Even though we call it a peanut, a peanut is actually a legume and belongs to the same family as lentils and peas. However, the proteins contained in the peanut are structured pretty much the same as other tree nuts. Hence, a peanut allergy can sometimes also imply allergy to other tree nuts, like walnuts, pistachios, almonds, pecans, hazelnuts, cashews, and macadamias.
This makes, peanut allergy one of the most common allergies and to a certain extent quite dangerous too because you might unknowingly consume peanuts through processed foods.
A peanut allergy occurs when your immune system perceives the peanut to be harmful and starts producing antibodies to fight the protein in the nut. The antibodies created are referred to as IgE (immunoglobulin E).
These antibodies can cause particular chemicals to be released into your body, one of them being histamine. Histamine, in particular, is a chemical that can influence your skin, respiratory system, cardiovascular system, as well as your gastrointestinal tract. These can result in prominent allergy symptoms like hives, vomiting, itching, wheezing and swelling.
There are only a couple of methods to test for peanut allergy. You can either do a blood test for peanut allergy or a skin prick test. Either way, peanut allergy tests can only indicate if you are allergic to peanuts or not. These tests cannot be relied upon to indicate the severity of an actual allergic reaction.
A peanut allergy blood test is also referred to as a RAST (radioallergeosorbent) test. This is accomplished with a sample of blood drawn from the vein in the arm. The sample collected is then tested to measure the IgE antibodies. A blood test helps you figure out if your body is sensitive to peanuts or not.
As the name suggests, if your doctor orders this test, your skin will be pricked and the pricked skin is then exposed to a small quantity of peanut proteins. Once exposed to the suspected allergen, your skin response is recorded to determine whether or not you are allergic.
In case of an allergy, you will notice a hive or a bump on the pricked spot on your skin. While this sounds simple enough, you should only let an expert or specialist perform this test and it definitely shouldn't be tried at home. While it is still inconclusive, some researchers do believe that the size of the hive can indicate if you have outgrown the allergy or not.
As mentioned above, these tests only prove that your body is generating a response to the peanut. Sometimes, these tests generate a false positive, that is, you test positive but you can still go ahead and enjoy peanuts without any allergic reactions.
You can always try a food challenge but this can be a long process and should only be done under medical supervision. Also, a food challenge is mostly useful when you're trying to eliminate probable causes for your allergic symptoms.