Hives (urticaria) are red, itchy welts that result from a skin reaction. The welts vary in size and appear and fade repeatedly as the reaction runs its course.
The condition is considered chronic hives if the welts appear for more than six weeks and recur frequently over months or years. Often, the cause of chronic hives is not clear.
Chronic hives can be very uncomfortable and interfere with sleep and daily activities. For many people, antihistamines and anti-itch medications provide relief.