Atopic Dermatitis (Eczema): Causes, Symptoms & Comprehensive Management

Atopic dermatitis (AD) is a chronic, relapsing, Th2-driven inflammatory skin disease affecting 15–20% of children and 5–10% of adults in developed countries. It represents the cutaneous manifestation of the "atopic march" and profoundly impairs quality of life.

Pathophysiology: The "Outside-In" & "Inside-Out" Model

• Barrier defect: FLG (filaggrin) loss-of-function mutations (present in 30–50% of moderate-severe AD) → impaired stratum corneum → increased TEWL and allergen penetration.
• Immune dysregulation: Th2/Th22/Th17 skewing → IL-4, IL-13, IL-31, IL-22, TSLP → inflammation, itch, further barrier damage.
• Microbiome dysbiosis: S. aureus dominance (loss of diversity) → superantigens and toxins → amplified inflammation.
• Neural sensitization: IL-31, NGF, PAR-2 → perpetuation of the itch-scratch cycle.

Clinical Presentation

• Pruritus (sine qua non)
• Morphology: Acute (vesicles, oozing), subacute (scaling), chronic (lichenification)
• Distribution: Age-dependent (infant: face/extensor; child: flexural; adult: hands/eyelids/flexural)
• Associated stigmata: Dennie-Morgan lines, keratosis pilaris, pityriasis alba, hyperlinear palms

Triggers (Highly Individualized)

• Environmental: Low humidity, heat, sweat, wool, fragrances, detergents, dust mite, pet dander, pollen, mold.
• Psychological: Stress (elevates cortisol → barrier disruption, immune shift).
• Dietary: Food allergy in ~30% of children (egg, milk, peanut, wheat, soy); rarely a primary driver in adults.
• Infections: S. aureus, HSV, molluscum.

Comprehensive Management Framework

1. Foundation: Skin Barrier Repair

• Moisturize 2–3×/day (ceramide-dominant, petrolatum-based).
• Gentle cleansing: lukewarm, brief, fragrance-free, non-foaming.
• Wet wrap therapy for acute flares.

2. Anti-Inflammatory Therapy (Stepwise)

Severity	First-Line	Second-Line / Add-On
Mild	Low-potency TCS (hydrocortisone 2.5%) or TCI (tacrolimus 0.03%, pimecrolimus)	Crisaborole (PDE4 inhibitor)
Moderate	Mid-potency TCS (triamcinolone 0.1%) or TCI	TCI maintenance, phototherapy
Severe	High-potency TCS (clobetasol) short-course → step down	Systemic: dupilumab, tralokinumab, JAK inhibitors, traditional immunosuppressants

3. Itch-Specific Interventions

• Sedating antihistamines (nighttime only—no anti-inflammatory effect).
• Gabapentin/pregabalin (neuropathic itch component).
• Nemolizumab (anti-IL-31RA)—emerging.

4. Infection Control

• Dilute bleach baths (2×/week) for recurrent infection.
• Intranasal mupirocin (5 days/month) for S. aureus decolonization.
• Prompt treatment of impetigo, eczema herpeticum (emergency).

5. Lifestyle & Psychosocial

• Trigger avoidance (diary-guided).
• Stress management: CBT, mindfulness, biofeedback.
• Sleep hygiene.
• Diet: No routine elimination; allergist-guided only if IgE-mediated allergy confirmed.
• Support groups, mental health referral.

6. Monitoring & Follow-Up

• Validated scores: EASI, SCORAD, IGA, POEM, DLQI/CDLQI.
• Comorbidity screening: asthma, allergic rhinitis, food allergy, mental health.
• Growth (children), bone health (chronic TCS/systemics).

AD management is a marathon, not a sprint. A structured, individualized, multidisciplinary approach yields the best long-term control and quality of life.