What are the key components of a physical exam for atopic dermatitis?

Physical Examination of Atopic Dermatitis

The physical examination of atopic dermatitis should focus on identifying key clinical findings including erythema, edema, xerosis, erosions/excoriations, oozing and crusting, and lichenification, with distribution patterns varying by patient age and chronicity of lesions. 1

Key Components of Physical Examination

Morphology of Skin Lesions

• Acute lesions: Erythematous papules and serous exudates 2
• Subacute lesions: Erythematous scaling papules and plaques 2
• Chronic lesions: Lichenification (thickened skin with accentuated skin markings) and hyperpigmentation 2
• Secondary lesions: Excoriations and crusted erosions due to scratching 2

Distribution Patterns by Age

• Infants (0-2 years):

  • Cheeks, scalp, forehead, and neck
  • Extensor surfaces of extremities
  • Notably, diaper area is rarely affected 2

• Children (2-12 years):

  • Flexural areas (antecubital and popliteal fossae)
  • Neck, wrists, and ankles 1

• Adolescents and Adults:

  • Predominantly flexural areas
  • Head and neck involvement
  • Hands and feet may be affected 1, 2

Assessment of Disease Severity

The examination should evaluate:

1. Extent of involvement: Body surface area (BSA) affected 3
2. Intensity of lesions: Degree of erythema, edema/papulation, excoriation, lichenification 3
3. Distribution: Characteristic age-dependent patterns 1
4. Pruritus: A hallmark symptom that should be assessed for intensity 1, 4

Special Examination Considerations

Skin Color Variations

• Erythema may be difficult to assess in darker skin types
• Hyperpigmentation and lichenification may be more prominent in skin of color
• Follicular accentuation may be more common in darker skin types 5

Evaluation for Complications

• Secondary infections: Look for:

  • Crusting, weeping, or pustules (bacterial infection)
  • Vesicles with punched-out erosions (viral infection - eczema herpeticum) 1, 2

• Contact dermatitis: Consider when there is:

  • Marked facial/eyelid involvement
  • Increased severity at neck flexures
  • Vesicular lesions on dorsal hands and fingertips 1

Differential Diagnosis Considerations

During examination, look for features that might suggest alternative diagnoses:

• Seborrheic dermatitis: Affects groin and axillary regions (typically spared in AD) 1
• Allergic contact dermatitis: May have unusual distribution patterns (e.g., sides of feet) 1
• Scabies: Look for burrows, especially in web spaces between fingers
• Psoriasis: Well-demarcated plaques with silvery scale

Documentation Recommendations

For comprehensive documentation and monitoring, consider using validated assessment tools:

• Eczema Area and Severity Index (EASI)
• SCORing Atopic Dermatitis (SCORAD)
• Body Surface Area (BSA)
• Patient-Oriented Eczema Measure (POEM) 3

Common Pitfalls to Avoid

• Overlooking contact dermatitis: ACD is common in AD patients (6-60%) and should be considered when distribution is unusual or there's poor response to therapy 1
• Missing secondary infections: Always examine for signs of bacterial or viral superinfection 2
• Inadequate assessment of pruritus: This is the hallmark symptom that significantly impacts quality of life 1, 4
• Focusing only on visible lesions: Remember to examine for xerosis (dry skin) even in uninvolved areas 1

The physical examination findings, combined with the patient's history, form the basis for diagnosis as there are currently no reliable biomarkers that can distinguish AD from other entities 1.