Heat welts on skin: what to know

Heat-related hives are raised, itchy areas that may be pink, red, or close to your usual skin tone. They can appear after a hot shower, exercise, fever, sun exposure, or a warm room. A single welt may fade while another appears elsewhere. The pattern is different from a burn, which is more likely to remain in the exposed area and may feel tender. Swelling deeper in the skin, especially around the lips or eyelids, is called angioedema and should be mentioned during assessment.

Cool the skin with a fan, a cool damp cloth, and loose breathable clothing. Avoid hot water, vigorous rubbing, and scratching. Record what happened before the outbreak, including exercise, foods, new products, medicines, and the length of each episode. A pharmacist or clinician may suggest an oral antihistamine, taking account of your age, pregnancy status, and other medicines. Do not apply steroid creams or take oral steroids without advice for an unexplained rash.

Get emergency help for difficulty breathing, throat tightness, tongue swelling, faintness, or rapidly spreading swelling. Seek a prompt appointment if welts keep returning, interfere with sleep, last unusually long, or become painful or bruise-like. A clinician may need to distinguish hives from contact irritation, infection, or another inflammatory skin condition.

What trigger pattern do my welts suggest? Is an antihistamine suitable for me? Should I avoid heat, exercise, or particular products for now? How can I tell ordinary hives from swelling that needs emergency help?