WHAT IS URTICARIA?
Urticaria is a vascular reaction of the skin affecting the dermis and epidermis layer of the skin characterized by weals(hives) or angioedema (swelling) or both and appears as well circumscribed raised areas of erythema and edema with much itching.
Urticaria may be acute (< 6 weeks duration, often gone within hours to days) or chronic (> 6 weeks duration, with daily or episodic weals).
Urticaria usually occurs following an infection or as a result of an allergic reaction to any medicine, insect bite, food. Other triggering factors for urticaria include stress, cold temperature, hay fever, asthma, heat, perspiration, scratching etc. Sometimes there is no noticeable triggering factor seen.
SYMPTOMS & CAUSES
- Weals are due to release of chemical mediators which activate sensory nerves and leakage of fluid in surrounding tissues. Allergy IgE mediated also causes urticaria.
- Cause for various kind of urticaria depends on the type of urticaria. For example:- Certain medicines like aspirin, ibuprofen, penicillin etc may cause allergic reaction in the body and may induce urticaria.
Certain food items like sea food, certain dry fruits, nuts, eggs, cereals may also trigger urticaria.
- Scratching and striking on skin may also trigger urticaria in individuals affected with dermatographism. Some may have urticaria after slapping also.
- Some may develop urticaria after sustained pressure on certain areas where there is pressure for long time. For example at the waist line.
- Cholinergic urticaria may be seen during sweating, exercise, hot environment, emotional stress.
- When the skin is exposed to extremes of cold temperature then also urticaria may be seen.
- Solar urticaria is seen in exposed parts of the body on exposure to sun.