If physical stimuli such as cold, heat, pressure, friction or light cause hives, one speaks of a physical urticaria or specifically of a cold, heat, pressure, etc. urticaria.
So you differ between following sub forms:
- Urticaria factitia
- Cold urticaria
- Heat urticaria
- Solar urticaria
- Pressure urticaria
- Vibration urticaria
In all sub-forms of physical urticaria, hives and itching and other urticaria complaints occur in response to a physical stimulus, for example cold or pressure. It is crucial that the physical urticaria occurs only after contact between the skin and the respective triggering physical stimulus and that urticaria occurs only in the irritated skin areas.
The word “factitia” comes from Latin and is derived from the word “facere”, which means “make”. Urticaria factitia is thus a “made urticaria”. Urticaria factitia is caused by rubbing, scratching, or scrubbing against the skin. This mainly affects young adults. Half of all persons affected by chronic urticaria show, at least temporarily, symptoms of urticaria factitia.
Here, the test is very simple: if a spatula or even just a fingernail is drawn across the skin with gentle pressure, swelling is observed in precisely the areas that had been subjected to pressure in this way. This phenomenon is also called dermographism, as it is possible to write on the skin in this way.
The main symptoms of urticaria factitia are volatile hives, redness, and itching. More rarely, tingling, biting, and heat sensation can occur. The skin lesions never occur spontaneously, but only in places where tight clothing has rubbed on the skin or where the patient has scratched. The strength of the forces necessary to trigger varies greatly. In the cases of some patients it takes only a light brushing, in other cases it requires heavy scratching to induce skin lesions.
After rubbing or scratching of the skin there is a reddening of the skin (due to increased blood flow) and later a reddened circle that goes far beyond the trigger point, at which a wheal then forms and itching occurs. At first, the wheal is still red. However, it then turns whitish and after a few minutes the clinical picture is complete: An itchy whitish wheal on a reddened circle extending slightly beyond the trigger points. After a short time the redness lessens somewhat. Then the itching becomes weaker and disappears with the wheal.
There are only very limited therapeutic options available. It is important to avoid the triggering stimuli. Avoid wearing tight-fitting, irritating, and chafing clothes and tight belts. In addition, it is worthwhile to give up certain medications such as antipyretic analgesics (aspirin, ibuprofen, diclofenac), penicillin, and codeine. Medicinally, urticaria factitia can usually be controlled well with antihistamines. The nightly itching represents the most significant limitation of the quality of life. Lightly sedating (tired-making) antihistamines taken before going to bed or antipruritic creams can help here.
Among the physical urticaria, cold urticaria, at about 15%, is not uncommon. In cold countries (Scandinavia) it is more common. Women are affected twice as often as men. Cold urticaria, however, is almost always chronic and lasts an average of five to seven years. In cases of cold urticaria, contact with cold objects or cold water or wind triggers the release of histamine at the location where the cold affects the skin. Within minutes, redness, swelling, and intense itching result. The course of the disease is individually very different; in some cases it is already triggered by changes in temperature—when the temperature goes from warm to cold—in others the outside temperature must drop below a determined value, and others already get the symptoms when they drink something cold or eat ice cream.
The skin symptoms are unpleasant but not dangerous. However, if large areas of skin are exposed to the cold stimulus, for example with a dip into cold water, large amounts of histamine are released. The consequences are increased heart rate, low blood pressure, shortness of breath and possibly a circulatory shock—in the worst case, in the form of anaphylactic shock.
Recently, so-called temptests have become possible. These are carried out with a special cold test device that is able to determine exactly, within the temperature range of zero to minus 45 degrees, the temperature at which cold urticaria is triggered in the patients.
Cold urticaria is often caused by infectious diseases. Sometimes other allergens or stimuli can cause the same symptoms, inter alia, food additives (e.g. colorant), drugs, plants, animal hair, sprayed fruits and vegetables, insect bites, pressure on the skin, physical exertion. These stimuli can, as you see, be very diverse, so the search for a triggering stimulus can be very difficult.
Since infectious diseases often occur together with cold urticaria, antibiotics may be generally helpful; a sufficiently high dose should be administered (possibly as an infusion). In addition, symptomatic antihistamines and leukotriene antagonists are used.
The so-called hardening therapy can be used as a drug-free treatment option. In the hardening treatment (cold desensitization), patients are exposed to repeated cold temperatures and baths; this is intended to cause them to get used to cold.
<p>For prevention, warm, tight, and skin-friendly clothing, including gloves, socks and warm shoes, are recommended. Uncovered areas of the face and other exposed body parts such as hands must be coated with a greasy cream. An emergency kit to protect the lives of patients from life-threatening swelling of the throat (caused by cold food and drinks) is available.
Heat urticaria is the counterpart to cold urticaria; however, it is extremely rare. The cause is unknown; there is probably an increased sensitivity of mast cells to heat. Triggers are hot objects or hot air. The critical temperature varies and is from 38 °C to 50 °C.
In general, the wheals and skin redness occur only where the skin has come into contact with a heat source. The symptoms usually remain only briefly.
The diagnosis can be made by means of a heat test. By contacting the forearm skin with a test tube filled with water at a temperature of 38-44 °C. Wheals occur after 5-10 minutes in the case of the immediate type, after hours in the case of the late type.
Avoidance of heat. The prophylactic, long-lasting, symptomatic therapy with modern antihistamines is usually successful. A drug-free treatment option, the so-called hardening therapy, can also be used here. In the hardening treatment, patients are repeatedly exposed to heat to achieve a habituation.
Light urticaria or solar urticaria is one of the more common physical urticaria. Popularly referred to as “sun allergy”. In the case of solar urticaria, the wheals and itching that are characteristic of urticaria are caused by light, especially sunlight.
Women are more often affected by solar urticaria than men.
Solar urticaria affects mostly young people around 30 years of age. But there are also cases in which much older persons develop this kind of urticaria. The average disease duration is about 4-6 years, but also disease durations of several decades are described in individual cases. One fifth of the patients suffering from solar urticaria simultaneously suffer from another form of urticaria, such as urticaria factitia or heat urticaria.
Seconds or minutes after exposure to UVA, UVB, or visible light, itchy hives are produced on the skin that was exposed to the light. Rarely, the hives do occur until hours after sun exposure. Skin that has been completely protected against light usually remains free of symptoms. However, light clothing often does not completely keep out UVA rays and visible light, so that it may happen that solar urticaria occurs also in “covered” parts of the body.
Using light tests, one can find out whether affected persons react only to a portion of the light spectrum, i.e., whether they are sensitive only to radiation within a specific wavelength range.
Approximately 60% of patients with light urticaria cannot tolerate visible light, about 30% respond only to invisible UVA radiation (340-400 nm wavelength), and an intolerance of UVB radiation (280-320 nm) is even more rare.
The diagnosis of solar urticaria is possible by means of accurate light testing. In this case, the skin is irradiated with light of different wavelengths to determine the wavelength range that causes urticaria. Testing is carried out with so-called “light stairs” on not normally sunlit skin, such as the back or buttocks. The cause or the exact mechanism by which urticaria attacks are caused by light irradiation in patients suffering from solar urticaria is still unclear. One can only try to prevent the outbreak of urticaria by protecting the sufferer against light or to alleviate the symptoms.
The simplest way is by means of sunscreens with a high SPF and broad-band filters. These are effective only in the case of sufferers who are reacting to ultraviolet light; they are of little help when urticaria is initiated by visible light.
Another option for treating the symptoms is the taking of antihistamines. This will usually achieve only an improvement of light tolerance. Very light-sensitive patients who react after a few seconds in the sun with urticaria benefit little from this therapy. Antihistamines inhibit only the itching and hives, but not the redness of the skin.
An alternative is a light-habituation treatment (hardening). Such treatment has few side effects, but it is expensive. In this therapy initially only parts of the body are irradiated with light at the individual urticaria-inducing wavelength or with UVA light (UVA-hardening); later the whole body is irradiated. In the case of some sufferers, this results in good sun tolerance already within a few days.
Four to eight hours after the sufferer is subjected to constant, vertically acting pressure, (delayed) pressure urticaria results, causing deep, often painful swelling that may persist for between eight and 48 hours. Clinically, pressure urticaria can be associated with fatigue, body aches, and slight temperature increase. As an isolated form, pressure urticaria, with a share of <1% of all urticaria, appears only rarely; usually it is associated with chronic urticaria, and it is often characterized by a long history.
Parts of the body subjected to pressure loads, such as the palms, soles, shoulders, and back, are predominantly affected. Men are affected twice as often as women. The peak age is 30 years. The duration until spontaneous remission is six to nine years.
Primarily, the diagnostic process comprises the pressure test, which is read immediately and with six hours delay.
Therapeutically, the distribution of weight over a larger area so as to reduce the pressure is recommended. Edges should therefore be avoided. Also, patients with foot discomfort can be helped by special sole inserts. High doses of antihistamines may improve symptoms.
Occurring in many places, vibratory urticaria or the localized vibratory angioedema occur during strong vibrations such as occur in connection with use of a jackhammer. The cause is usually clear.
This disease is rarely observed, since only a small part of the population is exposed to such strong vibrations.
Due to the clearly recognizable causative relationship, the avoidance of the causative factors is the treatment of choice in this case.