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:
- 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 ||Download (.pdf)
Table 14-1 Features of Atopic Dermatitis
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
Dennie–Morgan folds (accentuated lines or grooves below the margin of the lower eyelid)
Allergic shiners (darkening beneath the eyes)
Hyperlinearity of palms and soles
White dermatographism (white line appears on skin within 1 minute of being stroked with blunt instrument)
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 income and education both ...