What causes heat rash?
Heat rash (prickly heat) occurs most often in hot, humid conditions, but you may develop it in cool weather if you’re overdressed. Excessive perspiration damages cells on the surface of the skin and this in turn forms a barrier and traps sweat beneath the skin, where it builds up, causing the characteristic bumps. You may, however, be thinking of Hives (otherwise known as Urticaria). These are red, itchy, raised areas of skin that appear in varying shapes and sizes. They range in size from a few millimeters to several inches in diameter. Hives can be round, or they can form rings or large patches. Wheals (welts), red lesions with a red “flare” at the borders, are one manifestation of hives, which can occur anywhere on the body, such as the trunk, arms, and legs. Some hives are caused by allergies to such things as foods and medications, but the large majority of cases are not allergic, and no specific cause for them is ever found. They usually resolve on their own over a period of week
