What should you know about urticaria due to cold and heat?

Cold urticaria may produce itchy welts where cold air, water, objects or a sudden temperature change touches the skin. Heat-related hives may follow overheating, sweating, hot water or exertion. Some people notice symptoms as the skin warms after cold exposure, so the timing is worth recording.

Hives can be raised, itchy and transient, but temperature reactions can affect more than the visible skin. Deeper swelling is called angioedema. A clinician may use the exposure history and, when appropriate, supervised testing to clarify the pattern.

Protect skin from abrupt temperature changes. Use lukewarm water, layer clothing in cold weather, avoid prolonged cold-water exposure and cool down gradually after exercise. In hot conditions, seek shade, drink fluids and choose breathable clothing. Do not deliberately test a suspected trigger alone.

Keep a record of the exposure, delay before symptoms, affected areas and any swelling. An oral antihistamine may help some people when recommended by a clinician or pharmacist. Ask for an individual plan if cold water, heat or exertion has caused widespread symptoms.

Seek emergency help for throat, tongue or facial swelling, trouble breathing, wheezing, dizziness, faintness or difficulty swallowing after cold or heat exposure. A whole-body reaction can progress quickly, especially after cold-water immersion.

Arrange an appointment if episodes recur, spread beyond the exposed area, disturb sleep or occur without a clear temperature trigger. A clinician can check for other causes and discuss prevention and treatment options.

Ask whether the pattern fits cold or heat urticaria, which exposures to avoid, whether an antihistamine is suitable, and what to do during travel, swimming or exercise. Ask exactly which swelling or breathing symptoms require emergency action.