Physical Examination Characteristics of Eczema (Atopic Dermatitis)
Eczema on physical examination presents with characteristic features including erythema, papules, erosion, infiltration, lichenification, dry skin, and desquamation, with distribution patterns that vary by age and disease chronicity. 1
Key Physical Findings
Primary Lesions
Secondary Lesions
- Excoriations and crusted erosions due to scratching
- Subacute lesions: Erythematous scaling papules and plaques
- Chronic lesions: Lichenification (thickened skin with accentuated markings) and hyperpigmentation 2
Severity Classification
- Mild eruptions: Primarily mild erythema, dry skin, or desquamation
- Severe eruptions: Erythema, papules, erosion, infiltration, or lichenification 1
Age-Specific Distribution Patterns
Infants (0-2 years)
- Cheeks and scalp
- Forehead and neck
- Extensor surfaces of extremities
- Typically spares the diaper area 2
Children (2+ years)
Adults
- Flexural areas
- Head and neck
- Hands
- May present as head-and-neck dermatitis, chronic hand eczema, multiple areas of lichenification, or prurigo lesions 4
Diagnostic Features
Essential Criteria
- Pruritus (itching) - mandatory feature
- Eczematous lesions with a chronic or relapsing course 1
Supporting Features (3+ required with pruritus)
- History of itchiness in skin creases
- History of asthma or hay fever (or family history of atopy)
- General dry skin (xerosis) in the past year
- Visible flexural eczema (or appropriate distribution by age)
- Onset in the first two years of life 1
Signs of Complications
Infection
- Bacterial infection: Crusting, weeping, or pustules (commonly Staphylococcus aureus)
- Viral infection: Grouped, punched-out erosions or vesicles (herpes simplex virus - eczema herpeticum) 1, 2
Chronic Changes
- Lichenification with hyperpigmentation
- Accentuated skin markings
- Possible hypopigmentation in some cases 3
Polymorphism of Lesions
Eczema demonstrates polymorphism (multiple types of lesions simultaneously), which is a key diagnostic feature. The "eczema triangle" concept describes this composition of erythema, papules, seropapules, vesicles, pustules, scales, and crusts seen in acute eczema 3.
Pitfalls in Physical Examination
- Failure to recognize atypical presentations in adults that may not fit traditional diagnostic criteria 4
- Overlooking secondary infection which can exacerbate symptoms
- Confusing contact dermatitis with atopic dermatitis (may require patch testing to differentiate) 1
- Not recognizing that distribution patterns change with age 2
Remember that physical examination findings should be correlated with the patient's history, including personal or family history of atopy, to establish the diagnosis of atopic dermatitis.