• Clinical science

Atopic dermatitis (Atopic eczema)

Abstract

Atopic dermatitis (AD) is an inflammatory skin disease that typically manifests for the first time in early childhood. Although it often improves during adolescence, it may also become a chronic condition that extends into adulthood. Atopic dermatitis is often associated with other atopic diseases, such as asthma or allergic rhinitis. Although the underlying etiology is not completely understood, genetic components as well as exogenous and endogenous triggers are believed to play a role. The main symptoms of atopic dermatitis include severe pruritus and dry skin. Primary treatment involves managing the pruritus and moisturizing the skin. Topical steroids and calcineurin inhibitors may be added if treatment with moisturizers is insufficient. In severe cases, systemic therapy with steroids is required. The main complication of atopic dermatitis is the development of secondary infections.

Epidemiology

  • About 10–15% of all children are affected
    • Onset of symptoms usually occurs between 3–6 months of age
  • Disease often improves with age

References:[1]

Epidemiological data refers to the US, unless otherwise specified.

Etiology

The etiology of atopic dermatitis is not completely understood. However, genetic factors (polygenic inheritance) as well as exogenous and endogenous triggers may play a role.

  • Genetics (polygenic inheritance)
    • Inherited predisposition for increased IgE formation and sensitization
    • Approx. 70% of patients have a family history of atopic disease; (including eczema, asthma, allergies)
  • Triggers
    • Exposure to indoor dust
    • Heat
    • Extremely dry or humid climate
    • Emotional stress
    • Infections
    • Skin irritation
  • Further theories
    • Impaired skin barrier (permits entry of pathogens)
    • Imbalance between Th1- and Th2-lymphocytes (dominance of Th2-lymphocytes)
    • Impairment of neurovegetative functions

References:[2][3]

Clinical features

  • Main symptoms: intense pruritus and dry skin
  • Infantile AD (age < 2 years)
    • Eczema: over the cheeks, face, head, and extensor surfaces of the extremities that usually spares the diaper area
    • May begin as cradle cap
    • Dennie-Morgan fold: increased folds below the eye
    • Occasionally, lesions appear on the trunk
  • Childhood AD (age 2 to 12 years)
    • Eczema: flexural creases (antecubital and popliteal fossae), skin folds, extensor surface of hands
    • Lesions usually become lichenified (lichenification; is thickening of the skin with accentuated skin markings)
  • Adult/adolescent AD (age > 12 years)

Associated findings

The symptoms of atopic dermatitis are variable and often change in the course of a lifetime - itching and dry skin are usually the main symptoms!

References:[4][4][5][1][6]

Diagnostics

The diagnosis of atopic dermatitis is usually based on patient history and clinical appearance. The American Academy of Dermatology suggests the use of several criteria that need to be fulfilled in order to establish the diagnosis, the most important of which are listed below:

Assessing the severity

References:[7]

Differential diagnoses

References:[1][8]

The differential diagnoses listed here are not exhaustive.

Treatment

  • Avoid triggers:
    • Allergic trigger factors (pets, dust mites, pollen, certain foods)
    • Irritants (clothing, chemicals)
    • Heat
  • Keep the skin moist
  • Breast feeding recommended during infancy
  • Manage/eliminate stress

Management of AD based on disease severity

Mild AD Moderate AD Severe AD
  • Emollients
  • Topical steroids (mild potency)

References:[7][9][10]

Complications

  • Secondary infections
    • Bacterial: staphylococcal skin infections
    • Viral: eczema herpeticum
    • Mycosal: tinea (especially Trichophyton rubrum)
  • Psychosocial complications
    • Sleep problems
    • Decreased quality of life

References:[11][12]

We list the most important complications. The selection is not exhaustive.

Prognosis


References:[1]