Arthritis. Joint inflammation, involving pain and swelling, occurs in approximately three-quarters of cases, particularly affecting the knees and ankles. It usually lasts only a few days and does not cause any long-term, chronic joint problems.
Abdominal pain. In more than half of people with HSP, inflammation of the gastrointestinal tract may cause pain or cramping; it may also lead to loss of appetite, vomiting, diarrhea, and occasionally blood in the stool.
In some cases, patients may have abdominal pain before the rash appears. In rare cases, an abnormal folding of the bowel (intussusception) may cause a bowel blockage, which may require surgery to fix.
Kidney impairment. HSP can cause kidney problems, indicated by such signs as protein or blood in the urine. This is usually only discovered on urine testing, since it does not generally cause any discomfort.
In most patients, the kidney impairment is mild and goes away without any long-term damage. It's important to monitor the kidney problems closely and make sure they clear up, since about 5% of patients may develop progressive kidney disease. About 1% may go on to develop total kidney failure.
Henoch-Schonlein Purpura Diagnosis and Treatment
The diagnosis of HSP may be clear when the typical rash, arthritis, and abdominal pain are present. A doctor may order some tests to rule out other diagnoses, confirm the diagnosis, and assess its severity.
Occasionally, when the diagnosis is uncertain, particularly if the only symptom is the classic rash, your doctor may perform biopsies of the skin or kidney. Urine and blood tests will likely be done to detect signs of kidney involvement and may need to be repeated during follow-up to monitor any changes in kidney function.
Although there is no specific treatment for HSP, you can use over-the-counter pain medicines, such as acetaminophen or nonsteroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen and naproxen for joint pain. In some cases, corticosteroid medication may be used.
The rash and joint pain will usually go away after four to six weeks without causing any permanent damage. Bouts of the rash may recur in approximately one-third of cases, but they are usually milder, do not involve joint and abdominal symptoms, and they clear up on their own.