Individual hives can last any where from 30 minutes to 36 hours. While some hives disappear, new hives can show up.
About 40% of people who have chronic hives also got angioedema. Signs and symptoms of angioedema are large welts or swelling at the skin and may show up around the hands, feet, eyes and lips, genitalia, and even inside the throat. Swelling in the throat is able to stop breathing and requires emergency treatment. Angioedema can itch less than hives do, and can also cause pain or burning.
Symptoms might not show up all the time. They can come and go with no real trigger. For some people, some conditions — like heat, exertion or stress — can make the symptoms worse.
When to see a doctor
While chronic hives and angioedema usually are not life-threatening, they can be debilitating, and some times they are a sign of an underlying health problem.
See your doctor if you have:
Hives that won’t respond to treatment
Hives that keep appearing for several days
Seek emergency care if you:
Have trouble breathing
Think your throat is swelling