Urticaria is a restrictive edematous reaction due to reactive dilatation and increased permeability of small blood vessels in the skin and mucous membranes, mainly manifested as red or pale itchy lesions with well-defined margins – wind clusters.
[The etiology of urticaria is complex and the exact cause cannot be found in most patients. Common etiologies such as:
1.Food
Fish, shrimp, crab and eggs are the most common, followed by certain meats and certain plant foods such as strawberries, cocoa, tomatoes or garlic and other condiments.
2.Drugs
Many drugs are prone to cause the body’s metabolic reactions leading to the disease, common are penicillin, serum preparations, various vaccines, dysentery, sulfonamide, etc.. Some drugs are histamine releasing substances, such as aspirin, morphine, codeine, quinine, hydrazinebendazole, etc.
3.Infection
Including viruses, bacteria, fungi, parasites, etc. The most common are viruses and Staphylococcus aureus, which cause upper sensation, followed by hepatitis virus. The relationship between chronic infectious lesions, such as sinusitis, tonsillitis and chronic otitis media, and the development of urticaria is not easy to determine simply, and can only be confirmed by treatment trials.
4.Physical factors
Such as cold, heat, sunlight, friction and pressure and other physical stimuli.
5.Animal and plant factors
Such as insect bites, nettle stimulation or inhalation of animal dander, feathers and pollen, etc.
6, mental factors
Such as mental stress can cause acetylcholine release.
7, visceral and systemic diseases
Such as rheumatic fever, rheumatoid arthritis, systemic lupus erythematosus, malignant tumor, infectious mononucleosis, metabolic disorders, endocrine disorders, etc., can be the cause of urticaria, especially chronic urticaria.
[Clinical manifestations] is a common disease, the incidence of about 15% to 20%. According to the course of the disease, it is divided into two categories: acute and chronic, the former can be cured within a short period of time; the latter is recurrent up to several months to several years.
(A) Acute urticaria
The onset of the disease is often acute, with sudden itching of the skin and the appearance of red bumps of varying sizes, round, oval or irregular in shape. They are isolated or scattered at the beginning, and gradually expand and fuse into patches. When the serous exudation from the microvasculature is rapid, it compresses the wall of the canal, and the pale skin becomes uneven and orange peel-like. Within a few hours, the edema decreases and the puffiness becomes erythematous and gradually disappears. The duration of the wind masses usually does not exceed 24 hours, but new wind masses occur one after another. In severe cases, anaphylactic shock-like symptoms such as panic, irritability, nausea, vomiting and even lowered blood pressure may be associated with the disease. Some of them may have abdominal pain due to gastrointestinal mucosal edema, which may resemble acute abdomen when it is severe, or diarrhea, which may occur with shortness of breath and mucousy stools. When the trachea and larynx mucosa are involved, respiratory distress and even asphyxia may occur. If accompanied by high fever, chills, rapid pulse and other symptoms of systemic toxicity, you should be especially alert to the possibility of serious infections such as sepsis.
(B) Chronic urticaria
The duration of the disease is more than 6 weeks, and the systemic symptoms are generally mild, with more and less wind masses, which occur repeatedly, often for several months or years.
(C) Special types of urticaria
1.Dermatographism (skin scarring)
Also known as artificial urticaria (factitiousurticaria). After scratching or scratching the skin with a blunt instrument, striated elevations occur along the scratches, accompanied by itching, and soon fade away. It can occur alone or in conjunction with urticaria.
2.Cold urticaria
There are two types of coldurticaria: one is familial, autosomal dominant, relatively rare, and develops shortly after birth or early in life, and recurs throughout life. The other type is acquired and is more common. After exposure to cold wind, cold water or cold objects, the exposed or exposed parts of the body produce wind or patchy edema. In severe cases, there may be hand numbness, lip numbness, chest tightness, palpitations, abdominal pain, diarrhea, syncope and even shock. Sometimes eating cold drinks can cause edema of the mouth and throat. Passive transfer test may be positive, which may be related to IgE. Ice may induce localized wind masses. Cold urticaria can be one of the symptoms of certain diseases, such as cold globulinemia, paroxysmal cold hemoglobinuria, cold fibrinogenemia, cold hemolysis, etc.
3, cholinergic urticaria (cholinergic urticaria)
Mostly seen in young people, due to exercise, heat, emotional stress, eating hot drinks or ethanol drinks to make the deep body temperature rise, prompting the action of acetylcholine on mast cells and occur. It is often found in the upper part of the trunk and upper extremities, and does not fuse with each other, and can subside within half an hour to one hour. Sometimes there is only severe itching without a rash. It is occasionally accompanied by systemic reactions to acetylcholine, such as salivation, headache, slow pulse, narrow pupils, and spasmodic abdominal pain, diarrhea, and croup. Dizziness may be severe enough to cause syncope. The course of the disease usually improves gradually after several years. 1:5000 acetylcholine for skin test or scratch test, can be injected at the site of the wind, around the appearance of small star-shaped wind clusters.
4, solar urticaria (solarurticaria)
Less common, caused by medium-wave and long-wave ultraviolet light or visible light. The most sensitive to ultraviolet light with a wavelength of about 300nm. Passive transfer test can be positive for those who are allergic to 285nm~320nm ultraviolet light. Itchy and prickly sensation occurs on the exposed skin, and sometimes can be triggered by sunlight through glass. In severe cases, there are systemic reactions such as chilliness, weakness, syncope, and crampy abdominal pain.
5.Pressure urticaria (pressureurticaria)
About 4~6 hours after the skin is pressured, local swelling occurs, involving the dermis and subcutaneous tissue, lasting 8~12 hours to subside. It is common on the bottom of the foot after walking and on the skin of the buttocks after pressure. The mechanism is unknown and may be similar to skin scratching.
6, angioedema (angioedema)
It is a kind of limited edema that occurs in the subcutaneous tissue or mucous membrane, and is divided into two kinds: acquired and hereditary, the latter being rare. Acquired angioedema is often associated with other genetic allergic diseases. It occurs mainly in areas with lax tissue, such as eyelids, lips, external genitalia, hands and feet. It is mostly solitary and occasionally occurs in more than two locations. The damage is a sudden, limited swelling involving subcutaneous tissue with indistinct borders. The skin color is normal or light red, and the surface is bright and elastic to the touch. The swelling may fade gradually in 1 to 3 days, or it may recur in the same area. If it occurs in the laryngeal mucosa, it may cause respiratory difficulty and even death by asphyxiation.
[Treatment] The basic principles are antihistamine, reduction of vascular permeability, and symptomatic treatment. Strive to achieve cause-specific treatment.
(A) Systemic treatment
1, acute urticaria can generally be used chlorpheniramine, cyproheptadine, ketotifen and other first-generation antihistamines; some antihistamines more sensitive to drowsiness, drivers, high-altitude workers, work and study require a high degree of concentration on the second generation of antihistamines, such as cetirizine hydrochloride, terfenadine, astemizole, loratadine, etc.. Usually two to three antihistamines are used in combination. Vitamin C and calcium can reduce vascular permeability and have synergistic effects with antihistamines. Antispasmodic drugs, such as prulbenecid, 654-2, atropine, etc., can be given for those with abdominal pain. In cases caused by sepsis or septicemia, antibiotics should be used immediately to control the infection and treat the infected lesions.
In severe cases with shock or laryngeal edema and respiratory distress, subcutaneous injection of 0.1% epinephrine 0.5m1, rapid oxygenation, intramuscular injection of 25mg~50mg of promethazine hydrochloride, and hydrocortisone 0.2g~0.3g, vitamin C2g in 500m of 15%~10% glucose solution should be administered intravenously. 15min later, repeat injection of epinephrine 0.5m1. In patients with cardiovascular disease, epinephrine should be used with caution. In bronchospasm, aminophylline 0,2g (added to 5%~10% glucose solution) can be injected slowly intravenously. For laryngeal edema, tracheotomy is generally not advocated because it responds very quickly to epinephrine, and tracheotomy cannot resolve the accompanying bronchospasm.
2, chronic urticaria should actively search for the cause, should not use glucocorticoids, generally antihistamines are the main. The time of administration should generally be adjusted according to the time of occurrence of the wind mass. For example, more in the morning, a slightly larger dose should be given before bedtime; if more at bedtime, a slightly larger dose should be given after dinner. After the wind cluster is controlled, the drug can be continued for more than a month, and the dose should be gradually reduced. When one antihistamine is ineffective, 2~3 kinds of combination and multiple antihistamines can be used alternately.
If H1 receptor antagonists alone do not work well for intractable urticaria, H2 receptor antagonists, such as ranitidine, can be used in combination. In addition to antihistamines, you can use lisinopril, aminophylline, chloroquine, and tretinoin orally as appropriate.
3, special types of urticaria often use both anti-5-hydroxytryptamine, anti-acetylcholine drugs. Such as hydroxyzine, dechlorothiazide, physical urticaria has a better effect, Cyproheptadine on cold urticaria effect is more prominent. Cholinergic urticaria optional 654-2, etc.
(B) Topical drugs
In summer, you can use anti-itch liquid, furnace glycolate lotion, zinc oxygen lotion, etc. In winter, you can choose emulsions with anti-oxidation effect, such as Benadryl cream.
(C) Chinese medicine treatment
Acupuncture treatment, degree buried thread and other methods.