Atopic Dermatitis

1. Epidemiology
   1. Inherited sensitive skin (Atopic Patient)
   2. Incidence: 10% of children
   3. Onset in Infants often before age 6 months
      1. Often remits by age 3-5 years
   4. Low itch threshold to provocative factors
2. Pathophysiology
   1. IgE Antibody response
   2. Increased T-helper 2 subtype activity
   3. Antigen-specific T-Cells secrete IgE binding factors
3. Associated Conditions: Atopic Triad (Family History)
   1. Eczematous Dermatitis (Atopic Dermatitis)
   2. Allergic Rhinitis
   3. Asthma
4. Provocative Factors
   1. Sweating
   2. Bacterial colonization
   3. Rough clothing
   4. Chemical irritants
   5. Emotional Stress
   6. Foods
      1. Cow's milk
      2. Wheat
      3. Eggs
      4. Soy
      5. Peanut and tree nuts
      6. Fish
   7. Environment
      1. Dust or mold
      2. Cat dander
      3. Temperature changes
      4. Low humidity
5. Symptoms: Pruritus
   1. Described as "The itch that rashes" (when scratched)
6. Signs: Infants and young children
   1. Dermatitis characteristics
      1. Erythema and Edema
      2. Exudate
      3. Crusting
      4. Scaling
   2. Dermatitis Location
      1. Face (especially cheeks)
      2. Scalp
      3. Trunk
      4. Extensor surface of arms and legs
7. Signs: Older children and adults
   1. Dermatitis characteristics
      1. Similar eczematous skin changes as with infants
      2. "Hot and sweaty fossa and folds"
   2. Dermatitis Location
      1. Flexor wrists and ankles
      2. Antecubital fossa
      3. Popliteal fossa
      4. Hands
      5. Upper Eyelid Inflammation (erythema, fine scale and lichenification)
      6. Anogenital area
8. Differential Diagnosis
   1. See Eczematous Skin Lesion
   2. See Pruritus
9. Complications (associated with intense scratching)
   1. Secondary infection (Impetigo)
   2. Lichen Simplex Chronicus
   3. Prurigo nodularis
10. Management: General Measures
    1. See Dry Skin Management
    2. See Pruritus Management
    3. Chronic disease management
    4. Eliminate Environmental Allergens
    5. Infection Control
       1. Keep Fingernails short and clean
       2. Staphylococcus aureus colonization in 90% of eczema
       3. Treat superinfection (Impetigo) as needed
       4. Consider intranasal Bactroban to reduce seeding
    6. Feeding Changes (Very controversial)
       1. Common antigens related to Eczema
          1. Milk, Soy, Egg, Peanut, Wheat
       2. Uncertain whether diet changes improve eczema
       3. Consider eliminating for 1 month above antigens
          1. Consider starting with cow's milk elimination
          2. Consider Soy-based formula if persists
          3. Consider formal Allergy Testing
11. Management: Topical Steroid for exacerbation
    1. Consider alternative agents (e.g. Tacrolimus Ointment)
    2. General
       1. Limited use only for exacerbations
       2. Avoid Under-treatment
       3. Consider applying only at night
       4. Start early for exacerbations
       5. Treat all palpable areas
       6. Ointments are preferred
          1. Better tolerated (less burning)
          2. Allergic Reaction to ointment base less common
          3. Helps moisten very Dry Skin
    3. Mild exacerbation
       1. Use for 3-4 days only
       2. Low potency Topical Steroid (e.g. Hydrocortisone 1%)
    4. Moderate exacerbation
       1. Taper over 2 weeks
          1. Use twice daily for 7 days, then
          2. Use once daily for 7 days
       2. For Face and Groin
          1. Limit to Level 5 Topical Corticosteroid or less
          2. Hydrocortisone (0.5%, 1%, 2.5%)
       3. For Eyelid
          1. Tridesilon 0.05% or Aclovate 0.05% ointment or cream applied twice daily for 5-10 days
          2. Consider Tacrolimus 0.1% ointment or Pimecrolimus 1% cream for refractory cases
             1. Risk of malignancy with longterm use (see below)
       4. For body
          1. Hydrocortisone Valerate 0.2% (Westcort)
          2. Triamcinolone 0.1% (Kenalog)
    5. Severe exacerbation
       1. High Potency Topical Steroids (e.g. Fluticasone)
       2. Try to avoid Systemic Corticosteroids
       3. Consider maintenance Topical Steroid
          1. Low potency Topical Steroid daily or
          2. High potency steroid (eg. Fluticasone) twice weekly
             1. Berth-Jones (2003) BMJ 326:1367-70
    6. Other Anti-inflammatory agents
       1. Hydroxyquinolone
       2. Tar Preparations
12. Management: Refractory to above therapies
    1. Anti-infective agents
       1. Indication: Impetigo type superinfection
       2. Staphylococcus aureus coverage
          1. Augmentin
          2. Cephalexin (Keflex)
          3. Erythromycin
          4. Dicloxacillin
       3. Herpes Simplex Virus (HSV) coverage if suspected
          1. Acyclovir
    2. Systemic Corticosteroids
       1. Indicated
          1. Severe eczema exacerbations
          2. Refractory to high potency Topical Steroid
       2. Precautions
          1. Limit use to 1-2 weeks
          2. Works too well (Derails Topical Steroid treatment)
    3. Miscellaneous agents
       1. Accolate 20 mg PO bid
    4. Immunosuppressant (Topical and systemic agents)
       1. Calcineurin Inhibitors (topical)
          1. Tacrolimus Ointment (Protopic)
          2. Pimecrolimus Cream (Elidel)
          3. Highly effective
          4. Do not use for under age 2 years and avoid prolonged use (possible cancer risk) - FDA Black box warning
       2. Methotrexate
       3. Cyclosporine (Sandimmune)
       4. Azathioprine (Imuran)
13. References
    1. Burks (1998) J Pediatr 132(1): 132-6
    2. Drake (1995) Arch Dermatol 131:1403-8
    3. Kaplan (2001) CMEA Medicine Lecture, San Diego
    4. Reitamo (2000) Arch Dermatol 136:999-1006