Atopic Dermatitis

1. Epidemiology
   1. Inherited sensitive skin (Atopic Patient)
   2. Incidence
      1. Affects 11% of children in U.S
      2. Affects 17.8 Million people in U.S.
      3. Most cases go undiagnosed
   3. Onset
      1. Typically presents with first 2 years of life (most often within first 6 months)
      2. Diagnosed in first 5 years in 90% of patients
      3. Many cases remit by age 3-5 years
2. Pathophysiology
   1. Disrupted Epidermis due to underlying filaggrin protein defect
   2. Allows for Dermis immune cell exposure to environmental antigens
      1. IgE Antibody response
      2. Increased T-helper 2 subtype activity
      3. Antigen-specific T-Cells secrete IgE binding factors
   3. Leads to inflammatory response
      1. Intense itching ensues due to a low itch threshold to provocative factors
      2. Scratching leads to further inflammation, resulting in a spiraling itch-scratch cycle
3. Types
   1. Acute Atopic Dermatitis
      1. Weeping, crusting lesions with overlying Vesicles
   2. Subacute Atopic Dermatitis
      1. Dry, Scaling, erythematous Papules and Plaques or
      2. Pityriasis alba
   3. Chronic Atopic Dermatitis
      1. Lichenification (e.g. Lichen Simplex Chronicus)
4. Associated Conditions: Atopic Triad (Family History)
   1. Eczematous Dermatitis (Atopic Dermatitis)
   2. Allergic Rhinitis
   3. Asthma
      1. Lifetime asthma Prevalence in patients with Atopic Dermatitis: 30%
5. 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
6. Symptoms: Pruritus
   1. Described as "The itch that rashes" (when scratched)
7. 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
8. 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
9. Diagnosis
   1. Pruritus (Required) and
   2. Additional Criteria (3 or more of the following)
      1. Asthma or Allergic Rhinitis history
      2. Flexor fold involvement
      3. Flexor fold dermatitis visible on exam
      4. Generalized Dry Skin
      5. Onset of rash before age 2 years
   3. Efficacy
      1. Test Sensitivity: 95%
      2. Test Specificity: 97%
   4. References
      1. Brenninkmeijer (2008) Br J Dermatol 158(4): 754-65
10. Differential Diagnosis: Varied Atopic Dermatitis presentations present a broad differential
    1. See Eczematous Skin Lesion
    2. See Pruritus
    3. Candidiasis
    4. Contact Dermatitis
    5. Dermatitis Herpetiformis
    6. Impetigo
    7. Nummular eczema
    8. Psoriasis
    9. Scabies
    10. Seborrheic Dermatitis
    11. Urticaria
    12. Xerosis
    13. Leung (2003) Lancet 361(9352): 151-60
11. Complications (associated with intense scratching)
    1. Secondary infection
       1. Impetigo
       2. Cellulitis
       3. Eczema herpeticum (Kaposi varicelliform eruption)
          1. Painful papulovesicular rash spread over localized skin region
          2. Skin infected by Herpes Simplex Virus infection
    2. Direct scratching complications
       1. Lichen Simplex Chronicus
       2. Prurigo nodularis
12. Management: Dermatology referral indications
    1. Diagnosis uncertain
    2. Pruritus and other symptoms refractory to treatment (especially if impacting sleep, school or work attendance)
    3. Facial Eczematous Dermatitis refractory to treatment
    4. Severe Atopic Dermatitis
    5. Frequent exacerbations of Eczematous Dermatitis
    6. Systemic medications required for maintenance or frequent exacerbations
    7. Allergic Contact Dermatitis (consider on face, Eyelids and hands)
13. 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
14. 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
15. 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 (see Eczema herpeticum under complications)
          1. Acyclovir
          2. Famciclovir
          3. Valacyclovir
    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. Ultraviolet Phototherapy
          1. Indicated in widespread refractory Atopic Dermatitis
       2. Accolate 20 mg PO bid
    4. Immunosuppressant (Topical and systemic agents)
       1. Calcineurin Inhibitors (topical)
          1. Highly effective agents
          2. Risk of skin malignancy or Lymphoma with prolonged use (FDA black box warning)
          3. Tacrolimus Ointment (Protopic)
             1. Tacrolimus 1% is approved for adults only, and is as effective as potent Topical Corticosteroids
             2. Tacrolimus 0.03% is approved for age 2 years old and older
          4. Pimecrolimus Cream (Elidel)
             1. Weaker, but may be better tolerated than the Tacrolimus Ointment
             2. Pimecrolimus 1% cream is approved for age 2 years and older
       2. Other agents
          1. Methotrexate
          2. Cyclosporine (Sandimmune)
          3. Azathioprine (Imuran)
16. References
    1. Kaplan (2001) CMEA Medicine Lecture, San Diego
    2. Berke (2012) Am Fam Physician 86(1): 35-42
    3. Burks (1998) J Pediatr 132(1): 132-6
    4. Drake (1995) Arch Dermatol 131:1403-8
    5. Krakowski (2008) Pediatrics 122(4): 812-24
    6. Reitamo (2000) Arch Dermatol 136:999-1006