Atopic Eczema
Summary
Atopic eczema (atopic dermatitis) is a chronic, relapsing inflammatory skin condition characterised by pruritus, dry skin, and eczematous lesions with age-dependent distribution. It affects 15-20% of children and 2-3% of adults, typically beginning in infancy. Atopic eczema is part of the "atopic triad" with asthma and allergic rhinitis. Management centres on regular emollients, topical corticosteroids for flares, and avoidance of triggers. Severe disease may require systemic therapy including dupilumab (anti-IL-4/IL-13) or JAK inhibitors.
Key Facts
- Prevalence: 15-20% children; 2-3% adults
- Age of Onset: 80% before age 5
- Atopic Triad: Eczema, asthma, allergic rhinitis
- Cornerstone of Treatment: Emollients (250-500g/week)
- Flares: Topical corticosteroids (potency-matched to site)
- Severe Disease: Dupilumab, JAK inhibitors (baricitinib, upadacitinib)
Clinical Pearls
"Emollients Are the Foundation": Even during flares, continue emollients. "Soak and seal" strategy.
"Treat the Itch": Breaking the itch-scratch cycle is key. The itch that rashes.
"Age Changes Distribution": Infants = face/extensors; Children = flexures; Adults = hands/face.
"Eczema Herpeticum is an Emergency": Widespread vesicles + fever = urgent aciclovir.
Why This Matters Clinically
Eczema profoundly impacts quality of life for patients and families (sleep disruption, social impact). Inadequate emollient use is the most common cause of treatment failure. New biologics offer hope for severe, refractory disease.
Incidence & Prevalence
| Measure | Value |
|---|---|
| Childhood Prevalence | 15-20% |
| Adult Prevalence | 2-3% |
| Trend | Increasing in developed countries |
Demographics
| Factor | Details |
|---|---|
| Age of Onset | 80% before age 5; 60% in first year |
| Sex | Slight female predominance |
| Geography | Higher in urban, developed countries |
Risk Factors
Genetic:
- Family history of atopy (strongest)
- Filaggrin gene mutations (FLG)
- Maternal history of eczema
Environmental:
- Urban environment
- Low birth weight
- Reduced microbial exposure ("hygiene hypothesis")
- Food allergens (in some)
Mechanism
Barrier Dysfunction:
- Filaggrin deficiency → impaired stratum corneum
- Increased transepidermal water loss
- Allergen/irritant penetration
Immune Dysregulation:
- Th2-predominant inflammation
- IL-4, IL-13, IL-31 (itch cytokine)
- TSLP from keratinocytes
Itch-Scratch Cycle:
- IL-31 drives pruritus
- Scratching damages barrier further
- Self-perpetuating inflammation
Classification
| Type | Features |
|---|---|
| Intrinsic | Normal IgE, no sensitisation (20-30%) |
| Extrinsic | Elevated IgE, allergen sensitisation (70-80%) |
Symptoms
Signs by Age
| Age | Distribution | Morphology |
|---|---|---|
| Infant | Face, scalp, extensors | Acute: erythema, vesicles, oozing |
| Child | Flexures | Subacute: excoriations |
| Adult | Hands, face, flexures | Chronic: lichenification |
Red Flags
[!CAUTION] Red Flags:
- Eczema herpeticum (vesicles, fever, malaise)
- Erythroderma
- Cellulitis
- Failure to thrive
Structured Approach
- Distribution pattern
- Morphology (acute/subacute/chronic)
- Signs of infection
- Evidence of atopy (allergic shiners, Dennie-Morgan folds)
Special Features
| Sign | Description |
|---|---|
| Dennie-Morgan Folds | Infraorbital creases |
| Allergic Shiners | Periorbital darkening |
| Lichenification | Thickened, leathery skin |
| Xerosis | Generalised dry skin |
- Usually clinical diagnosis
- Allergy testing: SPT/specific IgE if food allergy suspected
- Skin swab: If infection suspected
- Patch testing: If contact allergy suspected
See Management Algorithm above (Section 2)
Summary
| Severity | Treatment |
|---|---|
| All | Emollients + trigger avoidance |
| Mild | Mild topical steroid |
| Moderate | Moderate-potent steroid, TCI |
| Severe | Dupilumab, JAK inhibitors |
| Complication | Notes |
|---|---|
| Eczema Herpeticum | HSV dissemination — emergency |
| Bacterial Infection | S. aureus colonisation common |
| Skin Atrophy | From prolonged potent steroids |
| Sleep Disturbance | Major QoL impact |
| Growth Restriction | Rare, from severe disease |
Natural History
- 60% clear by adolescence
- 40% persist into adulthood
- Adult-onset eczema also occurs
Atopic March
- Eczema → Allergic rhinitis → Asthma
- Screen for respiratory symptoms
Key Guidelines
- NICE NG190: Atopic eczema in under 12s (2023)
- NICE CG57: Atopic eczema in adults (2007, updated)
- AAD Guidelines (2022-2023)
Landmark Trials
SOLO 1/2 (2016) — Dupilumab
- Phase 3 RCTs showing significant EASI improvement
- Established dupilumab as first biologic for AD
MEASURE UP 1/2 (2021) — Upadacitinib
- JAK inhibitor vs placebo
- Rapid, sustained responses
Evidence Strength
| Intervention | Level |
|---|---|
| Emollients | 1a |
| Topical steroids | 1a |
| Dupilumab | 1a |
| JAK inhibitors | 1a |
What is Eczema?
Eczema is a common skin condition that makes your skin dry, itchy, and inflamed. It's not contagious and often runs in families with asthma or hay fever.
Why does it matter?
- It can be very itchy and disrupt sleep
- Skin can become infected if scratched
- It affects quality of life
How is it treated?
- Moisturisers (emollients): Use lots, every day — the cornerstone of treatment
- Steroid creams: For flares — use as directed, not long-term on face
- Avoiding triggers: Soap, irritants, allergens
- Injection treatments: For severe eczema that doesn't respond to creams
When to seek help
- Skin becoming infected (oozing, crusting, painful)
- Clusters of blisters with fever (eczema herpeticum)
- Treatment not working
Primary Guidelines
- National Institute for Health and Care Excellence. Atopic eczema in under 12s: diagnosis and management (NG190). 2023. nice.org.uk/guidance/ng190
Key Studies
- Simpson EL, et al. Two Phase 3 Trials of Dupilumab versus Placebo in Atopic Dermatitis (SOLO 1 and SOLO 2). N Engl J Med. 2016;375(24):2335-2348. PMID: 27690741
Reviews
- Wollenberg A, et al. European guideline (EuroGuiDerm) on atopic eczema. J Eur Acad Dermatol Venereol. 2022. PMID: 35980214
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