Urticaria is commonly known as rash. It is a localized edema reaction caused by the expansion and permeability increase of small blood vessels in skin and mucosa, which generally subsides within 2 ~ 24 hours, but new rashes appear repeatedly. The course of the disease is delayed for several days to several months. It is more common in clinic.
The cause of urticaria is very complicated, and about 3/4 patients can't find the cause, especially chronic urticaria. Common reasons are: food and food additives; Inhalation; Infection; Drugs; Physical factors such as mechanical stimulation, cold and heat, sunlight, etc. Insect bites; Mental factors and endocrine changes; Genetic factors, etc.
therapeutic method
1. General therapy
Because the etiology of urticaria is different, the treatment effect is also different. Specific treatment measures are as follows:
To remove the cause, we should try to find the cause of the attack for each patient and avoid the attack. If it is caused by infection, the infected focus should be actively treated. Drug inducers should stop using allergic drugs; People who are allergic to food should not eat this kind of food after finding out the allergic food.
To avoid inducing factors such as cold urticaria, we should pay attention to keeping warm. Acetylcholine urticaria reduces exercise, sweating and mood swings, while contact urticaria reduces contact opportunities.
2. Drug therapy
Antihistamines
H receptor antagonist has strong antihistamine and other inflammatory mediators, and has good curative effect in treating various types of urticaria. Commonly used H 1 receptor antagonists include diphenhydramine, cyproheptadine, chlorpheniramine, Avastin, cetirizine, mizolastine, loratadine, ebastine, azelastine, desloratadine and so on. When monotherapy fails, two different types of H 1 receptor antagonists can be used together or in combination with H2 receptor antagonists. Commonly used H2 receptor antagonists include cimetidine, ranitidine and famotidine. It is effective for acute and chronic urticaria and cold urticaria. Dosage varies from person to person. Doxepin is a tricyclic antidepressant, especially for chronic urticaria, with few adverse reactions. Doxepin is a better choice for urticaria patients whose traditional antihistamines are ineffective.
Drugs for inhibiting degranulation of mast cells and reducing histamine release
Epinephrine sulfate m-hydroxyisobutyrate is a β2 adrenoceptor promoter, which can increase the concentration of cAMP in vivo, thus inhibiting mast cell degranulation. Ketothiol inhibits mast cell degranulation and prevents the release of inflammatory mediators (such as histamine and slow-acting substances). ) by increasing the concentration of cAMP in the body. Its repression. The preparation is stronger and faster than sodium cromoglycate, and can be taken orally. Sodium cromoglycate can block the combination of antigen and antibody and inhibit the release of inflammatory mediators. If combined with glucocorticoid, it can reduce the dosage of glucocorticoid and enhance the curative effect. Tranilast reduces histamine release by stabilizing mast cell membrane.
glucocorticoid
As a second-line drug for the treatment of urticaria, it should be given intravenously or orally when antihistamines are ineffective for severe acute urticaria's disease, urticaria vasculitis and stress urticaria, or when chronic urticaria is severely stimulated, so long-term application should be avoided.
Commonly used drugs are as follows: prednisone; Qu An Xilong; Dexamethasone; In case of emergency, intravenous drip of hydrocortisone, dexamethasone or methylprednisolone.
Immune inhibitor
Patients with chronic urticaria have autoimmune basis, and their condition is repeated. When the above treatment can not achieve satisfactory results, immunosuppressants can be used. Cyclosporine has a good effect. Azathioprine, cyclophosphamide, methotrexate and immunoglobulin can all be tried, and tripterygium wilfordii has a certain effect. Because of the high incidence of side effects of immunosuppressants, it is generally not recommended to treat urticaria.
In addition, drugs that reduce vascular permeability, such as vitamin C, vitamin P and calcium, are often used in combination with antihistamines. Diseases caused by infectious factors can be treated with appropriate antibiotics.