Hives or urticaria is not really about what it is in the oatmeal or whatever other substance causes the rash, but more about what is in your body. Hives is usually caused by an allergic reaction, and in your case, you seem to have identified the trigger, otherwise known as an allergen. This is therefore an allergy related case of urticaria, and what you need to be focusing on is your allergy. An allergy is a kind of hypersensitivity to any particular substance, resulting in an excessive activation of the body's white blood cells, and subsequently some sort of inflammation. Basically, the body's immune system reacts to a harmless substance (such as oatmeal) as if it were a dangerous parasite. Allergies can cause a wide range of reactions, itching, swelling, diarrhea, nausea, cough, wheezing, nasal congestion, difficulty breathing, and, as in your case, hives. You will of course ask why the immune system reacts in this way - and while there is as yet no clear explanation, we do know that it is a mix of genetic and environmental factors. Among environmental factors, it is hypothesized that an environment that is too sterile can contribute to the development of allergies, because the immune system does not have enough real threats to keep it properly occupied. As a result, it overreacts to harmless substances. At the same time, excessive exposure to environmental pollution also seems to contribute to this malfunctioning of the body's immune system.
Whatever the case may be, your best option is to simply avoid oatmeal, whether as food or in any other form. Oatmeal is sometimes used in home remedies for urticaria, and this of course is something you should completely avoid. For allergens that are more pervasive and difficult to avoid, such as dust mites, or animal dander if you have pets, treatment is possible. Immunotherapy treatments modify the body's response to the allergen, and eventually cure the allergy completely. If you are interested in such treatments, you should consult an allergy specialist. However, for something such as oatmeal, this may not really be worth the time and money, unless you are really fond of oatmeal. Oats are certainly a very healthy food, and while there is no single substitute, you can get all the benefits of oats from a combination of other foods. The primary benefit of oats is its high content of soluble fiber, which is shared by legumes, barley, and many fruits.
answered by G R