Types of Hives
The term "hives" was coined within the medical community to refer to the wheals that appear on a person's skin as a result of a condition known as urticaria. Instances of urticaria are very common and can strike individuals of any age, race or gender at any time.
Hives usually appear as red lesions and can form in a matter of minutes or over the course of several hours. Hives occur when the capillaries dilate and allow fluid, usually containing histamines, to leak into the epidermis. The hives will not disappear until the body is able to reabsorb the liquid.
There are several different types of hives. The most common types of hives are as follows:
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Vibratory Angioedema
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Vibratory angiodema is the rarest form of hives. The stimulus that causes this particular form of hives is physical vibration such as that caused by operating a pneumatic tool, drying too vigorously with a towel or even jogging. The hives usually form within five minutes of exposure and disappear in under an hour.
Solar Urticaria
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Solar urticaria is another rare form of hives caused by exposure of usually covered areas of the body to the sun. These hives do not usually develop on parts of the body that are regularly exposed to the sun, like the hands or face, but form on other areas of the body such as the belly or back when they are exposed to the sun.
These hives will begin to develop almost immediately after the individual steps into the sun and will disappear within about an hour after exposure. A doctor can perform tests to determine what type of solar wavelength is causing the hives to form and will then choose the proper treatment. Treatments usually include antihistamines, sunscreen, exposure to build an immunity or complete sun avoidance.
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Dermographism
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Dermatographism is a form of hives caused when the skin is scratched or stroked with any type of object. Approximately 5 percent of people who suffer from hives develop this form, which usually presents itself when an individual scratches his skin or wears clothing that causes friction. The hives aren't round like most others but appear in straight lines and will usually disappear within an hour. Most people who develop dermatographism will have the condition for a few years and then outgrow it.
Cholinergic Urticaria
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Cholinergic urticaria is a form of hives that tends to develop after an individual exercises. These hives are usually very small, between two and three millimeters in diameter, and usually appear on the upper body. The hives are a result of the body temperature rising, which can be caused by exercise, stress and overheating in warm conditions. They usually appear anywhere between two minutes and an hour after the body temperature rises and will last for approximately 30 minutes.
Aquagenic Urticaria
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Aquagenic urticaria is a form of hives usually caused by contact with water. This is another rare condition and the hives will usually appear within 15 minutes after the skin touches the water. It is believed that this form of hives is not caused by the water itself but by a reaction to the chemicals within the water. The hives will last up to two hours before disappearing.
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