Henoch-Schonlein purpura (HSP) is inflammation of the blood vessels in the skin and other body organs. When it involves the skin, it causes a telltale rash. The rash looks like bruising or small dots in the skin, referred to as purpura.


HSP is caused by an abnormal reaction of the immune system. Normally, the immune system marks and attacks foreign items like viruses and bacteria. However, with HSP, the immune system attacks the blood vessels. It is not clear why the immune system attacks the body.

The change in the immune system may be triggered by:

  • Bacterial or viral infections
  • Certain medications
  • Recent exposure to certain vaccines
  • Infection by insect bites

HSP occurs most often after a respiratory infection. HSP is not contagious.

Risk Factors

HSP is most common in children aged 2 to 11 years old, but it can occur at any age. Factors that increase your risk of HSP include:

  • Recent upper respiratory illness, such as a cold
  • Recent exposure to vaccines, chemicals, cold weather, or insect bites


Symptoms may last for 4 to 6 weeks and may include:

  • Skin rash:
    • Reddish-purple spots that can be felt and are not itchy
    • Often appears on the buttocks or legs, may appear on the elbows
    • Red spots of various sizes
    • Bruising, usually below the waist
  • Pain in the joints, especially knees and ankles
  • Abdominal pain
  • Blood in the urine
  • Swelling of the ankles
  • Swelling of the scrotum in males
  • Fever
  • Blood in the stool
  • Vomiting


You will be asked your symptoms and medical history. A physical exam will be done.

Your bodily fluids, tissues, and waste may be tested. This can be done with:

  • Blood tests
  • Urinalysis
  • Stool sample
  • Skin biopsy from an area of the rash

Skin Biopsy

Skin proceedure
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HSP usually gets better on its own. Your doctor may prescribe medications if symptoms or complications are causing problems. Medications may include:

  • Nonsteroidal anti-inflammatory drugs (NSAIDs)—to lessen joint pain and arthritis
  • Steroid medication—for significant abdominal pain, joint pain, or kidney disease
  • Antibiotics—to treat bacterial infection
  • Immune system suppressants when you have symptoms of severe kidney disease


There are no guidelines to prevent HSP. Relapse occurs in about half of all cases.

It is important to make sure that you have long-term, follow-up visits with your doctor to be sure that kidney disease doesn't develop.