Hives reaction: how to respond

Hives are a skin response in which chemical signals widen small blood vessels and make nearby tissue swell. The result is a raised welt, often pink, red, or similar in colour to the surrounding skin. Itching is common, and separate welts can join into larger patches. A reaction may follow a food, medicine, insect contact, infection, temperature change, exercise, or pressure, but a cause is not always found. Deeper swelling of the lips or eyelids may accompany hives and is known as angioedema.

Move away from a suspected contact trigger and rinse exposed skin with water if appropriate. Use a cool compress, keep nails short, and avoid rubbing the welts. Ask a pharmacist or clinician about an oral antihistamine that suits your age, medical history, and current medicines. Read the label carefully and avoid taking more than directed. Record when the reaction started, what you ate or took, and whether exercise, heat, or pressure came first. This information helps a clinician separate hives from other types of skin rash and decide whether further assessment is useful.

Treat breathing difficulty, throat or tongue swelling, wheezing, voice change, dizziness, faintness, or collapse as an emergency and call emergency services. Do not wait to see whether the welts disappear. Get prompt advice for widespread hives after a new medicine, repeated vomiting, severe abdominal symptoms, or rapidly increasing facial swelling. Medical review is also sensible when the rash is painful, leaves bruising, comes with fever, or does not behave like fleeting welts.

Ask what may have started the reaction, whether your symptoms suggest angioedema, which treatment is appropriate, and what plan to follow if the reaction returns. Ask how to distinguish a routine flare from an emergency.