An acute allergic reaction to either a ingested or inhaled antigen charcterized by occurrence of transient, itchy, erythematous, raised patches of varying sizes and shapes. It’s a very common problem that can persist for long time, with proper treatment patients do well.

Urticaria occurs because of release of some mediators like histamine and serotinin in the body from immune cells resulting in a state of dilatation of blood vessels and increased leakiness of vessels resulting in collection of fluid in the skin; as this fluid gets reabsorbed the lesions disappear. The trigger for release of these mediators can be allergic or even non-allergic. Traditionally it was always considered that the main cause of urticaria was an immediate hypersensitivity reaction to an allergen that entered our body by way of ingested food or medications, inhaled pollen & dust etc or injected allergen like medications or insect bites. But now it is understood that very few of the urticaria are actually caused by a hypersensitivity reaction. In many of cases of urticaria the trigger cannot be identified.

Sometimes urticaria can be associated with life threatening situration where because of laryngeal edema patients might suffer from choking sensation and if not treated urgently with appropriate medication it can result in death. So anytime there is a choking or breathing difficulty associated with urticaria it is very important to rush to a nearby hospital immediately. These situation are handled by injection of adrenaline.