Hives are ultimately a response of the body's immune system. They form along the skin and can last anywhere from an hour to over six weeks in time. Typically, hives appear as raised bumps or patches that are slightly red and can cause some level of itching, but you may also experience other sensations, such as stinging or burning. An outbreak can happen anywhere along your skin, yet you'll often see them forming on the face, ears and inside the mouth. With a case of the hives, the actual cause can be almost anything.
In certain occurrences of hives, the cause of the condition is unknown, especially when you're dealing with chronic forms of the allergic reaction. Only 20 percent of cases involving chronic hives, according to the Cleveland Clinic, find a direct correlation between a stimuli and their formation. When you suffer from chronic hives, an outbreak usually lasts upwards of six weeks or longer.
Of all the discernible causes of hives, food products are probably the most common allergens. Nuts are one of the main culprits of this type of allergic response, but you may also find allergies that cause hives from things like eggs, dairy, berries, gluten, tomatoes, fish (as well as shellfish) or even chocolate. For some people, hives will form from the intake of food preservatives.
Another fairly common cause of hives is medication. Nonsteroidal anti-inflammatory drugs (NSAIDs), like ibuprofen or naproxen, top the list of medications that trigger an allergic response, but you can also get the hives from pain relievers, such as aspirin, as wells as from ACE-inhibitors and codeine. Of course, almost any medication can cause the hives; it just depends on the person's immune system whether or not you'll suffer this complication.
It is also possible to suffer from hives as a result of an insect bite. When a bug bites or stings you anywhere along the skin, the body may react with the formation of hives. But the response is usually delayed, anywhere from a few minutes to a few hours after the bite has occurred.
Surprisingly, your climate can even cause you to suffer from hives. In this situation, it's typically a sudden change in your environment that will cause this type of allergic reaction. Things like extreme cold or heat as well as exposure to the sun can prompt an abnormal immune response.
Hives can also be caused by direct stimulus of the skin. When this is the case, things like pressure or vibration may cause your skin to break out in this fashion. The scratching or itching of your skin can trigger the development of hives. Even sweat produces hives for some people.