Home Books Fitzpatrick's Dermatology in General Medicine, 8e

Chapter 14. Atopic Dermatitis (Atopic Eczema)

Donald Y.M. Leung; Lawrence F. Eichenfield; Mark Boguniewicz

Atopic Dermatitis at a Glance

Prevalence peak of 15–20% in early childhood in industrialized countries.
A chronic or chronically relapsing disorder with major features of:
- Pruritus;
- Eczematous dermatitis (acute, subacute, or chronic) with typical morphology and age-specific patterns;
- Facial and extensor involvement in infancy; and
- Flexural eczema/lichenification in children and adults.
Commonly associated with the following:
- Personal or family history of atopy (allergic rhinitis, asthma, atopic dermatitis).
- Xerosis/skin barrier dysfunction.
- Immunoglobulin E reactivity.
- Genetic basis influenced by environmental factors with alterations in immunologic responses in T cells, antigen processing, inflammatory cytokines, host defense proteins, allergen sensitivity, and infection.

Atopic dermatitis (AD) is a chronically relapsing skin disease that occurs most commonly during early infancy and childhood. It is frequently associated with abnormalities in skin barrier function, allergen sensitization, and recurrent skin infections. There is no single distinguishing feature of AD or a diagnostic laboratory test. Thus, the diagnosis is based on the constellation of clinical findings listed in Table 14-1.1

Table 14-1 Features of Atopic Dermatitis

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Table 14-1 Features of Atopic Dermatitis

Major Features

Pruritus

Rash on face and/or extensors in infants and young children

Lichenification in flexural areas in older children

Tendency toward chronic or chronically relapsing dermatitis

Personal or family history of atopic disease: asthma, allergic rhinitis, atopic dermatitis

Other Common Findings

Dryness

Dennie–Morgan folds (accentuated lines or grooves below the margin of the lower eyelid)

Allergic shiners (darkening beneath the eyes)

Facial pallor

Pityriasis alba

Keratosis pilaris

Ichthyosis vulgaris

Hyperlinearity of palms and soles

White dermatographism (white line appears on skin within 1 minute of being stroked with blunt instrument)

Conjunctivitis

Keratoconus

Anterior subcapsular cataracts

Elevated serum immunoglobulin E

Immediate skin test reactivity

Since the 1960s, there has been a more than threefold increase in the prevalence of AD.2 AD is a major public health problem worldwide, with a prevalence in children of 10–20% in the United States, Northern and Western Europe, urban Africa, Japan, Australia, and other industrialized countries.3 The prevalence of AD in adults is approximately 1–3%. Interestingly, the prevalence of AD is much lower in agricultural regions of countries such as China and in Eastern Europe, rural Africa, and Central Asia. However, the most recent data from the International Study of Asthma and Allergies in Childhood (ISAAC) Phase Three study confirms that AD is a disease with high prevalence, affecting patients in both developed and developing countries.4 There is also a female preponderance for AD, with an overall female/male ratio of 1.3:1.0.

The basis for this increased prevalence of AD is not well understood. However, wide variations in prevalence have been observed within countries inhabited by similar ethnic groups, suggesting that environmental factors are critical in determining disease expression. Some of the potential risk factors that may be associated with the rise in atopic disease include small family size, increased ...

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