What are we allergic to?
It can be: foods, plants, latex, medications, dyes, insects,animals,bee stings, fibers, soaps,chemicals, you name it.
Cockroaches are a major source of allergen exposure in inner-city areas. Of the thousands of species, only a few are important sources of indoor allergens. The German and American cockroaches are the most commonly encountered (shown). Cockroach allergens are derived from saliva, feces, secretions, and dead bodies. The allergens are similar in size to house-dust mite allergens (roughly 10 μm), and remain airborne for short periods of time. An association between cockroach sensitization and asthma exacerbation has been described and may be a major source of morbidity for inner-city, low-socioeconomic patients. An image of an American cockroach is shown courtesy of Wikimedia Commons.
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.