What should you know about sun exposure hives?

Hives can be pink, red or skin-coloured, with raised borders and intense itch. Individual welts may fade while new ones appear, and exposed areas are often affected first. Some people also develop deeper swelling, called angioedema, around the lips, eyelids, hands or throat. A rash after sun exposure can have other causes, including sunburn, contact reactions or medication sensitivity, so timing and appearance are useful clues.

Move out of direct light, cover exposed skin and use a cool compress. Avoid scratching and note the light exposure, medicines, products and foods around the episode. A clinician or pharmacist may recommend an oral antihistamine when appropriate. Recurrent reactions need a plan for protection and evaluation; do not start oral corticosteroids without medical guidance.

Call emergency services immediately for trouble breathing, throat or tongue swelling, faintness, wheezing, confusion or rapidly worsening symptoms. Seek same-day medical advice for widespread hives, repeated episodes or swelling that does not settle. Emergency symptoms can reflect a serious allergic reaction and should not be judged by how small the skin rash looks.

Could this be solar urticaria or another light-related rash? Which antihistamine is suitable for me? Should I review any medicines, and how can I protect my skin while the cause is investigated?