Cholinergic Hives

Cholinergic urticaria more commonly known as heat hives is a sub class of physical urticaria or hives. Cholinergic hives are skin rashes that occur due to an oversensitive reaction to body heat. An outbreak of hives occurs when the body is triggered by stimuli such as exercise (exercise-induced hives), heat from the sun (solar hives), saunas, hot showers (water hives), spicy foods which causes an increase in body temperature. Cholinergic hives can even occur due to stress or anger. Some people get hives during the winter months where their body temperature rises when it is not acclimatized to heat.

Causes of Cholinergic Urticaria

When the brain notices an increase in the body temperature, it sends down a neuron chain which stimulates the sweat glands. The neurons then release a chemical called acetylcholine. This chemical causes the degranulation of mast cells in the skin. This in return leads an extensive release of histamine in the body. The release of histamine causes skin rashes and skin inflammation which is itchy, which are called hives. Researchers have not understood exactly as to what brings about the release of histamine when the body sweats. However it has been hypothesized that a hormonal imbalance, vitamin deficiency or allergies could be the reason for this. Cholinergic Urticaria can also be caused by an autoimmune disorder.

Symptoms of Cholinergic Urticaria

• Hives become visible within minutes of rise in body temperature but may take longer to become visible on the skin. Visible skin rash is often preceded by itching or burning sensation.
• A person with cholinergic hives may experience discomfort when the room or body's temperature increases. This is an indication that a hives reaction may loom up.
• The person with cholinergic hives will experience intense itching. Hives and itching associated with it can appear anywhere on the body, but it is commonly found on the face, scalp, arms and hands.
• A person with cholinergic hives may complain of a prickly or burning sensation on the affected areas of the skin. This sensation usually occurs simultaneously with itching.
• In cholinergic hives, affected areas of the skin appear red. They may appear in clusters or may appear scattered. The flushing of the skin is often warmer than other parts of the body. The patient will have a tendency to scratch the hives.
• Sometimes hives can appear as small as a point on the skin. These pin points are red in color and does not last that long.
• Cholinergic hives can also cause swelling and inflammation of the skin. This usually occurs when the person suffering from cholinergic hives, scratches vigorously.