Learning about urticaria hives
Urticaria hives can emerge at any part of skin; they constitute lesions with a diameter of five or ten millimeters, the lesions can be enhanced, erythematous or with a reddish zone, with irregular borders, they are migratory, and with an intense pruritus and itching on skin. From the etiopathogenic point of view we can mainly distinguish three varieties of urticaria:
- Allergic or immunological urticaria, which corresponds to a variety that involves mechanisms of hypersensibility of the type I.
- Another variety is the one produced by cold, water, heat and pressure
- A last group is corresponds to idiopathic urticaria for which an etiological explanation cannot be found.
Normally urticaria hives emerge when there is a triggering factor, usually an allergen (which produces an allergic reaction) and which makes the body to produce histamine. The histamine makes small blood vessels known as capillaries to lose liquid; the liquid is accumulated on the surface of the skin and triggers the emergence of an eruption.
Urticaria can be triggered by many factors, among them:
- An allergic reaction, for instance, to certain foods or bites of certain insects like bees and wasps. An allergic reaction can also take place if the skin enters in contact with something irritating like latex and chemical products.
- Medicines can also trigger a reaction on skin like nonsteroidal antiinflammatory (NSAIDs) which are employed to treat pain and fever, and the medicines that are used to treat high blood pressure.
- Physical triggers like pressure over skin, low temperature, sunlight and water. However on fifty percent of the cases the cause of urticaria cannot be identified.
Urticaria is a frequent disease which affects to one of each six persons at any time of life. The eruption normally disappears after just a few days, but in some cases they can last for more time. It is not contagious. A type of urticaria which does not continues for more than six weeks is known as acute urticaria.
If the episodes of urticaria last more than six weeks the condition is known as chronic urticaria. This type of urticaria is much rarer than acute urticaria; it usually affects one among each one thousand persons. The causes for chronic urticaria on most of the cases are unknown, but there is the belief that this is a problem with the immune system of the person. The inflammation associated to chronic urticaria produces a burning sensation.
Around fifty percent of the people with chronic urticaria and around twenty five percent of the people affected with acute urticaria also get to be affected by a condition known as angioedema. The angioedema consists in the inflammation of deeper layers of skin; it is manifested as edematous plaques of infiltrated touch with a bigger size than the size of urticaria hives. The most frequent places where angioedema can be found are eyelids, lips, throat, and genitals settling in matter of hours and taking more than two days to disappear.