Hives (urticaria) are raised, often pale-centred, itchy welts surrounded by redness or flushing that can appear anywhere on the body. A defining feature is that individual welts are usually short-lived, fading within minutes to hours and often reappearing elsewhere, so the rash seems to move around. They can be triggered by allergies, infections, heat, pressure, exercise or medications, and often no specific cause is found.
Most other rashes, such as eczema, psoriasis or viral rashes, tend to stay in the same spots for days and have a more consistent texture or scale. Hives blanch (fade) when pressed, which helps distinguish them from the non-blanching purple spots that can signal a serious infection.
Mild hives often respond to antihistamines, which a pharmacist can advise on. Seek emergency care if hives come with swelling of the lips, tongue, face or throat, wheezing, difficulty breathing or faintness, as this may be a severe allergic reaction. See a doctor if hives last more than six weeks or keep recurring. This is general information only.