Excerpt from Dermatitis, Atopic

Synonyms, Key Words, and Related Terms: eczema, ichthyosis vulgaris, keratosis pilaris, hand and foot dermatitis, keratoconus, chronic pruritic skin condition, fishlike scales, horny follicular papules, fissuring of the palms, fissuring of the soles, facial erythema, pityriasis alba, increased palmar linear markings, dry skin, infraorbital fold, Dennie-Morgan line, pilaris, perioral pallor

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Background: Atopic dermatitis (AD) is a chronic, highly pruritic, eczematous skin disease that follows patients from early childhood into puberty and sometimes adulthood. Also referred to as eczematous dermatitis, the disease often has a remitting/flaring course, which may be exacerbated by social, environmental, and biological triggers.

Atopic dermatitis is characterized as an immediate (type I) hypersensitivity reaction similar to that of allergic rhinitis, bronchial asthma, atopic dermatitis, and food allergy. Although not all patients who have atopic dermatitis are atopic (a misnomer of the disease), the correlation is high, around 80%, and patients with AD often manifest other atopic diseases.

Pathophysiology: The exact etiology of AD is unknown. It is immunologically mediated, with a large majority of affected patients having elevated serum immunoglobulin E (IgE) concentrations, although no relationship exists between IgE levels and severity of disease. A strong familial inheritance pattern seems to exist for both AD and other atopic diseases, with more than half of patients with AD reporting a family history of respiratory atopy.

Researchers are continuing to examine the role that chromosomal markers (chromosomal 11), eosinophilia, cell-mediated immunity, interleukins, and other inflammatory mediators play in the pathophysiology of AD.

Frequency:

In the US: Prevalence of AD ranges from approximately 7-17% in children. A small percentage of affected children will have the disease into adulthood.

Internationally: Studies in Japan and Northern Europe have found similar prevalence, with industrialized and westernized nations noting increasing trends of patients with AD.

Mortality/Morbidity: This disease itself is not life threatening.

Sex: Some studies have found a higher incidence, although not statistically significant, in females, although females do seem to have a worse prognosis.

Age: AD typically manifests in infants aged 1-6 months. Approximately 60% of patients experience their first outbreak by age 1 year and 90% by age 5 years. Disease manifestations can be divided into 3 stages: acute, subacute, and chronic. Onset of AD in adolescence or later is uncommon and should prompt consideration of another diagnosis.