Eczema: Itching to Know More?

Quick facts!

  • Eczema (aka atopic dermatitis) is a chronic pruritic inflammatory skin disease
  • Presentation highly variable based on age and severity
  • Occurs most often in children, but also affect adults
  • Associated with Personal/Family Hx of atopy (eczema, asthma, or allergic rhinitis)
  • Associated with elevated serum IgE (up to 80% of patients)
  • Onset often before age 5yo (~60% by age <1yo; ~85% by age 5yo)
  • ~50% of patients diagnosed in childhood will have persistent eczema

Epidemiology

Affects 5-20% of children worldwide; 11-15% of children in the US

  • Limited data on prevalence in adults (7.3% in a cross-sectional study
    from 2019 with ~1300 adults in the US)

May occur in any geographic location

  • Higher incidence in Western societies, developed countries, and urban areas
  • Increasing incidence in Africa, Eastern Asia, Western Europe, and parts of Northern Europe

30-80% of patients are sensitized to certain foods


Risk factors

+Family Hx of atopy present in ~70% patients

  • Children with 1 atopic parent have a 2-3-fold ↑ risk; children with 2 atopic parents have a 3-5 fold ↑ risk

Loss-of-function mutations in filaggrin (FLG) gene involved in skin barrier function

Potential protective factors: early exposure to endotoxins, dogs, farm animals, or daycare


Pathophysiology

Characterized by epidermal changes:

  • Spongiosis – epidermal edema → stretching of intercellular attachments → rupture → vesicles
  • Acanthosis – stratum spinosum overgrowth
  • Hyperkeratosis – corneous skin layer hypertrophy

Characterized by lymphohistiocytic infiltrate in dermis

Acute phase primarily characterized by spongiosis

Multifactorial causes:

  • Skin barrier deformities
  • Innate immunity response abnormalities
  • Th2-skewed adaptive immune response
  • Altered skin resident microbial flora

General features

Most common features: dry skin + severe pruritus

Cutaneous hyperreactivity to environmental stimuli: allergens, irritants, infections, changes to physical environment or stress

Acute Eczema: 

  • Very pruritic erythematous papules/vesicles
  • Exudation or crusting

Subacute/Chronic Eczema: 

  • Dry, scaly, or excoriated erythematous papules

Chronic Eczema:

  • Skin thickening, fissuring

Clinical features vary by age!

0-2yo:

  • Erythematous, pruritic, scaly lesions
  • Possible vesicle formation
  • Serous exudates and crusting in severe cases
  • Extensor surfaces, scalp, or cheeks
  • SPARES the diaper area

2-16yo:

  • Less exudation, more lichenification
  • Flexural surfaces
    • Antecubital and popliteal fossae, volar wrists, ankles, and neck

Adults:

  • More lichenified and localized
  • Flexural surfaces

Classification


Diagnosis

Eczema is a clinical diagnosis: hx, skin lesion appearance/distribution, associated clinical signs

1 MANDATORY CRITERIA: pruritic skin by observation or report

≥3 MAJOR CRITERIA:

  • Hx of skin crease involvement
  • Hx of asthma or hay fever OR Hx of atopic disease in 1° relative for child <4yo
  • Visible dermatitis involving flexural surfaces
    • IF <4yo, dermatitis affecting the forehead, cheeks, and outer aspects of extremities
  • Grossly dry skin within the past year
  • Symptoms starting in a child <2yo

Lab testing and skin biopsy not routinely used or recommended


Differential diagnosis

  • Allergic/Irritant Contact Dermatitis: exposure history, specific skin area localization, relevant patch test
  • Seborrheic Dermatitis: erythematous patches with greasy scale, scalp involvement, little to no pruritus
  • Psoriasis: well-demarcated erythematous patches, little scale, diaper area involvement
  • Scabies: vesicopustules on palms/soles, skin fold and diaper area involvement
  • Drug reactions
  • Nutritional deficiencies
  • Primary immunodeficiencies (e.g. Hyperimmunoglobulin E Syndrome, Wiskott-Aldrich syndrome)
  • Cutaneous T Cell Lymphoma

Treatment

Check out the 2014 guidelines from the AAD on topical therapies and systemic agents!

Avoid potential triggers: irritants, inhaled allergens, foods, stress

Topical Moisturizers – hydration! 

  • Bathe → gently pat dry skin → apply moisturizer on wet skin

Topical Steroids – anti-inflammatory!

  • Apply to active affected areas of rash
  • May have side effect of skin thinning
  • Recommend NOT using on face, groin area, or underarms

Topical Immunomodulators – anti-inflammatory (second-line)

  • May be used on face and eyelids

Antihistamines may promote sleep, but AVOID topical antihistamines as they
can actually worsen the rash

Wet-Wrap Therapy

  • Soak skin in warm water for 15-20 mins → pat dry → apply topical meds on rash → apply wet dressing on top of rash → apply dry wrap over wet dressing → wrap for 2-6 hrs
  • Should be individualized and should be done under close supervision of an Allergist/Immunologist

Blog post based on Med-Peds Forum talk by Ashley Nguyen, PGY2