Urticaria Causes

Urticaria causes

Various factors can create urticaria: circulating immune complexes (serum sickness, collagen, etc..), bacterial endotoxins, iodinated contrast materials used in radiology, cobra venom, specific enzyme deficiencies etc. The release of non-allergic mediators from target cells without any allergic phenomenon regards pharmacodynamic.

There are many products that can release histamine:drugs (aspirin, morphine, codeine, amphetamines, curare, colimycine, polymyxin B, dextran, thiamine, quinine molecules etc. ...), food (egg white, strawberries, pineapple, shellfish, chocolate, fish, alcohol, tomatoes), foods rich in histamine (fermented drinks, fermented cheeses such as Roquefort or Brie, fish, cabbage, canned tomatoes ...) or tyramine (Swiss cheese, smoked fish, sausages, game stale, tomatoes , cabbage, grapes, white wines ...).

Urticaria is also caused by non-specific factors like: alcohol, stress, emotions, physical exertion, premenstrual periods, etc.. Physical stimuli can also cause histamine release from target cells: heat, cold, sunlight, pressure, trauma, etc.. The causes of urticaria are numerous and there are two scenarios:

The crisis of urticaria, which often regresses spontaneously is most often allergic. There is sometimes a cause since the symptoms often appear a few minutes to several hours after it (taking a medication, unusual food, insect bites ...).
Chronic Urticaria can last 3 to 6 weeks so a detailed investigation is required. This investigation is very important one can discover the cause in 20 to 30% of cases.

Urticaria allergies causes

Allergies are rarely involved in this type of urticaria. They are more the cause of acute urticaria which extend a few hours to several days.
Some foods rich in histamine, such as chocolate, shellfish, tuna or strawberries for example, can aggravate chronic urticaria.
Medications: aspirin, non steroidal anti-inflammatory drugs, morphine and codeine may worsen urticaria.
The viral or bacterial infections and parasites may also be the cause.
Abnormal thyroid

The psychological dimension of hives should not be underestimated. The urticaria without cause found is called idiopathic urticaria and involves more than 60% to 70% of chronic urticaria. Physical urticaria may be the cause of chronic urticaria. The dermographisme is triggered by contact with skin and consists in small edge plates hives which appear at the point of friction.

A few urticaria pictures