allergic purpura in children
Introduction
Introduction to allergic purpura in children Allergic purpura is a range of allergic vasculitis, which was described by Xu Lanshi and Henry in the 1930s and 1970s, and is also known as Schonlein-Henochvasculitis. This disease is the most common capillary allergic disease, with a wide range of small blood vessel inflammation as the pathological basis, skin purpura, gastrointestinal mucosal hemorrhage, joint swelling and nephritis are the main clinical manifestations. basic knowledge The proportion of sickness: 0.01% Susceptible people: seen in children Mode of infection: non-infectious Complications: abdominal pain, nephritis
Cause
Pediatric allergic purpura
Causes
Infection factor (26%):
The most common bacterial infection is -hemolytic streptococcus, followed by Staphylococcus aureus, Mycobacterium tuberculosis, Salmonella typhi, Pneumococcal and Pseudomonas. The above respiratory tract inflammation is more common, also seen in pneumonia, tonsillitis, scarlet fever. , bacillary dysentery, urinary tract infections, impetigo, tuberculosis and focal infections (skin, teeth, mouth, middle ear). There are rubella, flu, measles, chickenpox, mumps, hepatitis, etc. in the virus infection. Parasitic infections can also cause the disease, which is more common with aphid infections, as well as hookworms, whipworms, aphids, schistosomiasis, vaginal trichomoniasis, and malaria parasite infections.
Allergic factors (35%):
Allergic purpura is an autoimmune disease. The permeability and brittleness of capillaries are caused by the body's allergic reaction to certain allergic substances, resulting in hemorrhage and edema of subcutaneous tissue, mucosa and internal organs. Allergens can be caused by a variety of factors, but it is often difficult to find the exact cause of each specific case. It is generally believed that it may be related to a variety of predisposing factors, but direct pathogenic factors are often difficult to affirm.
Other factors (25%):
Insect bites, plant pollen, cold, trauma, menopause, tuberculin test, vaccination, and mental factors can all be caused. In addition, hemodialysis patients, lymphoma chemotherapy patients and Guillain-Barre syndrome patients have also reported allergic purpura.
Pathogenesis:
Aseptic vasculitis is the main pathological change of this disease. In addition to capillaries, small arteries and venules may also be involved. Skin lesions are mainly found in dermal blood vessels, which may have acute inflammatory reactions. See neutrophils and acidophilus around the blood vessels. Infiltration of cells, red blood cells exuded through the blood vessel wall, edema occurred, collagen fibers in adjacent blood vessels swelled, fibrous necrosis and interstitial edema in the blood vessel wall, necrotizing arteriitis in severe cases, and submucosal changes in the intestinal tract. Significant edema, hemorrhage, severe mucosal ulcers, renal changes mainly involving glomeruli, focal or diffuse injury, capillary endothelial hyperplasia, local fibrosis and thrombosis, focal necrosis, also visible crescent The lesions and fluorescence microscopy showed membranous and extensive proliferative changes in the glomerular capillary basement membrane, and IgG, C3 and granular fibrin deposition were observed. In a few cases, lesions may involve the heart, lung, pleura and craniocerebral vessels. Pathological changes.
Prevention
Pediatric allergic purpura prevention
If there is no nephritis, the prognosis is good, but the disease course is as long as 1 month to several months. It is easy to relapse. The interval between recurrences varies from several weeks to several months. If the intestinal bleeding is heavier, it is easy to control and the intracranial It is rare to see that the prognosis of this disease is mainly related to the nature of kidney disease. Some cases can be prolonged for several years, but most patients with mild kidney damage can gradually recover. A few severe cases can be associated with hypertensive encephalopathy and chronic renal failure. Most of them occur several years after the onset of nephritis. It has been reported that kidney disease or recurrent episodes in the first three months of the disease accompanied by nephropathy often have a poor prognosis.
Prevention of allergic purpura in children
1, pay attention to avoid contact with pathogens, such as pollen, chemicals, paint, gasoline, dust mites and so on.
2, children with allergies do not need to raise pets, try to reduce contact with animal skin, especially those who have already identified allergens should pay more attention.
3, pay attention to food hygiene, wash hands frequently, do not eat unclean fruits and aquatic plants, in order to eliminate the chance of intestinal parasite infection.
4, strengthen exercise, enhance physical fitness, improve the body's immunity to various infections, to avoid the cause of allergic purpura.
5, pay attention to climate change, timely increase or decrease clothes, prevent colds, regular ventilation in the room to keep the indoor air fresh.
6, before the condition has not healed, do not vaccinate various preventive vaccines, must be cured after 3 to 6 months, in order to prevent vaccination, otherwise it may lead to the recurrence of the disease.
Complication
Pediatric allergic purpura complications Complications abdominal pain nephritis
Children with skin purpura, 60% have abdominal pain symptoms, located in the umbilical or lower abdomen; 35% have renal inflammation urinary changes; 25% of joint swelling and pain, involving the limbs joints, leaving no joint deformity.
Symptom
Symptoms of allergic purpura in children Common symptoms Weak rash papules skin purpura punctate hemorrhage abdominal pain diarrhea hypertension nodules edema low fever
The incidence can be acute and slow, with acute morbidity mostly. Most children have a history of upper respiratory tract infection 1 to 3 weeks before onset, and may have non-specific manifestations such as irregular hypothermia, fatigue, and headache.
1. Skin symptoms: The rash is the main manifestation of this disease. It is more common in the distal extremity, dense around the ankle joint, followed by the buttocks and upper limbs. It can also occur on the face, the trunk is rare, the shape of the rash, and the color can be different. As a small urticaria or pink maculopapular rash, the pressure fades, and then the color deepens, forming erythema, punctate hemorrhage occurs in the center of the erythema, the color changes from pink to dark purple, which is purple sable, sable can be fused into pieces, and finally the color It turns brown and fades, leaving no traces. In addition, there are erythema and nodular erythema. Angioedema can be found in the head, eyelids, lips, kidneys and perineum, and sometimes there is tenderness in the swelling.
2. Digestive tract symptoms: more common, can be seen in the third of these two children, clinically known as abdominal type, the most common is abdominal pain, mostly severe colic, occurring in the umbilical cord, can also be seen in other parts, four points The third child may have tenderness, but also vomiting and vomiting, followed by bloody stools. In severe cases, bloody granules, vomiting blood is rare, often misdiagnosed as acute diarrhea, especially in the case of rash before the laparotomy Not a few, a small number of patients can be complicated by intussusception, occasionally intestinal obstruction, perforation, and hemorrhagic necrotic enteritis.
3. Joint symptoms: About half of the children may have multiple symptoms, migratory joint pain or arthritis, the lower extremities are more common, and the rash around the joints is more obvious. It is called "articular type" in the clinic. The liquid is mostly serous, and the joint symptoms disappear within a few days without leaving any deformation.
4. Renal symptoms: About one-third of children have nephritis. The younger the age, the more hematuria or microscopic hematuria, which usually occurs 2 to 4 weeks after purpura. It can also occur after the rash has subsided. Or the quiescent period of the disease, clinically known as "kidney type", the severity of the disease varies, the light is mostly, severe cases can occur renal dysfunction, azotemia and hypertensive encephalopathy, a few cases of hematuria, proteinuria or hypertension can be sustained 2 More than a year.
5. Other symptoms: mixed cases may have central nervous system symptoms, such as coma, optic neuritis, subarachnoid hemorrhage, Guillain-Barre syndrome, individual limb convulsions, 75% of children with EEG abnormalities, EEG The picture returned to normal in 6 to 20 months, severe cases may be due to myocardial hypoxia, ischemia caused by temporary abnormal ECG, occasionally complicated with acute pancreatitis orchitis and pulmonary hemorrhage.
Pathological changes aseptic vasculitis is the main pathological change of the disease. In addition to capillaries, small arteries and venules may also be involved. Skin lesions are mainly found in dermal blood vessels, which may have acute inflammatory reactions, and neutrophils are seen around the blood vessels. Eosinophilic infiltration, red blood cells through the blood vessel wall.
Examine
Examination of allergic purpura in children
The disease has no specific test and examination. When the amount of bleeding is high, it can show anemia, moderate white blood cells, normal or increased eosinophils, normal platelets, bleeding time, clotting time and blood clot contraction are normal, ESR increases, C reaction Protein and anti-streptolysin can be negative, pharyngeal culture can be seen in -hemolytic streptococcus group A, serum IgA is slightly increased, can be through urine, EEG and electrocardiogram, understand kidney, brain and heart conditions, to stool The occult blood test monitors the gastrointestinal bleeding, and the renal biopsy can determine the nature of nephritis, which has guiding significance for the treatment and prognosis.
Diagnosis
Diagnosis and diagnosis of allergic purpura in children
1, idiopathic thrombocytopenic purpura: according to the rash morphology, distribution and platelet count are generally not identified, angioedema is common in allergic purpura and not seen in thrombocytopenic purpura.
2, abdominal surgery before the appearance of rash, if there is acute abdominal pain, should be differentiated from appendicitis, when bloody stools, must be identified with intussusception or Meckel's diverticulum, allergic purpura with abdominal pain as the earliest main symptoms Most of them are seen in older children. For those with acute abdominal pain during childhood, the possibility of allergic purpura should be considered. A comprehensive examination of the skin, kidneys and joints is required.
3, bacterial infection meningitis dysbacteremia, subacute bacterial endocarditis and other sepsis can appear purpura, sometimes need to identify, these diseases caused by purpura due to thrombosis, the center of necrosis, but more children Sudden acute illness, generally rapid and critical, angiogenesis is often positive.
When the symptoms of the kidney are prominent, it should be differentiated from acute glomerulonephritis. Anyone with chronic kidney damage should ask if they have had allergic purpura in the past.
