Managing atopic dermatitis in children and adults

Nurse Practitioner, Apr 2000 by Nicol, Noreen Heer

ABSTRACT

Although the etiology of atopic dermatitis is not well understood, it appears to be linked to a combination of genetic and environmental factors, and it is usually associated with other atopic diseases such as asthma and hay fever. A definitive diagnosis in children and adults depends on identifying the nature and distribution of the lesions and on eliciting a personal or family history of the disease. Although no cure exists, atopic dermatitis of ten resolves spontaneously and can be controlled through proper management. Avoiding factors that precipitate or exacerbate inflammation is key to preventing disease flares. In children and adults, hydration and topical corticosterolds are the mainstays of therapy. Current advances in understanding the immunologic basis of the disease have led to the development of highly effective new treatments. Using patient education and support, the clinician can help adults and children successfully manage their disease.

Atopic dermatitis is a common skin inflammation believed to be part of a larger family of atopic disease; it is often the first sign of a predisposition to allergic disease.1 The primary characteristic of atopic dermatitis is intense pruritus, which can be disfiguring in its severe forms. Atopic dermatitis is chronic, with a relapsing and remitting course. It is frequently exacerbated by environmental factors, rendering it a challenge to treat. Although a cure does not exist, it can be controlled in most patients with pharmacologic treatment and adherence to preventive measures. Atopic dermatitis can have a profound effect on the patient's quality of life, and the psychological aspects of the disease should not be ignored.2-4 Educating the patient and the patient's family or caregiver promotes treatment adherence and helps the patient more ef fectively cope with the disease.

Epidemiology

The prevalence of atopic dermatitis has tripled in the past 30 years, and the condition affects about 10% of the U.S. population at some point in their lifetime. S,6 The reason for the increase is not known, but a parallel increase has occurred in the incidence of asthma, suggesting that an environmental trigger may be responsible.6

Atopic dermatitis is most common in children, accounting for 1 % of all pediatric visits and 20% of pediatric dermatology visits.' Up to 75% of atopic dermatitis patients exhibit signs of the disease by age 6 months, and 80% to 90% develop the disease by age 5. 8,9 Atopic dermatitis resolves spontaneously by adolescence in 40% to 75% of patients.9

Atopic dermatitis is usually associated with other allergic conditions. Asthma, hay fever, or both develop in 40% to 50% of atopic dermatitis patients, and 50% to 60% of patients report a family history of one or more atopic diseases.8,10,11 According to one study, when both parents have atopic dermatitis, the offspring have an 80% chance of developing the disease.12

Pathogenesis

Structural Abnormalities

The barrier function of the skin is impaired in patients with atopic dermatitis.13 Changes in the lipid content cause increased water loss from the epidermis, reducing the water content and pliability of the skin. The skin is chronically dry, leading to a greater risk of penetration of environmental irritants. The increased Langerhans' cells in the epidermis and the number of high-affinity IgE receptors on these cells amplify the cells' ability to present IgE-targeted allergens to allergen-specific T cells.11 Finally, the pruritus threshold of the skin is reduced, perhaps as a result of changes in the number and neuropeptide content of dermal nerve endings.14

Immunologic Abnormalities

Excessive levels of IgE, one of the characteristic findings of atopic dermatitis, are present in 80% to 85% of patients.15 A dysregulation in cytokine production results in a shift in the profile of T-helper cells. Subsequently, this shift causes interleukin (IL)-4 and IL-5 overproduction, which stimulates B-cell production of IgE and eosinophils. Simultaneously, the production of IL-2 and interferon is disrupted.7,19,16

ClInIcal Features

The initial clinical feature of atopic dermatitis is skin dryness and roughness, which presents as early as the first month of life. Erythema, papules, and pruritus may develop after additional irritation. The intense pruritus and subsequent scratching play an important role in developing the cutaneous lesions in atopic dermatitis.14 Atopic dermatitis presents in one of three stages: acute, subacute, or chronic (see Table 1 and Figure 1).

The pattern of atopic dermatitis lesions varies according to age. In the infantile stage, lesions are distributed over the forehead, cheeks, and scalp and then spread to the neck, trunk, and extensor surfaces of the extremities. Lesions do not generally spread to the diaper area.17 Lesions tend to be of the acute type and are typically moist, oozing, and crusting. Chronic lesions with lichenification do not appear until several weeks later when the infant is able to scratch, which generally occurs at age 2 months.