1, what kind of disease is allergic purpura?
Allergic purpura is a common allergic hemorrhagic disease caused by a variety of infectious agents or allergens involving the skin, joints, gastrointestinal tract, kidneys and other small blood vessels throughout the body. It is a kind of systemic vasculitis.
2, what factors can cause allergic purpura?
The cause of allergic purpura is complex and may be related to the allergic reaction caused by the following factors.
①Bacterial infection. ②Viral infection. ③ Parasitic infection. ④Food, such as fish, shrimp, crab, milk, egg, chicken, etc. ⑤Drugs, such as penicillin, sulfonamides, antipyretic and analgesic drugs, etc. ⑥Other such as cold, trauma, insect bite, pollen, vaccination, etc.
3.What is the incidence and clinical manifestation of allergic purpura?
The annual incidence of this disease is about 10 per 100,000. the average age of onset is 6 years. The incidence in males is about twice that in females. The incidence is more frequent in spring and autumn. Some patients have upper sensory symptoms 1-2 weeks before the onset of the disease. The four major clinical manifestations of allergic purpura are skin purpura, abdominal symptoms, joint symptoms and kidney involvement.
First, skin purpura. It is characterized by a hemorrhagic rash that appears in batches, varies in size, is symmetrically distributed, slightly above the skin surface, and does not fade when pressed. It is a good idea to have a good look. The initial color is bright red, mostly seen on the extremities, especially the extensor side of the lower extremities, some patients can spread to the buttocks, rarely appear in the trunk, especially the face, can be accompanied by mild itching.
Secondly, about 30% to 50% of patients have joint symptoms, which range from mild pain to significant mobility problems. Knee and ankle joints are the most common, presenting mainly periarticular lesions, which can recur without leaving joint deformities.
Thirdly, abdominal symptoms may appear in 50% of pediatric cases, and abdominal pain is the most common, characterized by mild abdominal pressure pain, abdominal muscle tension and rebound pain, although abdominal pain is severe. It may be accompanied by nausea, vomiting, diarrhea and black stools. Serious complications such as gastrointestinal hemorrhage, intussusception, intestinal obstruction and intestinal perforation are rare.
Fourth, kidney involvement. It is the most common complication of the disease, with an incidence of 30-60%, mostly seen within 2-8 weeks after rash onset. The most common manifestation is isolated hematuria. Proteinuria is mostly mild, but it can also develop into massive proteinuria and manifest as nephrotic syndrome.
4.How to diagnose and differential diagnosis of allergic purpura?
Purpura is a common but non-specific clinical sign, due to subcutaneous bleeding, which does not recede when pressed. There are many causes of purpura, which can be broadly divided into two categories: thrombocytopenic purpura and non-thrombocytopenic purpura. Allergic purpura belongs to the non-thrombocytopenic purpura and needs to be compared with simple purpura (also known as easy bruising or easy uveal mass syndrome), senile purpura, infectious purpura such as typhus and meningococcal infection, Waldorf hyperglobulinemic purpura, psychogenic purpura, prostrative purpura, pigmented purpura, self-inflicted purpura, and due to diffuse intravascular coagulation (DIC), even hypertension ( leading to stress purpura), scurvy (vitamin C deficiency, now rare), etc. Identify purpura and never consider it as allergic purpura once the platelet count is normal in purpura patients. The differentiation of thrombocytopenic purpura is mainly for platelet reduction.
5.How to prevent allergic purpura?
The preventive measures of allergic purpura include.
(1) prevention and treatment of various infections, avoid eating spicy, spicy, irritating food and seafood, do not eat food or drugs that can induce the disease, allergens unknown do not eat food that has not been eaten in the past, avoid cold.
(2) strengthen exercise, enhance physical fitness, cold season should pay more attention to prevent viral and bacterial infection.
6.How to treat allergic purpura?
The treatment of allergic purpura includes.
(1) actively search and remove the causative factors.
(2) symptomatic support treatment, such as abdominal pain can be used antispasmodic, gastrointestinal bleeding can be used cimetidine. Vitamin C can improve the fragility of blood vessels. Restricted diet should be used for heavy digestive symptoms.
(3) Anti-allergic therapy, urticaria or angioneurotic edema can be treated with antihistamines and calcium.
(4) Glucocorticoids. The indications are severe angioneurotic edema, severe abdominal pain with gastrointestinal bleeding, arthritis and severe renal lesions such as nephrotic syndrome and acute nephritis. Hormones can improve capillary permeability, reduce tissue edema such as intestinal edema, and prevent intussusception. However, it is not effective for cutaneous and renal types and cannot prevent the occurrence of nephritis, shorten the course of the disease and prevent recurrence.
(5) Anticoagulation therapy, such as heparin can reduce proteinuria. Thrombosis can choose urokinase and other thrombolytic drugs.
(6) immunosuppressants: for severe nephritis or complicated by membranous or proliferative nephritis, hormone alone is not effective, can be used in raglan, cyclophosphamide, azathioprine or cyclosporine A.
(7) Others, such as plasma exchange, high-dose intravenous gammaglobulin.
(8) Chinese medicine to tonify the kidney and benefit the qi, activate blood circulation and remove blood stasis.
7.When does allergic purpura nephritis appear?
Ninety-five percent of allergic purpura nephritis tends to appear 2 to 8 weeks after the appearance of purpura. A very small percentage of children may also have kidney involvement in 3 months to 6 months, and the longest may have kidney damage in several years. Those with pure hematuria with or without mild proteinuria. The prognosis is better. Large amounts of proteinuria. The prognosis is poor. Therefore, it is usually clinically necessary to test urine routine or urine sediment in children with purpura within six months.
8.What is the course and prognosis of allergic purpura?
The disease is a benign disease, most of the prognosis is good, about 10-20% of patients can relapse, less than 5% of patients develop chronic. The course of the disease is usually about 1~2 months, a few can be up to several months or more than a year. A few children with severe disease may die from intestinal bleeding, intussusception, intestinal necrosis, or acute renal failure. Renal lesions are often more prolonged and can last for months or years. Most of them resolve on their own. Factors that contribute to poor prognosis include: ① older age of onset; ② long duration of massive nephrotic proteinuria; ③ heavy renal biopsy pathology.
9. Vaccination of children with allergic purpura
For immune diseases, such as allergic purpura and nephrotic syndrome, vaccination is not advocated when the disease is unstable. Clinically, there are many cases of allergic purpura or aggravation caused by vaccination (rabies, measles, rubella, hepatitis A, influenza, hepatitis B, etc.), so when the disease is unstable or controlled for a short time, do not vaccinate as much as possible. Usually, vaccination is considered when purpura is stable for two months and immunosuppressive drugs are stopped.