- What is Henoch-Schönlein Purpura?
- What does it look like (under the microscope)?
- How did I get it?
- What does it affect?
- What are the symptoms?
- How is it diagnosed?
- What is the treatment?
- What is the prognosis?
What is Henoch-Schönlein Purpura (HSP)?
HSP is a form of blood vessel inflammation- also known as vasculitis- that affects the small vessels called capillaries in the skin and the kidneys. The inflammation is due to an abnormal response of the immune system (due to the immune system product called IgA immunoglobulin).
What does it look like (under the microscope)?
In the skin, microscopy studies show IgA and C3 (a protein in the body) deposits in the blood vessel walls.
In the kidney, HSP is characterized by IgA deposits in the mesangium, which is part of the glomerulus where blood is filtered. These deposits can be seen on a microscope by the pathologist with a special staining called immunofluorescence The deposits will give a fluorescent glow under the microscope.
The pathologist can also use Light microscopy which magnifies the kidney by 10 to 100 times its original size, and can show a wide range of changes in the glomerulus. These may range from increased cells in the mesangium, increase in white blood cells, and abnormal cell growth in some parts of the glomerulus. Sometimes the pathologist will see the development of cell growths called crescents, named for their crescent or moon-like shape.
How did I get it?
HSP has no known cause; it occurs most often in the spring and frequently follows an infection of the throat or the respiratory tract. It seems to represent an unusual reaction of the body's immune system that is in response to this infection (either a bacteria or a virus). Aside from infection, certain medication can also trigger the condition. HSP occurs most commonly in children, but people of all age groups can be affected.
What does it affect?
It affects the skin, joints, bowels and the kidneys. Infrequently, problems in other areas of the body, such as the nerves, brain and lungs may occur.
This table shows how symptoms might appear in the specific affected body parts.
Affected Body Part |
Symptoms |
Kidney |
Red or tea colored urine, weight gain, swelling on legs |
Joints |
Joint pain and swelling of ankles knees and elbows |
Skin |
Rash in buttocks and legs, appearing as red or purple spots |
Gastrointestinal Tract |
Abdominal pain, nausea, vomiting, constipation or diarrhea, bowel obstruction, blood in the stools |
Lungs |
Cough, coughing up blood |
The table below describes the type of specialist you might see depending on your symptoms.
Affected Body Part |
Doctor |
Kidney |
Nephrologist |
Joints |
Rheumatologist |
Skin |
Dermatologist |
Gastrointestinal Tract |
Gastroenterologist/ Surgeon |
Nerves/ Brain |
Neurologist |
Lungs |
Pulmonologist |
What are the symptoms?
HSP usually causes a skin rash most prominent over the buttocks and behind the lower legs.
It could also result in joint pain and swelling (arthritis) and sometimes fever and cramping pain in the abdomen. The joints that are usually affected are the ankles and the knees. Inflammation of the blood vessels in the kidneys can cause blood and/or protein leak in the urine. Serious kidney complications are not common but can occur and can lead to advanced kidney disease. Symptoms usually last approximately a month.
How is it diagnosed?
No single laboratory test can confirm HSP, but certain tests can help detect the illness. Urine and blood tests for inflammation and kidney function can detect the presence of HSP. A biopsy of the skin, and less commonly kidneys, can be used to diagnosis vasculitis. Special staining techniques of the biopsy can be used to document the abnormal immune system product (IgA) deposits in the blood vessels of the areas involved.
What is the treatment?
There is no specific treatment for HSP. While HSP is generally a mild illness that resolves spontaneously, when it is severe it can cause serious problems in the kidneys and bowels.
The treatment of HSP will depend on the areas most significantly affected . Joint pain can be relieved by anti-inflammatory medications such as aspirin or ibuprofen (Motrin). Some patients require corticosteroid medications, such as prednisone or prednisolone, especially those with significant abdominal pain or kidney disease. With more severe kidney disease, involvement called glomerulonephritis or nephritis, cyclophosphamide (Cytoxan), azathioprine (Imuran), or mycophenolate mofetil (Cellcept) have been used to suppress the immune system. Infection, if present, can require antibiotics.
What is the prognosis?
The prognosis for HSP is generally excellent. Nearly all patients have no long-term problems. The kidney is the most serious organ involved when it is affected, and some patients might have serious long-term kidney damage. Rarely, patients will experience a bowel obstruction, for which surgery may be necessary.
The chance of the disease coming back is not high but can occur, usually in the form of skin rash, for months to a year after symptoms of HSP begin.
HSP in adults is generally more severe than in children. Adults have more severe kidney involvement and can require more aggressive treatment.
