What are we allergic to?
Sometimes you can develop an allergic reaction to something and never figure out the culprit unless you have testing done.
Identifying a culprit allergen can be very difficult, given the wide variety of compounds that humans are exposed to on a daily basis. A number of grid-based skin tests are available. In prick, or scratch, testing a purified allergen is intradermally injected to evaluate for a response. This method is commonly used for pet dander, dust, pollen, foods, and house-dust mites. In patch testing, allergens are kept in contact with the skin via hypoallergenic tape for an extended period of time to assess for a subsequent allergic inflammatory response. This method is commonly used for latex, medications, preservatives, and metals. Image courtesy of Wikimedia Commons.