Dermatitis, Atopic

Key Features

• Results from an interaction among susceptibility genes, the host environment, skin barrier defects, pharmacologic abnormalities, and immunologic response

• The case for food and inhalant allergens as specific causes of atopic dermatitis is not strong

• There is significant evidence that a primary defect in atopic dermatitis is an abnormality in the skin barrier formation due to defects in the filaggrin gene

Clinical Findings

• Many (not all) patients go through three clinical phases

  • Infantile

  • Childhood or flexural

  • Adolescent

• Infantile eczema

  • Begins on the cheeks and scalp and frequently expresses itself as oval patches on the trunk, later involving the extensor surfaces of the extremities.

  • Usual age at onset is 2–3 months

  • Phase ends at age 18 months to 2 years

• Childhood or flexural eczema

  • Only one-third of all infants with infantile eczema progress to childhood or flexural eczema

  • Predominant involvement is in the antecubital and popliteal fossae, the neck, the wrists, and sometimes the hands or feet

  • Phase lasts from age 2 years to adolescence

• Adolescent eczema

  • Only one-third of children with typical flexural eczema progress to adolescent eczema

  • Manifests with continuation of chronic flexural eczema along with hand and/or foot dermatitis

• Atopic dermatitis unusual after age 30 years

Diagnosis

• Clinical

Treatment

• Acute stages

  • Application of wet dressings and medium-potency topical corticosteroids for acute, weeping atopic eczema

  • Appropriate systemic therapy may be necessary for superinfection with Staphylococcus aureus, Streptococcus pyogenes, or herpes simplex virus

• Chronic stages

  • Avoiding irritants and restore water to the skin

  • No soaps or harsh shampoos should be used

  • Avoid woolen or any rough clothing

  • Bathing is minimized to every second or third day

  • Twice-daily lubrication of the skin is very important

  • A bedroom humidifier is often helpful

  • Tacrolimus and pimecrolimus ointments are topical immunosuppressive agents that are effective