1, what kind of disease is allergic purpura?
Allergic purpura is also known as allergic purpura, allergic purpura syndrome, Henoch-Holland’s purpura, Henoch-Holland’s syndrome, Henoch-Holland’s purpura, leukocyte destructive vasculitis, hemorrhagic capillary poisoning, rheumatic purpura, or AP, or HSP, or LV. AP 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 common allergic hemorrhagic disease involving the skin, joints, gastrointestinal tract, kidneys and other small blood vessels of the body caused by various infectious agents or allergens. It is the most common form of non-thrombocytopenic purpura in children. 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 allergic reactions caused by the following factors.
①Bacterial infections, commonly β-hemolytic streptococcal infections. ②Viral infections, influenza, rubella, chickenpox, mumps and hepatitis are the most common. ③ Parasitic infections, roundworm infection is the most common, followed by hookworm. ④Food, such as fish, shrimp, crab, milk, egg, chicken, etc. ⑤ drugs, such as antibiotics such as penicillin, sulfonamides, antipyretics and analgesics, and even insulin. 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 9 per 100,000. 90% are seen in children and adolescents, especially preschool and school-age children aged 2 to 8 years. The incidence is about twice as high in males as in females. The incidence is higher in the cold season. 50% of patients have a history of upper respiratory tract infection and fever 1 to 2 weeks before the onset of the disease. The four major clinical manifestations of allergic purpura are skin purpura, abdominal and joint symptoms and kidney involvement.
First, skin purpura. It is characterized by hemorrhagic rash, appearing in batches, varying in size, symmetrically distributed, slightly above the skin surface, and does not fade when pressed. It is mostly bleeding spots, and some of them can be fused to form patches. The rash is initially bright red in color and is usually seen on the extremities, especially on the extensor side of the lower extremities, and may spread to the buttocks in some patients, but rarely on the trunk and especially on the face. The rash may leave pigmentation after it subsides. In addition to purpura, it can also be complicated by urticaria and angioneurotic edema. Occasionally, purpura may also appear on the oral mucosa or conjunctiva.
Second, about 30% to 50% of patients develop joint symptoms, which range from mild pain to marked redness, swelling, pain and impaired movement. It often involves large joints, mostly knee and ankle joints, is wandering and transient, and is often misdiagnosed as “rheumatism”. It is mainly periarticular lesions, which can recur without leaving joint deformities.
Thirdly, 90% of children and 50% of adults can have abdominal symptoms, abdominal pain is the most common, mostly in the form of colic, obvious in the umbilicus and right lower abdomen, but also throughout the abdomen, characterized by severe abdominal pain, but light abdominal pressure pain, abdominal muscle tension and rebound pain is not obvious. It may be accompanied by nausea, vomiting, diarrhea and black stool. Serious complications such as gastrointestinal hemorrhage, intussusception, intestinal obstruction and intestinal perforation are rare and occur mostly in children. In the absence of skin purpura, it is often misdiagnosed as “acute abdomen”. It is a common cause of death in the acute phase.
Fourth, renal involvement. It is the most common complication of the disease, with an incidence of 30-60%, mostly within 4-8 weeks after rash onset, and rarely after several months. Individuals are seen before or up to 2 years after rash onset. The most common manifestation is isolated hematuria, with 1/4-1/2 cases reported in China as carnal hematuria. Proteinuria is mostly mild, but can develop into massive proteinuria and manifest as a nephrotic syndrome. In a few cases, acute renal failure may occur. Some patients may have hypertension and edema.
According to the above manifestations, allergic purpura can be divided into simple skin type, abdominal type, joint type and renal type, and if simple skin purpura is combined with other two or more types, it is called mixed type. In addition, the blood routine of this disease indicates normal or even increased platelets. The IgA and IgE in the blood may be elevated.
4. How to diagnose and differential diagnosis of allergic purpura?
Purpura is a common but non-specific clinical sign, due to subcutaneous bleeding, and does not recede when pressed. The diagnosis of allergic purpura should firstly clarify the difference between purpura, bleeding point and petechiae. Hemorrhagic spots, also known as petechiae, are less than 3mm in diameter, while petechiae are greater than 1cm in diameter, while purpura is between 3mm and 1cm in diameter. And then the purpura is identified, there are many causes of purpura, which can be broadly divided into two main categories: thrombocytopenic purpura and non-thrombocytopenic purpura. Allergic purpura belongs to non-thrombocytopenic purpura, especially the simple cutaneous type AP needs to be distinguished from simple purpura (PS, also known as prone to cyanosis or prone to 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) and other causes of purpura are identified and should never be considered as allergic purpura as soon as the platelet count is normal in purpura patients. The mixed type of AP is relatively easy to diagnose because there are few other diseases with simultaneous manifestations of skin, abdominal, joint or kidney involvement. And please refer to my article “Idiopathic thrombocytopenic purpura (ITP) Q&A” for the differentiation of thrombocytopenic purpura.
5. How to prevent allergic purpura?
Preventive measures for allergic purpura include.
(1) Prevention and treatment of various infections, diet should be light, avoid eating spicy, spicy, stimulating food and seafood, do not eat food or drugs that can trigger the disease, allergens unknown do not eat food that has not been eaten in the past, avoid cold.
(2) strengthen exercise, enhance physical fitness, in the 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. It is important to find and remove allergens, such as tonsillitis and other infectious lesions are cured, the disease is often relieved. There have been reports of persistent purpura being cured after hookworm exclusion.
(2) Symptomatic support treatment, such as abdominal pain can be used antispasmodic, gastrointestinal bleeding can be used cimetidine. Vitamin C is used to improve vascular fragility. Bed rest should be given during the acute phase. Heavy gastrointestinal symptoms should be restricted diet.
(3) Anti-allergic therapy, urticaria or angioneurotic edema can be used 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 pansentin to reduce proteinuria, and heparin. Thrombosis can choose thrombolytic drugs such as urokinase.
(6) Immunosuppressants: For severe nephritis or complicated by membranous or proliferative nephritis, if hormone alone is not effective, cyclophosphamide, azathioprine or cyclosporine A can be used.
(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.
Since the establishment of the department, the Department of Hematology of the First Affiliated Hospital of Henan University has used a combination of Chinese and Western medicine to treat allergic purpura and purpura nephritis with remarkable efficacy.
7. 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 into chronic. The course of the disease is usually about 1~2 weeks to 1-2 months, a few can be up to several months or more than a year. A small number of 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: (i) older age at onset; (ii) massive nephrotic proteinuria lasting more than 6 months; and (iii) renal biopsy pathology suggesting 50% crescent formation. The last thing I want to remind is also very important, allergic purpura patients do not forget to review urinary routine every 1-2 months within 2 years, because some patients with skin purpura 2 years before the occurrence of purpura nephritis.