What is the cause of Urticaria?
Acute urticaria is caused by drugs (pain killers such as aspirin, codeine, indomethacin and antibiotics such as penicillin & sulpha), specific food (nuts, eggs, fresh fruits, chocolates, fish, tomatoes, milk, spices, cheese, yeasts, food additives such as yellow dye) or a viral infection. In some cases, no cause can be detected.

Recurrent attacks of urticaria can occur by exposure to environmental agents such as sunlight, cold, pressure and sweat.

Chronic urticaria is defined as hives lasting longer than six weeks. It is rarely due to an allergy. Usually no cause is detected though; 30-40% of patients with chronic idiopathic urticaria will have an autoimmune cause.

What happens in Urticaria?
There is secretion of histamine and other substances from cells in the body leading to itching and enlargement of blood vessel in the skin leading to fluid extravasation and swellings.

Can Urticaria persist?
Acute urticaria resolves in few hours to days. Sometimes urticaria may occur daily and last more than two months. In majority of cases of chronic urticaria, the cause is not known. However, emotional stress is known to aggravate chronic urticaria. Most of the cases of chronic urticaria resolve by about 6 months.

Can skin tests be of use to find the precipitating cause?
Skin tests are generally of no use in Urticaria.