• Knowledge of specific sensitivities would improve care.
1. Guidance of environmental controls and avoidance measures
– Removing animals from home or reducing pet dander
– High-efficiency particulate air filters
– Dust mite controls: covers for bedding, removal of carpets/upholstery, washing bedding in high temperatures, acaricides
2. Guidance of medical therapy
– Use of appropriate allergy medications
– Subcutaneous immunotherapy
– Sublingual immunotherapy
CONTRAINDICATIONS FOR SKIN TESTING
• History of dermatographism
• Inability to discontinue antihistamine for testing
• Current use of beta blocker
• Previous episode of anaphylaxis
• Performed on volar surface of forearms, upper back, upper/outer aspects of arms, or anterior thighs
• Prick or prick-puncture testing developed to allow reproducible introduction of antigen into epidermis
• Less invasive, less discomfort when compared with intradermal testing
• Less likely to lead to systemic reaction than intradermal testing
• Useful when isolated testing of one antigen desired
• Place one drop of antigen concentrate per antigen (1:20 weight/volume) to be tested on skin, or dip test device into well of antigen.
• Pass single needle or lancet through antigen to create prick in skin, introducing antigen into epidermis without causing bleeding.
• In sensitized patient, IgE-induced wheal and flare will result.
Multiple-Allergen Prick Testing
• Several systems designed to test multiple antigens with one application
• Practitioner should consult individual test device packet insert for specific details regarding testing with that device.
• Device allows for equal distribution of pressure among needles
• Less variability among antigens, less technique-dependent influence on results
• Dip technique performed with antigen (1:20 weight/volume) in concentrate with 50% glycerin
• Positive control is histamine; negative control is 50% glycerin only.
• Antigens should be left on skin for at least 5 minutes, then blotted to avoid smearing.
Interpretation of Epicutaneous Testing
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