What should you know about hives on body?

Hives may appear on the trunk, limbs, face, or several areas at once. Welts can be pale, pink, red, purple, or darker than surrounding skin, and they may merge into larger patches. Their tendency to change or disappear while new ones develop helps distinguish them from a fixed rash. Triggers include heat, pressure, exercise, infection, foods, and medicines, though an obvious cause is not always found. You may also notice [Skin Swelling](/symptoms/skin-swelling/) or intense [Itchy Skin](/symptoms/itchy-skin/).

Keep cool, avoid hot water and vigorous rubbing, and choose loose clothing. Write down everything that changed before the flare, including medicines, foods, products, illness, heat, and exertion. Take a photograph if the appearance changes quickly. Ask a pharmacist or clinician whether [Antihistamine Treatment](/treatments/medical-dermatology/oral-antihistamine-therapy/) is suitable. Repeated episodes, sleep disruption, or symptoms that do not settle warrant a clinical review.

Seek emergency help immediately if hives are accompanied by swelling in the mouth or throat, breathing difficulty, wheezing, faintness, confusion, or trouble swallowing. Deeper tissue swelling, called [Angioedema](/conditions/angioedema/), can be part of a serious reaction. Get prompt medical advice for painful or bruising lesions, fever, severe weakness, or a rash that remains fixed rather than shifting.

What pattern do my welts follow, and could an exposure or illness have triggered them? Which medicines are safe for me? If the flare returns, what symptoms should prompt emergency care?