Atopic dermatitis is a genetically transmitted, chronic inflammatory skin disease that affects 10% to 20% of children and 1% to 3% of adults. J. The vast majority of patients develop the disease before the age of 5 years, although it can also present in adulthood. Atopic dermatitis is the first manifestation of atopy in many patients who later develop allergic rhinitis and/or asthma, a pattern that has been referred to epidemiologically as "the atopic march." Pruritus, scratching, and chronic and/or relapsing eczematous lesions are major hallmarks of the disease. In infants and young children, there is a characteristic pattern of involvement of the face, neck, and extensor skin surfaces. In older children and adults, the skin lesions often involve lichenification and are usually localized to the flexural folds of the extremities. Factors that may exacerbate symptoms in atopic dermatitis patients include temperature, humidity, irritants, infections, food, inhalant and contact allergens, and emotional stress. Food allergy has been implicated in approximately one third of children with atopic dermatitis, although specific IgE is often present without clear relevance to the disease process. The pathogenesis of atopic dermatitis involves a complex interaction between genetic and environmental factors. Xerosis, scratching, and both colonization2,6-8 and infection of the skin by Staphylococcus aureus all contribute to the disease process. As with allergic rhinitis and asthma, the inflammatory reaction in atopic dermatitis involves TH2 lymphocyte activation, resulting in the production of IL-4, IL-5, and IL-13. Other cells involved in this inflammation include IgE-bearing Langerhans cells, atopic keratinocytes, lymphocytes, monocytes/macrophages, eosinophils, and mast cells. The diagnosis of atopic dermatitis is based on its clinical presentation rather than diagnostic testing. However, the judicious use of percutaneous skin tests or in vitro testing for the presence of specific IgE to relevant allergens is a sensitive way of identifying potential allergic triggering factors. Double-blind food challenges are sometimes necessary to determine the relevance of specific food ingestion to symptoms. The effective management of atopic dermatitis involves some combination of trigger avoidance, measures to restore skin barrier function, and anti-inflammatory medication. Trigger avoidance should be individualized based on a careful history and the results of specific IgE testing. Barrier function can be improved by careful hydration and emollient application, such as soaking in a lukewarm bath for 20 to 30 minutes followed by the immediate application of an emollient. There are multiple anti-inflammatory medication options available for treating atopic dermatitis. Topical corticosteroids are appropriate for the vast majority of patients, and the potency of the corticosteroid agent chosen should be individualized based on the severity of the dermatitis, the location of the affected skin, the surface area of the affected skin, and the age of the patient. Clinical exacerbations may require temporarily switching to a more potent topical agent or using a tapering course of a systemic corticosteroid. Tacrolimus and pimecrolimus are anti-inflammatory calcineurin inhibitors and alternatives to corticosteroids that have been recently approved for topical use in adults and children with atopic dermatitis. These agents interrupt activation of lymphocytes and other inflammatory cells, and to date they have been very well tolerated. There are a variety of other treatment options for patients with severe or refractory atopic dermatitis. These include wet dressings and occlusion, phototherapy, systemically administered immunosuppressants such as cyclosporin or interferon gamma, and antimetabolites. In rare cases, short-term hospitalization is a useful way to temporarily reduce exposure to environmental and emotional triggers while initiating intensive patient education, diagnostic testing (such as skin testing and food challenges), and aggressive medical treatment.
ASJC Scopus subject areas
- Immunology and Allergy
- Pulmonary and Respiratory Medicine