Henoch-Schönlein purpura (HSP), also known as anaphylactoid purpura, is a form of vasculitis that affects the small arterial vessels, mostly common in the skin, gastrointestinal tract and the kidneys. In about 50% of children the disease follows an upper respiratory infection. Many organisms and allergens have been suggested to trigger HSP including bacteria, viruses, medications, food, and vaccinations. The disease may be a result of an abnormal activation of the immune system in response to one of those triggers. HSP occurs throughout the year, but some studies have shown that there is an increase in cases during the fall and winter months.
HSP may occur in all age groups but is much less frequent in adults. HSP is the most common form of vasculitis in children, with an incidence of approximately 13 cases per 100,000 children per year. It has been observed that HSP tends to be less severe in children as compared to adults.
Most children present with the classical symptoms of skin rash, pain in the abdomen and arthritis. The typical skin lesions are called palpable purpura, a purple, raised rash most frequently affecting the legs and buttocks but can be seen in other parts of the body. Multiple joints may be painful with mild swelling but knees and ankles are most commonly affected. Arthritis in HSP typically does not cause joint damage. The abdominal pain is the result of intestinal involvement by the disease and it can be associated with nausea, vomiting, loss of appetite and blood in the stools. Children may rarely have intestinal intussusception, which is a potential severe complication caused by a bowel folding. Approximately 50% of patients may have inflammation affecting the kidneys but rarely developed permanent damage of the kidneys. Most children recover completely. Kidney inflammation is usually associated with the presence of microscopic blood and/or protein in the urine.
Boys can develop painful scrotal swelling.
The diagnosis of HSP is a result of several factors, including the presence of typical symptoms, a physical examination demonstrating findings such as skin lesions and arthritis, laboratory tests such as urinalysis that shows microscopic blood in the urine and stool that shows microscopic blood. A skin biopsy is sometimes obtained but is usually not needed to diagnose the disease. The biopsy typically shows vasculitis with deposits of immunoglobulin A. Other laboratory tests are frequently obtained to exclude alternative diagnoses.
For most children, HSP is a mild illness that resolves spontaneously, without any specific treatment other than medications for pain. However, it may cause long-term serious problems in the kidneys, and rarely in the bowels. The treatment of HSP is directed toward the most severe symptoms or signs of potential permanent injury or complication. For the majority of patients, joint and abdominal pain can be relieved by tylenol or by anti-inflammatory medications, such as naproxen or ibuprofen. Anti-inflammatory medications should be avoided in patients with kidney failure. Some patients may require cortisone medications, such as prednisone, especially those with significant abdominal pain, scrotal edema or persistent renal disease. Treatment with medications that suppress the immune system are reserved for patients with high risk for kidney damage (renal failure).
Complications from HSP are rare and include bowel bleeding, bowel intussusception, and kidney failure.
As mentioned before, for the majority of children the outcome of HSP is excellent with nearly all patients having complete resolution of the disease. The most common and serious long-term damage seen in HSP is chronic kidney failure. A minority of patients may experience a recurrence of the disease, weeks, months or even years after the initial illness. Some studies have suggested that HSP causes more severe kidney disease in adults as compared to children and therefore, more aggressive treatment is usually given to adults. In general, however, the disease has a very good prognosis for both children and adults.
Revision: September 2012
The Vasculitis Foundation gratefully acknowledges Dr. Alexandra Villa-Forte from the Cleveland Clinic, for her expertise and contribution in compiling this information.