What should you know about cold and hot urticaria?

Cold urticaria may appear after cold air, water, objects, or a rapid change in temperature. Heat-related hives may follow warmth, exercise, sweating, hot showers, or emotional stress. Welts can be raised and itchy, and individual marks often change or fade while new ones appear. Swelling around the lips, eyelids, hands, or throat is called angioedema and needs particular attention.

The trigger is not always obvious. A clinician may ask what touched the skin, how quickly the reaction began, whether symptoms followed swimming or exertion, and whether medicines or infections were present.

Keep a record of temperature, activity, timing, and symptoms. Use gradual temperature changes, protective clothing in cold conditions, lukewarm bathing, and rest when warmth or exertion brings on welts. Avoid deliberately testing a strong cold or heat reaction, particularly in water. A clinician may recommend a non-drowsy antihistamine plan and explain whether further treatment is appropriate; do not change doses without advice.

Call emergency services immediately for trouble breathing, throat or tongue swelling, faintness, confusion, chest tightness, or rapidly spreading symptoms. Cold-water immersion can trigger a severe whole-body reaction in susceptible people. Seek prompt medical advice for repeated episodes, facial swelling, or hives that interfere with sleep or daily activities.

Ask which trigger pattern fits your symptoms, whether an antihistamine plan is suitable, how to handle swimming or exercise, and what emergency signs your household should recognise.