Diagnosis
Your doctor will be able to diagnose the condition as Henoch-Schonlein purpura if the classic rash, joint pain and gastrointestinal symptoms are present. If some of these signs and symptoms are missing, your doctor may suggest one or more of the following tests.
Lab tests
No single test can confirm Henoch-Schonlein purpura, but certain tests can help rule out other diseases and make a diagnosis of Henoch-Schonlein seem likely. They may include:
- Blood tests. Your blood may be tested if your diagnosis isn't clear based on your signs and symptoms.
- Urine tests. Your urine may be tested for evidence of blood and to determine if your kidneys are still working properly.
Biopsies
People who have Henoch-Schonlein purpura often have deposits of a certain antibody on their skin. Your doctor may take a small sample of skin to be examined under a microscope. In cases of severe kidney involvement, your doctor may suggest a kidney biopsy to help guide treatment decisions.
Imaging tests
Your doctor may recommend an ultrasound to rule out other causes of abdominal pain and to check for possible complications, such as a bowel obstruction.
Source: http://www.mayoclinic.com