Hives, a common name of Urticaria, is a kind of allergic skin disease with askin wheals as the main manifestation. The clinical manifestations are the appearance of wheals over the skin with sudden onset and rapid disappearance, leaving no trace after recovery.

There is a sensation of servere itching and burning heat on the affected part. Hives can attack repeatedly and last for a long time.

In Traditional Chinese Medicine, this disease is called "Yin zhen" (hidden eruption), "peilei" (urticaria), "fengzhen quai" (wind eruption), "you feng" (wandering wind evils). Typical symptoms are:

• The wheals appear all of a sudden. Most of them are red and oly few are pale. Their shapes very, but the borders clear. They may attack throughout the body or may be restricted to the face, neck or limbs. They may rise one after another and have frequent recurrences.
• Dermatographic test is positive. The wheal may be cause d by mechanical stimulation.
• The attack can be produced by exposure to cold, sunlight or due to psychic disturbance and intake of protein food, etc.

Hives is most often a sign of an allergic reaction. It is may be grouped as:

• Allergens - A large number of allergens have been identified as causative agents for some cases of hives.
• Food allergens - Milk, cheese, egg, protein products, wheat, cereals, fish, chicken, etc. Synthetic and natural food additives and artificially-flavored food articles.
• Environmental factors - Exposure to pollen, house-dust, buffalo dander, fungi, change in temperature, etc. are known exciting factors. Extreme cold, heat, pressure may also induce hives.
• Drugs - The major cause for urticaria are man-made drugs such as antibiotics (Penicillin), anti-inflammatory drugs (aspirin, indomethacin), vaccinations, foreign sera, hormonal preparations, contraceptive pills, etc. Animals treated with penicillin excrete a small amount of it in the milk sufficient to cause urticaria in sensitive individuals.
• Systemic and general disease - Urticaria in some cases may present as a sign of other systemic or general internal disease such as hormonal disorders (hyperthyroidism), SLE, polycythaemia, reticuloses, etc. In certain variety of malignancies (cancer) hives may present as a precursor.