What are the characteristic features of an eczema rash?

Characteristic Features of Eczema Rash

Eczema rash is characterized by erythema, papules, vesicles, erosion, infiltration, lichenification, dry skin, and desquamation, with distribution patterns that vary by age and typically affect flexural areas in older children and adults. 1

Key Morphological Features

Eczema presents with three major morphological features:

• Multiple pinpoint lesions: Numerous tiny foci from which individual papules/vesicles arise
• Polymorphism: Combination of various skin changes in the same area
• Intense pruritus: The hallmark "itch that rashes" 2, 3

Acute Eczema Features

• Erythema: Redness of the skin
• Papules: Small raised bumps
• Vesicles: Fluid-filled blisters
• Seropapules: Papules with serous fluid
• Erosion: Superficial loss of skin
• Exudate: Serous fluid that may form crusts
• Weeping/oozing: Especially in infected areas 1, 2

Chronic Eczema Features

• Lichenification: Thickened skin with accentuated skin markings
• Scaling: Flaking of the outer skin layer
• Hyperpigmentation: Darkening of affected areas
• Hypopigmentation: Lightening of affected areas (less common)
• Fissures: Painful cracks in the skin 1, 2, 4

Age-Specific Distribution Patterns

The location of eczema lesions varies significantly by age:

Infants (0-2 years)

• Cheeks and scalp
• Forehead and neck
• Extensor surfaces of extremities
• Note: Diaper area is rarely affected by atopic dermatitis 4

Children (2-12 years)

• Flexural areas (antecubital and popliteal fossae)
• Neck
• Wrists
• Ankles 1

Adolescents and Adults

• Predominantly flexural areas
• Head and neck
• Hands
• May affect eyelids and perioral areas 1, 4

Diagnostic Criteria

According to the British Association of Dermatologists, diagnosis requires:

• Itchy skin condition (or report of scratching in children)
• Plus three or more of:
  • History of itchiness in skin creases
  • History of asthma/hay fever (or atopic disease in first-degree relatives for children under 4)
  • General dry skin in the past year
  • Visible flexural eczema (or eczema on cheeks/forehead in children under 4)
  • Onset in first two years of life 1

Secondary Changes

Infection Signs

• Bacterial infection: Crusting, weeping, punched-out erosions
• Staphylococcal infection: Yellow crusting
• Herpes simplex infection (eczema herpeticum): Grouped vesicles or punched-out erosions 1, 4

Complications

• Excoriations: Due to scratching
• Secondary bacterial infections: Common with Staphylococcus aureus
• Eczema herpeticum: Potentially life-threatening viral complication 4

Histopathological Features

Though not typically needed for diagnosis, histopathology shows:

• Spongiosis: Intercellular edema between keratinocytes
• Overproduction of hyaluronic acid
• Decreased E-cadherin expression
• T-cell infiltration: Th1/Tc1 or Th2/Tc2 depending on the type of eczema 2

Differential Diagnosis

Consider other conditions that may mimic eczema:

• Scabies (look for burrows in finger webs)
• Immunodeficiency states
• Contact dermatitis
• Seborrheic dermatitis
• Psoriasis
• Fungal infections 1, 5

By recognizing these characteristic features of eczema rash, clinicians can make accurate diagnoses and develop appropriate treatment plans for their patients.