at 2-8% in adulthood.1,2 The pathogenesis of AD is complex and not completely explained, caused by a combination of genetic and environmental factors. About 80% of AD patients have increased total IgE and is prevalently sensitized to aeroallergens, mainly house dust mite (HDM), defining the “extrinsic” form of AD. The remaining 20% has normal total IgE, referred to as the “intrinsic” endotype.3 In overall 40–50% of children, AD is usually the first step of the so-called allergic march.4 Due to the multifactorial pathogenesis, there are numerous approaches to therapeutic management mainly based on symptomatic treatments (moisturizers, topical and/or systemic corticosteroids, immunosuppressive molecules). Since recent years, many steps forward are being developed in the use of targeted disease-modifying drugs (e.g., omalizumab, dupilumab). In this context, Allergen-specific Immunotherapy (AIT) is one of such pioneering therapies, introduced in clinical practice more than 100 years ago. Through a mechanism called tolerance, AIT is defined as the practice of administering slowly increasing amounts of the allergen(s) to achieve a hyposensitization, thus reducing the symptoms during the natural exposure to the allergen(s).3,4 Efficacy of AIT is well documented in Hymenoptera venom allergy and allergic rhinitis (AR) and/or asthma, while its role in AD is still under debate, especially in children.