acute urticaria
Introduction
Introduction to acute urticaria Acute urticaria (AU) is a common clinical disease. It is an allergic skin disease characterized by itching, wheal or angioedema. It is a kind of skin and mucosal small blood vessel dilatation and permeability. Localized edema response. basic knowledge The proportion of illness: 0.3% Susceptible people: no special people Mode of infection: non-infectious Complications: diarrhea, shock
Cause
Acute urticaria cause
1. Food, animal and plant factors.
2, drugs, such as penicillin, sulfonamides, trimethoprim, serum vaccines, etc., often trigger urticaria through immune mechanisms. Aspirin, morphine, atropine, vitamin B1 and other drugs are histamine emissions, which can directly cause histamine to release urticaria from mast cells.
3. Infections, including viruses (such as hepatitis viruses), bacteria (such as Staphylococcus aureus), fungi, and parasites (such as aphids).
4, physical factors, such as temperature changes, daylight, friction, pressure, exercise, etc. can be caused.
5. Certain autoimmune diseases, gastrointestinal diseases, metabolic disorders, endocrine disorders and mental factors can also be caused.
Prevention
Acute urticaria prevention
1. Patients should pay attention to observing allergens. If they find themselves allergic to certain foods or drugs, they should be stopped immediately; try to avoid contact with suspected allergens.
2, cut short nails, do not forcefully scratch, otherwise it can cause significant increase in skin lesions, itching severe.
3, keep the stool smooth, constipation can take fruit guide 2 pieces, 2-3 times a day, An spleen leaves the right amount of boiling water.
4, indoors should be kept clean, dry, banned flowers, should not be sprayed with chemicals such as sue, dichlorvos, etc., to avoid sensitization.
5. Drivers and high-altitude workers are prohibited from taking anti-allergic drugs such as chlorpheniramine, diphenhydramine, and Antale during work to avoid accidents caused by symptoms such as dizziness and drowsiness.
Complication
Acute urticaria complications Complications, diarrhea, shock
Urticaria-like vasculitis, accompanied by vomiting, diarrhea, abdominal pain and other symptoms, severe can cause shock, left heart failure, double upper limb pain and other symptoms, severe cases can cause laryngeal edema and suffocation and life-threatening.
Symptom
Acute urticaria symptoms Common symptoms Windy itching skin redness skin indentation
Acute urticaria, often an acute attack, has itching throughout the body, and there are whistles of different sizes. The wheal can be fused into a large piece of skin lesions or damaged as a map. Acute patients often have red edema fragments, and some acute skin lesions may have blisters and bullae, called bullous urticaria. Some central areas may have purple spots, called purple spotted urticaria. The mucous membranes can also be affected, the lips are swollen, or the pharyngeal isthmus is swollen and the throat is swollen, causing difficulty in breathing and even suffocation. Skin lesions often resolve within a few hours, but one after another, new damage continues to occur, and severe large-scale hemorrhagic skin lesions can also resolve within a few days.
The whole body may have fever, generally within 39 ° C, such as above 39 ° C, should pay attention to the patient with or without acute suppurative infection, or sepsis. Respiratory symptoms can have asthma and difficulty breathing. The intestines may have abdominal pain or stomach cramps. Some can also have diarrhea. Patients with severe systemic wheal can also have symptoms such as decreased blood pressure, dizziness, chest tightness, etc., and very few can also have shock response. Treatment should be given promptly. Most patients have only whealing symptoms and no other symptoms. The course of the disease usually heals naturally within 1 to 2 weeks.
Examine
Acute urticaria examination
According to the repeated appearance of the skin, the rapid wheal, itching, leaving no traces, and the characteristics of various types of urticaria are easy to diagnose, but should be identified in the following diseases, if necessary, laboratory tests (including chest X-ray) Check abdominal B ultrasound, etc.) and related tests (such as exercise, hot water, sunlight, ice), allergen testing, etc. to further clarify the cause.
The following laboratory tests can be performed if the clinical symptoms are difficult to diagnose or if the cause is further sought.
1, suspected of rheumatism caused by urticaria can check erythrocyte sedimentation rate, anti-nuclear antibodies, serum complement determination, skin biopsy for the diagnosis of urticaria caused by complement activation.
2, for cold urticaria should check the syphilis serum test, determination of cold globulin, cold fibrinogen, cold hemolysin and ice test, anti-nuclear antibodies and other tests.
3, solar urticaria should check feces, urinary porphyrins, etc., should pay attention to the difference with SLE.
4, suspected to be related to infection, or a history of hepatitis in the liver or medical history at the time of physical examination, feasible blood routine, hepatitis B antigen, antibody test, stool eggs, fungi, X-ray examination of the lesions.
5, if suspected of thyroid disease should be used for anti-microsomal thyroid antibody related tests.
6. If you suspect that you are allergic to inhalation or ingestion, you should take an allergen test. If it is positive, you can take desensitization treatment.
7, serum urticaria patients with fever and joint pain, should check the blood sedimentation, such as erythrocyte sedimentation normal has important diagnostic value.
8. In addition to the obvious low-complementemia in the onset of urticaria vasculitis, the subunit Cla of serum Cl is significantly decreased, C4, C2 and Cg are moderately to severely reduced, and circulating immune complexes and low molecular weight Clq precipitates appear in serum. Direct immunofluorescence showed immunoglobulin and complement deposition in the skin wall of the skin.
9, autoimmune chronic urticaria can detect autoantibodies, using their own serum skin test: routine blood draw into a sterile tube for 30min, centrifugation, take serum 100l for the patient to perform an intradermal test, with saline as a control, such as 1h After the local appearance of the wind group diameter greater than 9mm is positive, other such as histamine release test, immunoblotting and enzyme-linked immunosorbent assay can be used.
Angioedema, especially hereditary angioedema, should be used for serum complement examination. It should be determined as the fourth component of complement (C4). If C4 is low, there may be a lack of complement first component esterase inhibitor (ClINH). Stage C4 is significantly lower than normal, and is lower than normal in the remission period. Even if there is no family history, the disease can be diagnosed. Conversely, if C4 is normal, the disease can be denied.
Chronic urticaria histopathology: simple local edema, serous exudation of the upper nipple and dermis, papilledema, a small amount of lymphocyte infiltration around the blood vessels, but infiltration can also be dense and mixed with eosinophils.
Diagnosis
Diagnosis and identification of acute urticaria
diagnosis
Urticaria is a wheal of skin lesions, which suddenly occurs, quickly resolves, and leaves no traces after disappearing. According to the characteristics of each type, it is not difficult to diagnose. It is difficult to find the cause. It is necessary to ask the medical history in detail and make a careful and detailed physical examination. It is very important to comprehensively analyze the disease and to find out the relevant factors of the disease in combination with various characteristics.
Angioedema can be resolved within a few hours to 2 to 3 days depending on the sudden occurrence of a large piece of temporary non-recessed swelling, often involving the eyelids, lips, tongue, external genitals, hands, feet, etc., the diagnosis of this disease is not difficult.
The diagnosis of hereditary angioedema can be based on medical history, positive family genetic history and serological examination. When the following clinical manifestations are available, the possibility of this disease should be suspected:
1. Recurrent episodes of localized edema.
2, there is self-limiting, generally 1 to 3 days can be resolved by themselves.
3, recurrent laryngeal edema or unexplained abdominal pain.
4, accompanied by emotions, menstruation, especially trauma and other incentives.
5, no itching and no urticaria.
6, the treatment with antihistamines and adrenocortical hormones is not effective.
7, a positive family history, nearly half of the family members of the disease.
8. Serum lipase inhibitory protein C4 and C3 values are reduced.
Differential diagnosis
Urticaria needs to be differentiated from papular urticaria and polymorphic erythema. Patients with abdominal pain and diarrhea should be distinguished from acute abdomen and gastroenteritis. Those with symptoms of high fever and poisoning should be considered as symptoms of severe infection. First, angioedema must be differentiated from substantial edema such as erysipelas, cellulitis and orbital contact dermatitis, adult scleredema, facial swollen malignant reticulosis, acquired angioedema and hereditary blood vessels. Sexual edema can be identified according to the above points.
First, the identification of infant eczema
Infant eczema refers to skin damage caused by eczema in infancy. Infant eczema can include atopic dermatitis in infants, but atopic dermatitis cannot equal or replace infant eczema, infant eczema includes infant contact dermatitis; seborrheic and rubbing Rotten infant eczema; atopic dermatitis in infants.
Second, the identification of angioedema
Angioedema is chronic, recurrent, large areas of local edema in the deep and subcutaneous tissues of the dermis. The etiology and pathogenesis are the same as those of urticaria, except that the plasma exudes from the interstitial space of small blood vessels in the deep or subcutaneous tissues of the dermis. Caused by loose tissue around.
Third, identification with gastroenteritis and some acute abdomen
Urticaria-like vasculitis wheal lasts for 24 to 72 hours, accompanied by fever, joint pain, increased erythrocyte sedimentation rate, hypocomplementemia, pathological examination for broken vasculitis, accompanied by vomiting, diarrhea, abdominal pain and other symptoms It should be differentiated from gastroenteritis and certain acute abdomen.
