What are the characteristic features of an eczema rash?

Characteristic Features of an Eczema Rash

An eczema rash is characterized by itchy skin plus at least three of the following features: itchiness in skin creases (like elbow folds or neck), history of asthma/hay fever (or family history in young children), general dry skin, visible flexural eczema, and onset in the first two years of life. 1

Primary Diagnostic Features

Essential Characteristics

• Intense itching (pruritus) - The hallmark symptom that leads to scratching
• Dry skin (xerosis) - General dryness that is present year-round
• Redness (erythema) - Inflamed appearance of affected skin
• Location in flexural areas - Commonly affects folds of elbows, behind knees, front of ankles, around neck, and around eyes
  • In children under 4 years: Often affects cheeks, forehead and outer limbs 1

Morphological Features

• Acute lesions:

  • Red, inflamed patches
  • Vesicles (small fluid-filled blisters)
  • Weeping and crusting when severe
  • Excoriations from scratching

• Chronic lesions:

  • Lichenification (thickened skin with increased skin markings)
  • Scaling and dryness
  • Hyperpigmentation or hypopigmentation
  • Papules (raised bumps)

Distribution Patterns

• Infants: Cheeks, scalp, extensor surfaces of limbs
• Children: Flexural areas (antecubital and popliteal fossae)
• Adults: Flexural areas, hands, neck, face, upper chest

Associated Features

• Temporal pattern: Chronic relapsing-remitting course 2
• Exacerbating factors:
  • Exposure to irritants (soaps, detergents)
  • Temperature extremes
  • Stress
  • Allergens in susceptible individuals 1

Signs of Complications

• Bacterial infection: Crusting, weeping, pustules
• Viral infection (herpes simplex): Grouped, punched-out erosions or vesiculation 1
• Secondary changes: Excoriations from scratching, post-inflammatory pigmentation

Severity Assessment

Severity can be assessed by:

• Extent of body surface area affected
• Intensity of inflammation
• Impact on sleep and daily activities
• Persistence of symptoms

Diagnostic Pitfalls to Avoid

1. Mistaking other red scaly conditions for eczema:

   • Seborrheic dermatitis (greasy scales, less itchy)
   • Psoriasis (thicker, well-demarcated plaques)
   • Tinea (advancing border, central clearing) 3

2. Missing signs of infection:

   • Bacterial infection can worsen previously stable eczema
   • Herpes simplex infection requires prompt recognition and treatment 1

3. Overlooking contact dermatitis:

   • Can develop in patients with previously stable eczema
   • May require patch testing to identify triggers 1

The diagnosis of eczema is primarily clinical, based on the characteristic appearance and distribution of the rash, along with the patient's history. Skin biopsy is generally not helpful for diagnosis 1. Early recognition and appropriate management can significantly improve quality of life and reduce complications from this chronic inflammatory skin condition.