Concept: Allergic purpura, also known as Hen-Y-Shu syndrome, is a vasculitis syndrome with small vasculitis as the main lesion. The clinical manifestations are idiopathic rash, often accompanied by arthralgia, abdominal pain, blood in the stool, hematuria and proteinuria. It mostly occurs in preschool and school-age children.
Allergic purpura rash characteristics: the rash is symmetrically distributed, often appear in batches, to the end of the limbs obvious, size varies, can be fused into a patch, bright red or purple-red color, later the color will become dark brown, purpura slightly elevated on the skin surface, pressure does not fade, can be accompanied by itching and pain, purpura can be accompanied by angioneurotic edema, at the same time there are joints are wandering pain, redness, abdominal pain, diarrhea, vomiting, blood in the stool, in serious cases It can cause kidney damage. If the lesion involves brain tissue, headache and epilepsy may occur; if the lesion involves respiratory tract, hemoptysis and pleurisy may occur.
Pathological changes: The basic pathological changes are widespread leukocytoclastic vasculitis, mainly capillary vasculitis, but also the veins and small arteries; collagen fiber swelling and necrosis, neutrophil infiltration, surrounded by scattered nuclear debris; interstitial edema, plasma exudate, and exuding red blood cells; endothelial cell swelling, thrombosis, lesions involving the skin, kidneys, joints and The lesions involve the skin, kidneys, joints and gastrointestinal tract, and a few involve the heart, lungs and other organs, and in the skin and kidneys, predominantly immune complex deposits are seen under fluorescence microscopy.
Etiology: The etiology of this disease is not yet known. It is generally believed that the possible triggering factors are: microbial (bacterial, viral, parasitic, etc.) infections, drugs (antibiotics, salicylates, isoniazid, phenobarbital, etc.), food allergies (fish, shrimp, eggs, dairy), vaccination, pollen allergy, mosquito bites, etc., but there is no definite evidence. In recent years, it is believed that streptococcal infection is closely related to the development of allergic purpura, and a part of the children have a history of upper respiratory tract infection before the onset of the disease.
Clinical manifestations.
1, skin purpura: the repeated appearance of skin purpura during the course of the disease is the characteristic of the disease, mostly seen in the limbs and buttocks, symmetrical distribution, more on the side of the body, appearing in batches, less on the face and trunk; initially purplish papules, higher than the skin surface, and then brown and fading, can be accompanied by urticaria and angioneurotic edema, severe children purpura can fuse into large blisters with hemorrhagic necrosis.
Gastrointestinal symptoms: more than half of the children have recurrent paroxysmal abdominal pain, located around the umbilicus or lower abdomen, with severe pain, may be accompanied by vomiting, but vomiting blood is rare; some children have black stool or bloody stool, diarrhea or constipation, occasionally complications of intestinal overlap, intestinal obstruction or intestinal perforation.
3. Joint symptoms: painful swelling of large joints such as knee, ankle, elbow, wrist, etc., restricted movement, single or multiple, often with fluid in the joint cavity, joint symptoms disappear quickly, or within a few months, leaving no sequelae.
4, renal symptoms: the most common renal lesion caused by this disease is secondary glomerular disease. Most of the children have hematuria, proteinuria and tubular pattern with increased blood pressure and swelling, called purpura nephritis, and a few have nephrotic syndrome; most of the renal symptoms appear within one month of the onset of the disease, and may occur later in the course of the disease, and a few have nephritis as the first symptom; although some children have hematuria and proteinuria lasting for months or even years, most of them can recover completely, and a few develop A few develop chronic nephritis and die of chronic renal failure. Risk factors for progression of renal disease include: massive proteinuria, edema, hypertension and renal hypoplasia, and renal biopsy is useful to understand renal pathology and guide treatment.
5. Others: Occasionally, intracranial hemorrhage may occur, leading to convulsions, paralysis, coma, aphasia, and also bleeding manifestations such as nasal bleeding, gum bleeding, hemoptysis, and testicular bleeding.
Treatment.
1, general treatment: there is no special treatment for this disease, the acute stage should be as far as possible bed rest, less activity, and actively looking for the cause.
2, symptomatic treatment: if there is infection should first anti-infection treatment, with urticaria or angioneurotic edema, the application of antihistamines and calcium; abdominal pain, the application of antispasmodic drugs; gastrointestinal bleeding should be fasted, can be sedated cimetidine, if necessary, blood transfusion.
3.Antioxidant therapy: take oral vitamin C tablets, 200 to 300 mg per day, divided into 2 to 3 oral doses.
4.Glucocorticoids: In the acute stage, abdominal pain and arthralgia can be relieved, but it cannot prevent the occurrence of kidney damage and cannot affect the prognosis. Prednisone 1 to 2 mg per kg per day, divided into oral doses, or dexamethasone, methylprednisolone daily intravenous drip, can be discontinued after the symptoms are relieved.
5. Anticoagulation therapy: drugs to stop platelet aggregation and thrombosis, aspirin 3 to 5 mg per kg daily or 25 to 50 mg per day taken once daily; dipyridamole (Pansentin) 3 to 5 mg per kg daily in divided doses; heparin, 0.5 to 1 mg per kg each time, 3 times on the first day, 2 times on the next day, and once daily thereafter for 7 days.
Evolution of the disease and prevention and management.
Allergic purpura is mostly self-limiting and usually improves within 6 to 8 weeks with a good prognosis; some cases can be recurrent for several years. The prognosis is good and some cases can recur for several years. Those with joint involvement are rarely left with joint deformities. The condition of the child is usually stable within 3 months and the chance of recurrence is rare. If purpura is prolonged beyond 3 months, the probability of recurrence increases. The most serious complications are caused by purpura nephritis, children who develop purpura nephritis can be cured as long as regular treatment, only a few cases develop into chronic nephritis, renal insufficiency, renal failure death cases only account for 0.1% of purpura nephritis. The acute phase should be bed rest and should be given an animal protein free diet, which is a vegetarian diet. Do not have chicken, duck, fish, shrimp, milk or all kinds of meat in your food. After treatment purpura disappears 1 month before you can resume animal protein diet, the principle of recovery period is to add animal protein-containing diet gradually like by like. 3 to 4 days add one kind, after eating no allergic reaction then add the second and third kind. This ensures safety and also facilitates the detection of the animal protein as the allergen. If the child has gastrointestinal bleeding, severe abdominal pain, or blood in the stool the diet should be temporarily prohibited.
Attention to diet.
Prohibit irritating foods such as raw onion, raw garlic, chili, alcohol; foods high in animal protein such as meat, seafood, eggs, milk; and convenience foods such as beverages and snacks. Do not take any vaccinations until the disease is cured. It must be 3 to 6 months after the disease is cured, otherwise it may lead to the recurrence of the disease.
Finally, parents should also be reminded that if they find bleeding spots on their children, they should pay attention to them and choose to go to a regular hospital for early diagnosis and treatment.