Henoch-Schonlein purpura (also known as IgA vasculitis) is a disorder that causes the small blood vessels in your skin, joints, intestines, and kidneys to become inflamed and bleed.
The most striking feature of this form of vasculitis is a purplish rash, typically on the lower legs and buttocks. Henoch-Schonlein purpura can also cause abdominal pain and aching joints. Rarely, serious kidney damage can occur.
Henoch-Schonlein purpura can affect anyone, but it's most common in children between the ages of 2 and 6. The condition usually improves on its own. Medical care is generally needed if the disorder affects the kidneys.
The four main characteristics of Henoch-Schonlein purpura include:
- Rash (purpura). Reddish-purple spots that look like bruises develop on the buttocks, legs and feet. The rash can also appear on the arms, face and trunk and may be worse in areas of pressure, such as the sock line and waistline.
- Swollen, sore joints (arthritis). People with Henoch-Schonlein purpura often have pain and swelling around the joints — mainly in the knees and ankles. Joint pain sometimes precedes the classical rash by one or two weeks. These symptoms subside when the disease clears and leave no lasting damage.
- Digestive tract symptoms. Many children with Henoch-Schonlein purpura develop belly pain, nausea, vomiting and bloody stools. These symptoms sometimes occur before the rash appears.
- Kidney involvement. Henoch-Schonlein purpura can also affect the kidneys. In most cases, this shows up as protein or blood in the urine, which you may not even know is there unless you have a urine test done. Usually this goes away once the illness passes, but some people develop persistent kidney disease.
When to see a doctor
See your doctor if you have Henoch-Schonlein purpura and it's causing serious problems with your digestive tract.
If your child develops the rash associated with this condition, see your doctor as soon as possible.
In Henoch-Schonlein purpura, some of the body's small blood vessels become inflamed, which can cause bleeding in the skin, abdomen and kidneys. It's not clear why this initial inflammation develops. It may be the result of the immune system responding inappropriately to certain triggers.
Nearly half the people who have Henoch-Schonlein purpura developed it after an upper respiratory infection, such as a cold. Other triggers include chickenpox, strep throat, measles, hepatitis, certain medications, food, insect bites and exposure to cold weather.
Factors that increase the risk of developing Henoch-Schonlein purpura include:
- Age. The disease affects primarily children and young adults, with the majority of cases occurring in children between the ages of 2 and 6.
- Sex. Henoch-Schonlein purpura is slightly more common in males than in females.
- Race. White and Asian children are more likely to develop Henoch-Schonlein purpura than are black children.
For most people, symptoms improve within a month, leaving no lasting problems. But recurrences are fairly common.
Complications associated with Henoch-Schonlein purpura include:
- Kidney damage. The most serious complication of Henoch-Schonlein purpura is kidney damage. This risk is greater in adults than in children. Occasionally the damage is severe enough that dialysis or a kidney transplant is needed.
- Bowel obstruction. In rare cases, Henoch-Schonlein purpura can cause intussusception — a condition in which a section of the bowel folds into itself like a telescope, which prevents matter from moving through the bowel.