Epidemiology

  • #1 chronic inflammatory skin condition
  • 20-30% children; 2-10% adults
  • Urban> Rural
  • Developed> developing countries
  • + family history of AD = strong risk factor for AD (vs. asthma or allergic rhinitis)

3 types of onset

  1. Early-onset:
    • Starts < 2yo (<6mo – 45%, <1yo – 60%, 5yo -85%); most common type; 60% children in remission by 12yo
  2. Late-onset:
    • Starts after puberty, mainly women
  3. Senile-onset:
    • Rare, starts > 60yo

Triggers

  • Environment (very hot / very cold temperature, low humidity)
  • Irritants (rough fabrics, soap, detergents, etc.)
  • Infections (cutaneous or systemic)
  • Environmental allergies (moderate-severe AD; aeroallergens: dust mites, pollen, fungi, etc.)
  • Food allergies (10-30% with moderate-severe-refractory AD; allergens: egg > milk, tree nuts, peanuts, soy, wheat)