We did a computer-aided search of PubMed from 1990 through May, 2002, for aspects of atopic dermatitis pertinent to this review, to supplement our existing awareness of the primary published work. We searched using the keywords atopic dermatitis and eczema. Because of limitations on the number of citations, we made selections from the 2043 reports published on atopic dermatitis in the past decade to support our interpretations with criteria for assessing experimental studies and
SeminarAtopic dermatitis
Section snippets
Epidemiology
Atopic dermatitis is a major public-health problem worldwide with a lifetime prevalence in children of 10–20%, and a prevalence of 1–3% in adults.3 Prevalence of this disease has increased by two to three-fold during the past three decades in industrialised countries, but remains much lower in agricultural regions such as China, eastern Europe, and rural Africa. Moreover, higher prevalences have been recorded in urban regions than in rural regions of developed countries, and the disease is more
Clinical diagnosis
Atopic dermatitis offers a wide clinical spectrum ranging from minor forms such as pityriasis alba (dry depigmented patches) or hand eczema to major forms with erythrodermic rash. The most common forms include the clinical features listed in panel 1.9 Of the major features, pruritus and chronic or relapsing eczematous lesions with typical shape and distribution are essential for diagnosis. Although pruritus can occur throughout the day, it is usually worse in the early evening and night.
Pathophysiology
Interactions between susceptibility genes, the host's environment, pharmacological abnormalities, and immunological factors contribute to the pathogenesis of atopic dermatitis.10 Most of the progress made in understanding the immunology of this disease is related to the IgE-mediated or extrinsic form of the disease. Clearly, atopic dermatitis has an immunological basis—as confirmed by the observation that primary T-cell immunodeficiency disorders frequently have raised concentrations of serum
Genetics
Atopic dermatitis is a genetically complex, familially transmitted disease with a strong maternal influence. Parental atopic dermatitis confers a higher risk to offspring than does parental asthma or allergic rhinitis, suggesting the existence of genes specific to atopic dermatitis. Several chromosomal regions contain pathophysiologically relevant candidate genes, especially on chromosome 5q31–33 since it contains a clustered family of Th2 cytokine genes—ie, interleukins 3, 4, 5, and 13, and
Foods
Food allergens induce skin rashes in nearly 40% of children with moderate to severe atopic dermatitis.47 Food allergies in patients with atopic dermatitis might induce dermatitis and contribute to severity of skin disease in some patients, whereas in others urticarial reactions, or non-cutaneous symptoms are elicited. Infants and young children with food allergies generally have positive immediate skin tests or serum IgE directed to various foods, especially egg, milk, wheat, soy, and peanut.48
Management
Successful management of atopic dermatitis requires a multipronged approach involving skin care, identification and elimination of flare factors, and anti-inflammatory treatment.73 Randomised controlled trials are especially important in assessing the effects of treating atopic dermatitis because of the substantial placebo effect in this disease.
Future directions
Atopic dermatitis is often the first presentation of an individual destined to a lifetime of allergy and asthma. Since the skin is a highly sensitising organ that contributes greatly to the systemic allergic response, highly effective treatments need to be developed to reduce skin inflammation in this disease. Advances are likely to need better definitions for the various clinical phenotypes of atopic dermatitis, including identification of the genes leading to the disease, a better
Search strategy and selection criteria
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