The main symptom of urticaria is a red, raised, itchy rash.
The rash is made up of raised marks in the skin that are known as weals or hives. They are usually very itchy and range in size from a few millimetres to the size of a hand.
Individual weals normally fade after a few hours, but can be replaced by new ones elsewhere on the body. They may appear on just one part of the body or across a large part of it. The skin returns to normal as soon as the weal fades.
Pattern of symptoms
Most cases of urticaria are temporary (acute urticaria). The rash appears quickly, becomes most severe after 8–12 hours and then normally resolves within 24 hours (although it can occasionally persist for 48 hours).
Long-term urticaria
The pattern of symptoms in chronic hives can be unpredictable.
One small survey found that around half of people with chronic urticaria have outbreaks of symptoms that last for 6–12 weeks followed by times where their symptoms improve or go away all together (remission).
Certain triggers such as stress or alcohol can make symptoms worse. Read about the triggers of urticaria.
The same survey found that 1 in 10 people had persistent symptoms of urticaria that lasted all year round.
Symptoms of chronic urticaria are often most troublesome in the evening, which can make falling asleep difficult.
When to seek medical advice
You should visit your GP if your symptoms do not resolve within 48 hours.
Also contact your GP if you have severe symptoms that are causing distress and disrupting your daily activities. You may need a short course of steroid tablets (oral corticosteroids).
Read about treating hives.
Urticaria vasculitis
A less common form of urticaria is called urticaria vasculitis. This causes the blood vessels inside the skin to become inflamed.
In this form of the disease, the weals last longer than 24 hours, are more painful and can leave a bruise.
Urticaria vasculitis may require referral to a skin specialist (dermatologist).
