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Henoch-Schonlein Purpura (HSP)
or
Anaphylactoid Purpura

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Medical Author:

William C. Shiel Jr., MD, FACP, FACR

William C. Shiel Jr., MD, FACP, FACR

Dr. Shiel received a Bachelor of Science degree with honors from the University of Notre Dame. There he was involved in research in radiation biology and received the Huisking Scholarship. After graduating from St. Louis University School of Medicine, he completed his Internal Medicine residency and Rheumatology fellowship at the University of California, Irvine. He is board-certified in Internal Medicine and Rheumatology.

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Medical Editor:

Dennis Lee, MD

Dennis Lee, MD

Dr. Lee was born in Shanghai, China, and received his college and medical training in the United States. He is fluent in English and three Chinese dialects. He graduated with chemistry departmental honors from Harvey Mudd College. He was appointed president of AOA society at UCLA School of Medicine. He underwent internal medicine residency and gastroenterology fellowship training at Cedars Sinai Medical Center.

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Medical Editor:

Melissa Conrad Stöppler, MD

Melissa Conrad Stöppler, MD

Melissa Conrad Stöppler, MD, is a U.S. board-certified Anatomic Pathologist with subspecialty training in the fields of Experimental and Molecular Pathology. Dr. Stöppler's educational background includes a BA with Highest Distinction from the University of Virginia and an MD from the University of North Carolina. She completed residency training in Anatomic Pathology at Georgetown University followed by subspecialty fellowship training in molecular diagnostics and experimental pathology.

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What is Henoch-Schonlein purpura (HSP)?

Henoch-Schonlein purpura (HSP) is a form of blood vessel inflammation or vasculitis. There are many different conditions that feature vasculitis. Each of the forms of vasculitis tends to involve certain characteristic blood vessels. HSP affects the small vessels called capillaries in the skin and frequently the kidneys. HSP results in skin rash (most prominent over the buttocks and behind the lower extremities) associated with joint inflammation (arthritis) and sometimes cramping pain in the abdomen. Henoch-Schonlein purpura is also referred to as anaphylactoid purpura.

What causes HSP?

HSP occurs most often in the spring and frequently follows an infection of the throat or breathing passages. HSP seems to represent an unusual reaction of the body's immune system that is in response to this infection (either bacteria or virus). Aside from infection, drugs can also trigger the condition. HSP occurs most commonly in children, but people of all age groups can be affected.

What are symptoms of HSP?

Classically, HSP causes skin rash, pain in the abdomen, and joint inflammation (arthritis). Not all features need be present for the diagnosis. The rash of skin lesions appears in gravity-dependent areas, such as the legs. The joints most frequently affected with pain and swelling are the ankles and the knees. Patients with HSP can develop fever. Inflammation of the blood vessels in the kidneys can cause blood and/or protein in the urine. Serious kidney complications are infrequent but can occur.

Symptoms usually last approximately a month. Recurrences are not frequent but do occur.

How is HSP diagnosed?

HSP is usually diagnosed based on the typical skin, joint, and kidney findings. Throat culture, urinalysis, and blood tests for inflammation and kidney function are used to suggest the diagnosis. A biopsy of the skin, and less commonly kidneys, can be used to demonstrate vasculitis. Special staining techniques (direct immunofluorescence) of the biopsy specimen can be used to document antibody deposits of IgA in the blood vessels of involved tissue.