Henoch-Schonlein purpura (HSP)

Henoch-Schonlein purpura (HSP)

Henoch-Schonlein purpura is a disease which causes irritation and swelling of the small blood vessels in the skin resulting in a rash (purple spots or purpura). The illness usually affects children from 2 to 10 years of age.

Key points to remember

  • HSP causes inflammation of the small blood vessels in the skin causing a rash
  • HSP can also affect blood vessels around the kidneys and intestines
  • HSP can cause joint pain
  • HSP occurs most often in children from 2 to 10 years of age
  • the cause of HSP is unknown
  • the HSP rash itself is not 'catching' (contagious)
  • pain relief (such as paracetamol) can help the joint pain. You must follow the dosage instructions on the bottle. It is dangerous to give more than the recommended dose
  • return to your doctor if there is increasing pain, swelling, blood in your child's poo (stools) or wee (urine) or if you are worried at all
  • long-term follow-up for urine and blood pressure checks is very important to detect kidney disease

What is it?

HSP is also known as anaphylactoid purpura or vascular purpura.

HSP results from blood vessels becoming inflamed (irritated and swollen). This inflammation is called vasculitis. The vasculitis affects the small blood vessels in the skin, causing a rash (purple spots called purpura). It can also affect blood vessels around the joints, in the intestines and in the kidneys.

What causes it?

The cause of HSP is unknown. It might be triggered by bacterial or viral infections, medicines, insect bites or exposure to chemicals or cold weather. It occurs most often in the spring, usually after an upper respiratory infection, like a cold.

HSP usually affects children from 2 to 10 years of age, but it can happen in anyone. HSP itself is not catching (contagious). Doctors don't know how to prevent HSP.

What are the signs and symptoms?

  • skin rash: this may start out looking like red spots, bumps or raised red skin welts which can be itchy. This quickly changes to small bruises or reddish-purple spots that are often raised; it usually appears on the buttocks, on the legs and around the elbows. Blisters and/or ulcers may develop in the affected areas
  • pain and swelling in the joints (such as the knees and ankles) which can come and go and can move around from joint to joint
  • tummy pain, which can come and go and in some cases can be severe 
  • blood in the poo (stools): this is caused by the blood vessels in the bowel becoming inflamed (irritated and swollen) and can indicate more serious problems (such as an abnormal folding of the bowel called intussusception)
  • blood in the wee (urine): this is caused by the blood vessels in the kidney becoming inflamed (irritated and swollen). Serious kidney problems don't happen very often, but they can occur
  • swelling: many children with HSP also have swelling over the backs of their feet and hands, and the scrotum in boys

How is it diagnosed?

There is no specific laboratory test for the disease. The diagnosis of HSP is made by evaluating the signs and symptoms. Your doctor may order blood tests to exclude other conditions. If the diagnosis is suspected, your child will have urine tests to look for possible kidney involvement.

What is the treatment?

Fortunately, HSP usually gets better without any treatment. Pain relief (such as paracetamol) can help the joint pain. You must follow the dosage instructions on the bottle. It is dangerous to give more than the recommended dose.

Your doctor may recommend a drug called prednisolone. This can help people with severe stomach pains or very painful joints.

How long does it last?

The illness lasts 4 to 6 weeks in most patients. The rash (purpura) changes from red to purple, becomes rust-coloured and then fades completely.

About one-third of those with HSP can get it again, usually within 4 months of the initial illness. Repeat episodes of the illness are usually milder and shorter and more common in patients with kidney involvement. 

What are the complications?

Most people with HSP get better over time without treatment and have no long-term problems. About 5 percent of those with HSP develop long-term kidney disease (called glomerulonephritis). This may occur in the first week or so of the illness, but there may be a delay of weeks or months before it appears. Your doctor will want to check urine samples and blood pressure several times after the HSP goes away to check for kidney problems. These checks should go on for at least 6 months and some doctors recommend a blood pressure and urine check every year for life.

For information about glomerulonephritis, see:

  • MedlinePlus (U.S. National Library of Medicine National Institutes of Health)

When should I seek help?

Return to your doctor or the hospital if your child has one or more of the following or if you are worried for any other reason:

  • increasing tummy pains
  • swelling and pain that is not responding to pain relief
  • blood in the poo (stool) or wee (urine)

This content has been adapted from The Royal Children's Hospital (Melbourne) Kids Health Info for parents: Henoch-Schonlein purpura (HSP) [Accessed 11/04/2017]

Images of HSP (Henoch-Schonlein purpura) on this page have been reproduced, with permission, from the website of the New Zealand Dermatological Society Incorporated. Published online at dermnet.org.nz

This page last reviewed 28 April 2015.
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