Urticaria

Key facts

• Urticaria (hives) is a skin reaction producing raised, itchy, pale-red welts; individual weals usually fade within 24 hours, though new ones can keep appearing for days or weeks.
• Episodes that recur for six weeks or more are classified as chronic urticaria; triggers include foods, medicines, insect stings, viral infections, and pressure or temperature changes on the skin, though many chronic cases have no identifiable cause.
• First-line treatment is a non-sedating antihistamine such as fexofenadine or bilastine; sedating options like hydroxyzine or cyproheptadine suit nighttime use.
• Swelling of the throat or tongue, difficulty breathing, or a drop in blood pressure alongside hives is an emergency: seek help immediately.

What sets it off

Almost anything can act as a trigger: foods such as shellfish, nuts, and eggs, medicines, insect stings, viral infections, latex, extreme temperatures, and pressure on the skin. Heat and humidity are common aggravating factors, and some viral infections are worth ruling out early when hives appear suddenly and severely. In a good number of chronic cases, no trigger is ever identified despite thorough investigation.

Controlling the itch

First-line treatment centers on antihistamines. Non-sedating options such as fexofenadine and bilastine are generally preferred for daytime use since they don't cause drowsiness. Older antihistamines like hydroxyzine and cyproheptadine cause more sedation and are often used at night or when that effect is acceptable. A full overview of available options sits under allergy relief.

When to seek urgent help

Seek medical attention immediately if hives are accompanied by swelling of the throat or tongue, difficulty breathing, or a drop in blood pressure. These signs point to anaphylaxis, a medical emergency that needs immediate treatment, typically with adrenaline, in an emergency department.

This page is educational and does not replace advice from a doctor or pharmacist who knows your health history.