Dermatology Book

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Atopic DermatitisAka: Eczematous Dermatitis

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  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
    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. Tacrolimus Ointment (Protopic)
        1. Highly effective
        2. Consider as first line agent
      2. Methotrexate
      3. Cyclosporine (Sandimmune)
      4. Azathioprine (Imuran)
  13. References
    1. Burks (1998) J Pediatr 132(1):132
    2. Drake (1995) Arch Dermatol 131:1403
    3. Kaplan (2001) CMEA Medicine Lecture, San Diego
    4. Reitamo (2000) Arch Dermatol 136:999

Dermatitis, Atopic (C0011615)

Definition (MSH)A chronic inflammatory genetically determined disease of the skin marked by increased ability to form reagin (IgE), with increased susceptibility to allergic rhinitis and asthma, and hereditary disposition to a lowered threshold for pruritus. It is manifested by lichenification, excoriation, and crusting, mainly on the flexural surfaces of the elbow and knee. In infants it is known as infantile eczema.
Definition (CSP)chronic inflammatory skin disorder in individuals with a hereditary predisposition to a lowered threshold to pruritus; characterized by extreme itching, leading to scratching and rubbing that result in typical lesions of eczema.
ConceptsDisease or Syndrome (T047)
ICD9691.8
EnglishAllergic dermatitis, allergic eczema, ATOD, Atopic Dermatitides, Atopic Dermatitis, Atopic Eczema, Atopic Neurodermatitides, Atopic neurodermatitis, BESNIER PRURIGO, Besnier's prurigo, Canine atopy, DERMATITIS ALLERGIC, DERMATITIS ATOPIC, Disseminated Neurodermatitides, Disseminated Neurodermatitis, ECZEMA ATOPIC, Prurigo of Besnier
Spanishdermatitis alérgica, dermatitis alergica, dermatitis atópica, dermatitis atopica, eccema alérgico, eccema alergico, eccema atópico, eccema atopico, eczema alérgico, eczema alergico, eczema atópico, eczema atopico, neurodermatitis atópica, neurodermatitis atopica, neurodermatitis diseminada, prurigo de Besnier
CreditsDerived from the NIH UMLS (Unified Medical Language System)



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