Vasculitis allergica, also known as Schoenlein-Henoch purpura, is an inflammation of small and medium vessels in various organ systems, which is caused by an immune reaction. Preferably in the cold season, the disease usually begins one to three weeks after a previous infection of the upper respiratory tract and affects especially children in preschool and school age or adolescents. Even after taking medication, the disease is occasionally observed, which occurs somewhat more often in boys than in girls.
Allergic overreaction of the immune system as a cause
The Vasculitis allergica is probably based on an allergic overreaction of the immune system, which can be caused by various foreign proteins (antigens). Most of these antigens get into the body as components of pathogens, but also as part of drugs or insecticides, contact is possible.
The immune system reacts with the formation of IgA antibodies, which aggregate with the antigens into immune complexes. Their deposition in vessel walls triggers the said inflammatory reaction, which results in an increased permeability of the vessels in various organs. The events become visible at point-to-coin-sized skin hemorrhages.
Symptoms on different organs
Vascular disease in vasculitis allergica can cause symptoms on several organ systems:
- Skin: Eyes are usually found mainly on the extensor sides of the legs and the buttocks, usually symmetrically arranged, reddish-brown, palpable skin bleeding (purpura). The itchy spots and papules often flow into each other and can range from pinhead to coin size.
- Joints: Many children temporarily suffer from painful swelling of the ankle and knee joints and suddenly do not want to walk anymore.
- Bowel: Due to inflamed small bowel vessels more than half of the children complain of colicky abdominal pain, accompanied by nausea and vomiting. Bloody-slimy stools are common among these complaints.
- Kidneys: In about 30 percent of the patients, the renal vessels are affected, which is often noticeable after two to three weeks by detection of blood and possibly protein in the urine (so-called Schoenlein-Henoch nephritis).
The symptoms of allergic vasculitis are usually preceded by general malaise and mild fever.
Disease leads to the diagnosis
There is no specific laboratory test as evidence of allergic vasculitis. However, the doctor can usually make the diagnosis based on the characteristic skin symptoms associated with previous infection or medication. Sometimes it is possible to detect the circulating immune complexes in the blood.
Not infrequently, the symptoms of the intestinal tract precede the skin symptoms, making the diagnosis difficult. An ultrasound examination of the abdominal cavity and examinations of the stool for the detection of blood can also continue. To detect kidney involvement, repeated urinalysis is also required.
Therapy of allergic vasculitis
Bed rest is prescribed during the acute illness phase. In most of the patients, the symptoms improve without further treatment. For severe joint discomfort non-steroidal anti-inflammatory drugs are administered for relief, in case of intestinal involvement is treated with cortisone preparations.
If there is a kidney involvement over a longer period of time, a tissue sample can provide information about the extent of the damage. Maybe then a therapy with drugs for the suppression of the immune system (immunosuppressants) and cortisone is indicated.
Schubweiser course is characteristic
Typical of the purplish Schoenlein-Enoch is the bumpy course with recurrent abdominal pain and skin bleeding. Most of the time the disease is benign and cured after a few days, at the latest after 4 to 6 weeks, occasionally, the symptoms but over months or years repeatedly use.
In cases of intestinal involvement, in rare cases invagination of one section of the intestine into another (invagination) may occur. Particularly dreaded is the development of chronic nephritis with deterioration of renal function.