Do you know what causes heat hives (urticaria caused by increased skin temperature)?

 

Hives that are accompanied by red bumps or itching on the skin are classified into several types depending on what causes them. 'Heat urticaria', which I will introduce this time, is a non-allergic urticaria that is characterized by symptoms caused by heat stimulation such as a bath, heater, or hair dryer. This time, we will explain what kind of disease is heat urticaria, its symptoms, causes, and treatment.

What is heat hives?

What kind of disease do you mean by heat urticaria?

Heat urticaria is a skin disease in which the skin temperature rises by touching something warmer than body temperature, which is stimulated and causes hives. Hives are characterized by the appearance of a red, distinct 'wheap' on a part of the skin that disappears after a while, and there are several types depending on the cause.

It is broadly divided into two types: allergic and non-allergic. Heat urticaria is classified as non-allergic 'physical urticaria'. In addition, there is 'cholinergic urticaria', which shows symptoms similar to those of heat urticaria, so it is necessary to differentiate between the two sides.

non-allergic urticaria

'Type I (immediate type) allergy', which is well known as the cause of urticaria, causes urticaria to occur because the immune system overworks certain substances (allergens) such as shrimp or buckwheat noodles. Unlike this structure, heat urticaria is characterized by the development of urticaria without going through immune function (paraergic). Therefore, there is basically no such thing as heat hives from allergies.

physical urticaria

Among non-allergic urticaria, it is caused by external stimulation of the skin, such as scratching or pressure, cold, heat, sunlight, or contact with water. Physical urticaria includes, in addition to heat urticaria, mechanical urticaria, cold urticaria, solar urticaria, and water urticaria.

Differences from cholinergic urticaria

What is the difference between warm urticaria and cholinergic urticaria?

Cholinergic urticaria is urticaria that appears when taking a bath or exercising, and the symptoms are very similar to warm urticaria. However, cholinergic urticaria differs from thermal urticaria in that it occurs when sweating or a stimulus that induces sweating is applied. Heat urticaria is characterized by symptoms that occur regardless of sweating.

Symptoms of heat hives

It is characterized by a sudden appearance of a reddish-tinged wheal (swelling of the skin) on the part of the skin touched with something warm and disappearing after a while. The appearance of hives is often accompanied by 'itching', but in some people it is accompanied by a stinging pain or burning sensation.

The time and duration of the appearance of symptoms

Heat urticaria symptoms appear 'when' and 'how long' after being stimulated?

Symptoms such as skin redness and itching appear a few minutes after receiving heat stimulation, and disappear within a few minutes to 2 hours.

area where symptoms appear

Does heat urticaria have symptoms other than the area that has been stimulated by heat?

Most heat urticaria is 'local', and symptoms only appear in the area that has been stimulated by heat. However, some heat urticaria are 'systemic' in which symptoms appear even in places unrelated to the site of stimulation.

Causes of heat hives

What Causes Heat Hives?

The direct cause is an increase in skin temperature caused by thermal stimulation. In thermal urticaria, substances such as 'histamine' and 'prostaglandin' are released in large quantities from the mast cells of the dermis when the skin temperature is raised by thermal stimulation. When the histamine or prostaglandin acts on the skin, the blood vessels in the skin expand, making it easier for blood components to leak out of the blood vessels. This is what causes a reddish-tinged wheal on the skin. Moreover, because histamine stimulates the itch nerve, most hives are accompanied by itching.

Specific Factors That Cause Heat Hives

Some of the factors that cause heat hives in daily life include:

• Increased body temperature when bathing or sleeping
• Heating appliances (heaters, stoves, nose parts, hot carpets, etc.)
• Heating equipment (hot pack, hot eye patch, hot towel, etc.)
• hair dryer
• increase in skin temperature due to sunlight
• Warm air generated during cooking

Although there are individual differences in how much heat is a stimulus, it is known that there are many cases of onset by heat stimulation of 44°C or higher in the average data.

Heat urticaria examination subject

There are individual differences in the symptoms of heat urticaria, and mild symptoms may get better naturally. However, if urticaria symptoms appear frequently or if the symptoms are severe and interfere with daily life, consult a dermatologist near you.

Thermal Urticaria Test

Most of the hives can be diagnosed as 'hives' depending on the skin condition or the course of symptoms. Therefore, the examination focuses on determining what type of hives it is or finding the detailed cause. In confirmed physical urticaria, a test is performed to determine whether urticaria occurs by applying a stimulus that causes symptoms (mechanical stimulation, cold, heat, light, etc.). In the case of heat urticaria, it can be confirmed by a test called 'temperature induction', which applies a stimulus of 4 to 44°C to the skin.

Heat Hives Treatment

In thermal urticaria, the focus is first on preventing recurrence by designing to avoid, as far as possible, the thermal stimulus that is the source of urticaria in everyday life. However, if it is difficult to avoid it in daily life, such as using a hair dryer or heating device, or cooking, 'drug therapy' is implemented to suppress symptoms with drugs.

Heat Urticaria Medication Therapy

Most of the symptoms of urticaria appear when histamine produced by cells called 'mast cells' acts on blood vessels or nerves. Therefore, in heat urticaria drug therapy, 'antihistamine' that suppresses the action of histamine or 'antiallergic agent' with similar action is used. While these drugs are more effective than those for external use (applied drugs) internally or by injection, they have side effects such as drowsiness, so you need to be careful when using them. In addition to heat urticaria drug therapy, herbal medicines or drugs with the effect of modulating immune function are sometimes used.

Sex difference, age difference, etc. of heat urticaria

Although the sex and age difference of only warm urticaria is unknown, it is generally known that urticaria is more common in women in their 20s to 40s, and the sex difference is 1:2 in women.

organize

Thermal urticaria is a skin disease in which urticaria is caused by thermal stimulation that is higher than body temperature. When the skin temperature rises due to heat stimulation, a rash with red color and itching appears, which subsides in a few minutes to two hours. In treatment, we try to avoid heat stimulation that causes hives in our daily life, and we use antihistamines to relieve symptoms, such as drug therapy. Some heat hives get better spontaneously, but in case of 'repeating the symptoms of squatting' or 'the symptoms are painful', consult your nearest dermatologist.