Atopic%20dermatitis Diagnosis

• Diagnosis is based on patient's history, cutaneous findings (atopic stigmata), and physical exam
• Investigate exacerbating factors
  • Eg aeroallergens, foods, irritating chemicals, emotional stress, extreme temperature
• Identify and eliminate trigger factors
  • Identify potential allergens by careful history and selective allergy tests
    • Skin prick tests and serum tests for allergen-specific IgE are only useful if there is a suspected allergen
    • Negative results are useful for ruling out suspected allergens
    • In vitro allergy tests or positive skin prick tests do not always correlate with clinical symptoms (especially foods) and controlled food challenges, atopy patch tests or elimination diets may be needed
    • Limited food allergy testing may be considered in children <5 years with moderate-severe or refractory disease and/or a history of an allergic reaction after a particular food exposure 
      • Most children will outgrow food hypersensitivity within the first few years of life
    • Patch tests if contact dermatitis is suspected, eg palmar or facial dermatitis  

• Serum IgE levels may be considered to test for presence of an allergic disease
  • High serum total IgE level (≥500 IU/mL) may be indicative of atopic dermatitis
  • Specific serum IgE antibody tests and skin prick test may be used to identify specific sensitization
• Peripheral eosinophil count, serum lactate dehydrogenase (LDH) level and serum thymus and activation regulated chemokine (TARC) level may be used as markers for disease progression
  • An increase in LDH level may be indicative of tissue damage secondary to skin inflammation
• Though multiple mutations have been identified in the FLG gene, routine genetic diagnostic test for atopic dermatitis is not yet recommended

Criteria for Diagnosis (Based on criteria developed by Hanifin 1991)

Major Features (must have ≥3)

• Pruritus
• Typical morphology and distribution
• Facial and extensor involvement in infants and children
• Flexural lichenification and linearity in adults
• Dermatitis - chronic or chronically relapsing
• Personal or family history of atopy - asthma, allergic rhinitis, atopic dermatitis

Minor/Less Specific Features

• Cheilitis
• Hand/foot dermatitis
• Scalp (cradle cap) dermatitis
• Ichthyosis, hyperlinearity, keratosis pilaris
• IgE reactivity (increased serum IgE, radioallergosorbent, or prick test reactivity)
• Periauricular fissures
• Eczema
• Perifollicular accentuation
• Cutaneous infections (Staphylococcus aureus, Herpes simplex)
• Xerosis
• Recurrent conjunctivitis
• Keratoconus
• Anterior subcapsular cataract
• Ptyriasis alba
• White dermographism

Disease Severity

• Severity is assessed using different scoring methods [eg SCORing Atopic Dermatitis (SCORAD), Eczema Area and Severity Index (EASI), Patient Oriented Eczema Measure (POEM), Three Items Severity Score (TISS)] 
• SCORAD is the scoring method developed by the European Task Force of Atopic Dermatitis (ETFAD), which uses area/extent affected, intensity and subjective symptoms to score the severity of patient’s atopic dermatitis
  • Mild disease: <25
  • Moderate disease: 25-50
  • Severe disease: >50
• TISS is a simplified scoring system based on 3 symptoms of the disease: Erythema, edema/papulation, and excoriation
• POEM measures severity by depending on the patient’s answers to 7 questions based on symptoms and its frequency
• Pruritus severity is based on patient’s subjective assessment using the visual analogue scale (VAS) and the numeric rating scale (NRS) 
• Other scoring systems based on the impact on the quality of life are also used [eg Children’s Dermatology Life Quality Index (CDLQI), the Dermatitis Family Impact (DFI), Skindex-16, the Dermatology Life Quality Index (DLQI), and the Infant’s Dermatology Life Quality Index (IDQOL)]
• Ocular or infectious complications may also be present in severe atopic dermatitis
• May require hospitalization for severe eczema or skin infections