Hives all over the body: what to know

Hives all over the body are raised, itchy welts that can appear and fade as the skin reacts to a trigger. Individual welts may change shape or location, while new ones form elsewhere. This pattern is also called urticaria.

Hives happen when skin cells release chemical signals that widen nearby blood vessels and cause fluid to move into the skin. Triggers can include an infection, a medicine, food, heat, pressure, or an immune reaction, and sometimes no single cause is found. Hives themselves are a condition; they do not by themselves identify a food or medicine allergy. Deeper swelling of the lips, eyelids, hands, or feet can occur alongside hives and is called angioedema.

Keep the skin cool with a gentle shower or a cool compress, wear loose clothing, and avoid scratching, vigorous rubbing, and any suspected new trigger. Take photographs if the welts move or disappear before an appointment, and write down recent foods, medicines, illness, heat, exercise, or pressure on the skin. A pharmacist or clinician can advise whether an oral antihistamine is suitable for you and how to use it. Do not start leftover steroids without medical advice.

Call emergency services immediately if hives occur with trouble breathing, wheezing, throat or tongue swelling, faintness, confusion, or repeated vomiting. These symptoms may signal a severe allergic reaction. Seek prompt medical assessment for rapidly increasing facial swelling, symptoms after a new medicine or sting, or a widespread eruption that is not settling. Arrange a dermatology or primary-care review when episodes keep returning, last beyond a short episode, or interfere with sleep.

Ask what pattern your skin shows, whether a medicine review is needed, which symptoms would change the urgency, and how long to continue any recommended treatment. Bring your photographs and a trigger diary.