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.