Atopic Dermatitis (AD) Overview : Best article

• Definition of AD : Chronic, relapsing inflammatory skin condition associated with atopy (genetic tendency to develop allergic diseases).
• Etiology: Combination of genetic, immune, and environmental factors leading to skin barrier dysfunction and hypersensitivity.

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Clinical Features of

General Symptoms

• Pruritus (Itching): Hallmark symptom, often severe.
• Eczema Lesions: Age-specific distribution and morphology.

Age-Specific Presentation

1. Infants (<2 years)
   • Lesion Sites: Cheeks, scalp, forehead, extensor surfaces of arms and legs.
   • Appearance: Erythematous papules, vesicles, oozing, and crusting.
2. Children (>2 years)
   • Lesion Sites: Flexural areas (elbows, knees), wrists, and ankles.
   • Appearance: Lichenification, dry scaly patches.
3. Adults
   • Lesion Sites: Hands, eyelids, neck, and flexures.
   • Appearance: Lichenified plaques, chronic dermatitis.

Additional Features

• Dry Skin (Xerosis): Common in all ages.
• Excoriations: Due to scratching.
• Infection Signs: Secondary bacterial infections (e.g., Staphylococcus aureus).

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Differential Diagnosis of Atopic Dermatitis

• Seborrheic Dermatitis:
  • Greasy, yellowish scales on scalp, face.
  • Typically not pruritic in infants.
• Contact Dermatitis:
  • Localized to the site of contact with irritants/allergens.
  • Positive history of exposure.
• Scabies:
  • Intense itching, especially at night.
  • Burrows and lesions in web spaces, wrists, axillae.
• Psoriasis:
  • Well-demarcated, silvery scales on extensor surfaces.
  • Rare in infants.
• Impetigo:
  • Honey-colored crusted lesions.
  • Often secondary to bacterial infection.
• Ichthyosis Vulgaris:
  • Dry, scaly skin with no pruritus.
  • Family history common.

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Treatment of Atopic Dermatitis

Non-Pharmacological

• Skin Care:
  • Use emollients liberally to hydrate skin.
  • Avoid soaps and irritants; use mild, fragrance-free cleansers.
• Environmental Modifications:
  • Maintain optimal humidity.
  • Minimize allergens (dust mites, pet dander).

Pharmacological

• Topical Corticosteroids:
  • Low to medium potency for acute flares.
  • Avoid long-term use on sensitive areas.
• Topical Calcineurin Inhibitors:
  • Tacrolimus, pimecrolimus for steroid-sparing.
• Antihistamines:
  • To control pruritus (especially sedating antihistamines for sleep).
• Antibiotics:
  • Oral or topical for secondary bacterial infections.
• Severe Cases:
  • Systemic therapies (e.g., cyclosporine, biologics like dupilumab).