Subscribe Feed (RSS)Most of the time, we know when we have an allergic reaction to something. We usually start sniffling or develop a skin rash. But a lot of the time we develop symptoms which, unknown to us, are actually signs that we are allergic to something.
Some of these symptoms include joint pains, muscle pains, headaches, stomach aches, asthma and acne. Allergic symptoms may also not develop at once, occurring as long as two to seventy-two hours after exposure, making it difficult to link them with the substance you are hypersensitive to. In these cases you need to undergo an allergy skin test to identify just what you are allergic to.
When you have an allergy skin test, a small drop of the suspected allergen is placed on the skin then scratched with a sterile needle. If the skin reddens and swells, then the test is considered positive. The test is usually performed either on the forearm or the back. Positive results imply that the patient has IgE antibodies on specialized skin cells (called mast cells) that release histamines which cause the redness and itchiness associated with an allergic reaction.
These skin tests may not be suitable for all sufferers however, in which case blood tests to identify allergens are conducted. One of these blood tests is the Elisa/ACT, which checks for delayed hypersensitivity to all foods as well as additives, preservatives and chemicals (from pesticides, soaps and other sources); another is the Radioallergosorbent (RAST) test. A small amount of blood is taken from the sufferer and analyzed for the presence of IgE antibodies to specific allergens. These blood tests are seen by doctors as being not as effective as skin tests and are more expensive, but are also useful in identifying hidden allergens.
