dermatologic disorders
Atopic Dermatitis (Eczema)
Etiology of Atopic Dermatitis
Atopic dermatitis primarily affects children in urban areas or high-income countries, and prevalence has increased over the last 30 years; up to 20% of children and 10% of adults in high-income countries are affected. Most people with the disorder develop it before age 5, many of them before age 1; however, atopic dermatitis may even begin during late adulthood. The unproven hygiene hypothesis suggests that decreased early childhood exposure to infectious agents (ie, because of more rigorous hygiene regimens at home) may increase the development of atopic disorders and autoimmunity to self-proteins. Many patients or their family members who have atopic dermatitis also have allergic Asthma and/or immediate-type hypersensitivities that manifest, for example, as allergic seasonal or perennial rhinoconjunctivitis. The triad of atopic dermatitis, allergic rhinoconjunctivitis, and asthma is called atopy or atopic diathesis. Other dermatologic features of atopy include 