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Background: Atopic dermatitis is the most common skin disease in children, with a prevalence of 10% to 15%, and is common in adults as well. Close coordination between primary care physicians and specialists is essential for the adequate treatment of chronically and severely affected patients.

Methods: This article is a review of pertinent publications that were retrieved by a selective search in Pubmed, with additional consideration of the guidelines of the Association of Medical Scientific Societies in Germany (AWMF) and the European Dermatology Forum.

Results: Trigger factors such as skin irritants, allergens, microbial pathogens, and psychological factors can affect the condition of the skin differently in individual patients and should be individually assessed. The use of skin moisturising creams or emollients along with avoidance of specific and unspecific irritants is of great importancel, as these patients have an impaired cutaneous barrier. Topical anti-inflammatory treatment with glucocorticoids or calcineurin inhibitors is a central part of the management of atopic dermatitis; in exceptional cases, severely affected patients are treated with systemic anti-inflammatory drugs. Interdisciplinary patient education has been found to be an effective tool in the complex management of this disease. Chronically and severely affected patients present special challenges for diagnosis and treatment.

Conclusion: Recent advances in the understanding of the molecular basis of cutaneous barrier disorders and of congenital and acquired immune disorders have led to new approaches to the treatment of atopic dermatitis.

Atopic dermatitis (atopic eczema) is the most common skin disease in children with a prevalence of 10–15% before school age. About half of the patients suffer from moderate to severe atopic dermatitis. Spontaneous healing can occur at any time but 1–2% of adults are also affected. The disease is of great economic importance because it is so common and generally chronic (2, e1). Frequently, the dermatitis is associated with other atopic diseases such as food allergies, asthma, and allergic rhinitis. The prevalence of food allergies in patients with severe atopic dermatitis is believed to be around 30%.

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The clinical features of atopic dermatitis vary depending on the stage (acute or chronic) of the disease and the age of the patients (Table 1). The most disabling feature is generally the chronic or chronic-recurrent pruritus; another significant cause of suffering is the associated social stigmatization. The course of the disease is highly variable with flares of varying severity and duration. Even what appears to be mild manifestations can greatly disturb the patient and cause emotional stress. Patients with atopic dermatitis are significantly more often depressed or anxious than healthy control groups, which may be a result of their suffering. Infections are a common complication of atopic dermatitis and can be quite severe (Figures 1 and 2, Box 1).

Both genetic predisposition (skin barrier defects as well as impaired innate and acquired immunity) and trigger factors play important roles in both the onset of atopic dermatitis and the exacerbations. Filaggrin loss-of-function mutations have received special attention in recent years. Filaggrin is a structural protein in differentiated keratinocytes. Loss-of-function mutations in filaggrin lead to skin barrier defects, reduced bacterial defenses, and an increased skin pH value. Filaggrin mutations are associated with an increased risk to develop atopic dermatitis (Odds Ratio 3.1–4.8). About 25% of patients with atopic dermatitis have such mutations. Moreover, these patients are at increased risk of developing allergies and asthma, as well as eczema herpeticum, which is known to be a severe complication of atopic dermatitis.

The decreased incidence of infections in early childhood led to the so-called ‘hygiene hypothesis' by David Strachan, which has been implicated in recent decades with the increased prevalence of atopic dermatitis (4–8-fold increase, depending on study); the same trend has been seen in other atopic disorders.

The clinical picture of dermatitis (cutaneous inflammation with epidermal involvement) results from the presence of T cells, IgE-binding antigen-presenting dendritic cells and eosinophils.

In the acute and subacute stages, a variety of mediators, especially the TH2 cytokines such as interleukin 4 (IL-4) and interleukin 13 (IL-13), are responsible for the transient down-regulation of barrier proteins.

The German AWMF S3 guidelines No. 61–13 on allergy prevention (Allergiepr?vention) give the current recommendations for dietary and preventive measures for high-risk families. The recommendations include 4 months of breast feeding (or the use of extensive protein hydrolysate formulas) and the early introduction of fish in the child’s diet. According to the 2009 version of the same German guidelines, age-appropriate solid foods should be started during the first year even in children at high risk for allergies.

The diagnosis is usually made clinically. Both a detailed history with special attention paid to personal and family history of atopic disorders and a complete physical exam are required.

A skin biopsy is generally not needed if the history and clinical features are typical, but may be useful for differential diagnostic purposes on occasion. The most common differential diagnostic considerations, including other forms of dermatitis such as allergic or irritant contact dermatitis, nummular dermatitis, and in adults an early stage of cutaneous T-cell lymphoma usually cannot be excluded microscopically. Hand dermatitis may often reflect a mixed picture of atopic, irritant and allergic contact dermatitis; it is generally difficult to classify precisely on the basis of etiology. When atopic dermatitis affects the hands and feet, both palmoplantar psoriasis and dermatophyte infections must be excluded. Less commonly one may encounter syndromes or immunodeficiencies which can resemble atopic-dermatitis-like changes (Box 2). Several other inflammatory (also infectious) diseases of the skin, such as scabies in childhood, can occasionally be confused with atopic dermatitis.

When atopic dermatitis is suspected, it is necessary to be aware of possible psychosomatic factors, as well as dietary or environmental trigger factors. The importance of trigger factors varies greatly among individuals, but their identification and then avoidance or reduction are a key part of an individualized treatment approach. One must also be aware of the decreased sensitivity treshold for unspecific skin irritation due to the impaired barrier function.

Both infections and immunizations can cause exacerbations of atopic dermatitis. Nonetheless, according to the Standing Committee on Vaccination Recommendations (STIKO), both children and adults with atopic dermatitis should be immunized. In case of acute exacerbations, vaccinations should be avoided until the skin stabilizes (German AWMF S2 guideline 013–027 on atopic dermatitis [Neurodermitis]).

由MediCool醫(yī)庫軟件馮飛飛 編譯，上海市皮膚病醫(yī)院陳裕充博士審核

原文來自：Dtsch Arztebl Int 2014; 111: 509?20