What is the medical term for eczema?

Medical Term for Eczema

The medical term for eczema is atopic dermatitis (AD), a chronic, pruritic inflammatory dermatosis that affects up to 25% of children and 2-3% of adults 1.

Definition and Characteristics

• Atopic dermatitis is a chronic inflammatory skin condition that follows a relapsing and remitting course, occurring most frequently in children but also affecting adults 2
• Approximately 60% of patients develop symptoms in the first year of life and 90% by 5 years of age 2
• The prevalence of AD has increased dramatically in recent decades, now affecting 10-20% of children and 2-3% of adults worldwide 2

Pathophysiology

• AD results from complex interactions between genetic factors, environmental exposures, skin barrier dysfunction, and immunological derangement 2
• Key mechanisms involve:
  • Skin barrier abnormalities with increased transepidermal water loss 2
  • Immune system dysregulation with Th2 cell activation in acute phase and additional Th1 response in chronic phase 3
  • Genetic predisposition, evidenced by family history of atopic diseases 3

Diagnostic Criteria

The diagnosis of atopic dermatitis is primarily clinical, based on:

• An itchy skin condition (or report of scratching in a child) plus three or more of the following 1:
  • History of itchiness in skin creases such as folds of the elbows, around neck (or the cheeks in children under 4 years)
  • History of asthma or hay fever (or history of atopic disease in a first-degree relative in children under 4 years)
  • General dry skin in the past year
  • Visible flexural eczema (or eczema affecting the cheeks or forehead and outer limbs in children under 4 years)
  • Onset in the first two years of life (not always in children under 4 years)

Subtypes

• Atopic dermatitis can be divided into atopic and non-atopic subtypes 4:
  • Atopic eczema: characterized by high levels of total IgE, positive skin prick tests, and detectable specific IgE antibodies 4
  • Non-atopic eczema: characterized by low levels of total IgE, negative skin prick tests, and undetectable specific IgE antibodies (estimated to represent 10-45% of eczema cases) 4

Clinical Presentation

• The clinical presentation varies based on age, skin type, ethnicity, and comorbid conditions 5
• Often referred to as "the itch that rashes" due to the intense pruritus that precedes or accompanies skin lesions 5
• The self-perpetuating itch-scratch cycle worsens inflammation and skin barrier damage 3
• Age-specific distribution patterns are common, with facial and extensor involvement in infants, and flexural involvement in older children and adults 2

Terminology Note

While "eczema" is commonly used in clinical practice, according to the Nomenclature Review Committee of the World Allergy Organization, "atopic dermatitis" is the preferred medical term for this specific condition 4.