What should you know about large itchy welts?

Hives are raised, itchy areas that may appear suddenly and change shape or position. Individual welts can fade while new ones develop elsewhere. Triggers can include an infection, a medicine, food, heat, pressure, or contact with an irritant, although a trigger is not always found. Angioedema is deeper swelling that may affect the lips, eyelids, hands, feet, or throat and can occur alongside hives. A rash that stays fixed in one place, bruises, blisters, becomes painful, or leaves marks deserves a clinical assessment because it may not be ordinary hives.

Note when the welts began, where they appear, and any recent medicines, foods, illness, exercise, heat, or pressure on the skin. Keep the skin cool, wear loose clothing, and avoid scratching or suspected triggers. A pharmacist or clinician can advise whether an oral antihistamine is suitable for you; do not combine products or change doses without checking. If the swelling keeps returning, lasts beyond a short episode, or interferes with sleep, arrange a dermatology or primary-care review.

Call emergency services immediately for swelling of the tongue or throat, trouble breathing, wheezing, faintness, confusion, or difficulty swallowing. Seek prompt medical advice for rapidly worsening swelling, extensive skin involvement, fever, severe pain, purple or bruised-looking areas, or a new rash after a medicine. Skin swelling without breathing symptoms still warrants timely assessment when it affects the face or mouth.

Could this be hives, angioedema, or another rash? Which medicines or products should I avoid? Is an antihistamine appropriate for me, and what should I do if swelling reaches my lips or throat?