Anaphylactoid purpura

NHS Choices Syndication

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Anaphylactoid purpura


Henoch-Schönlein purpura (“hen-awk shern-line purr-purr-ah”) is a rare condition, usually seen in children, that causes blood vessels to become inflamed. It results in a skin rash and joint and tummy pain. 

The medical term for inflammation of the blood vessels is “vasculitis”, which means they get irritated and swollen. This inflammation can cause the small surface blood vessels to bleed into the skin, which results in the rash commonly seen in Henoch-Schönlein purpura (HSP). It can also affect blood vessels in the bowel and the kidneys.

HSP usually gets better without treatment and is not usually serious.

What are the symptoms?

HSP typically causes:

  • a skin rash (purpura) that looks like small bruises or reddish-purple spots, usually on the buttocks, around the elbows and on the legs, and sometimes also on the face and upper body
  • pain in the joints such as the knees and ankles, which also become swollen, tender and warm  
  • tummy pain, which tends to come on after the rash has developed but can occur beforehand 

It can also result in:

  • small amounts of bleeding in the intestines and the kidneys  blood may be seen when your child passes stools or urine 
  • flu-like symptoms such as fever, nausea and vomiting

Symptoms usually last for about four to six weeks.

What are the possible complications?

Rarely, HSP can cause potentially serious complications, such as:

  • inflammation of the kidneys (glomerulonephritis for most people this eventually gets better, but in a small proportion it can lead to kidney failure
  • inflammation of the testes (in boys), known as orchitis  this causes pain, redness and swelling of the scrotum
  • an abnormal folding in the gut called intussusception, which causes a blockage in your bowel that may need surgery

What is the cause?

HSP is caused by your immune system not working properly. It occurs most often in the spring, usually after an upper respiratory infection such as a sore throat, cough or cold.

The exact cause is unknown. It might be triggered by a bacterial or viral infection, a medicine, an insect bite, or exposure to chemicals.

HSP is not contagious. It occurs most often in children aged two to 11 years, but it can affect anyone. 

How is it diagnosed?

Your GP may suspect HSP just by listening to your symptoms and medical history. You may need to be referred to a hospital doctor for a diagnosis.

To help with the diagnosis, they sometimes perform the following tests:

  • blood tests to see how well the kidneys are working, or to look for recent signs of infection
  • urine dipstick test  this is used to detect traces of blood or protein in the urine, as the kidneys can sometimes be inflamed (this tends to develop weeks or months after the rash has gone)
  • stool test  to look for signs of blood in the poo
  • skin biopsy  a very small sample of skin is sent to the laboratory to be examined under a microscope 

How is it treated?

HSP is not usually serious. The rash, joint pains and tummy pain usually get better over days or weeks without needing any treatment.

Anti-inflammatory medicines such as ibuprofen or painkillers such as paracetamol may help relieve some of the joint pain. Resting will also help.

Sometimes, steroid medication like prednisolone can help severe stomach pain.

Your doctor will want to test your urine and blood pressure regularly for several months to check for kidney problems.

Testing your child’s urine

If your child has been diagnosed with HSP, they will need to have their urine tested on a regular basis for six months. This is either performed by yourself or by a nurse (either at the hospital or one who visits your home).

The dipstick test looks for microscopic amounts of blood or protein in your child’s urine.

You’ll need to collect the first urine your child does in the morning in a clean container. Urine collected later in the day might have a falsely high level of protein in it.

If required, your GP or a nurse will show you how to dip the urine with the dipsticks and read off the protein and blood levels.

Typically, this test is done frequently in the first few weeks, then monthly, unless your doctor tells you to do it more often. It should be continued for six months.

What to do if blood is detected

When blood is seen on the dipstick for the first time, you will need to inform the hospital.

Blood detected on the dipstick is not usually a cause for concern and often continues for several months in HSP. The urine will need to be dipped about once a month until it goes. No further action is needed if your child is well.

If the urine looks red, rusty coloured or bloody to the naked eye, contact the hospital so doctors can check your child’s kidneys.

What to do if protein is detected

  • If the protein is + or ‘trace’  do the dipstick test as requested until your child is seen in outpatients. No further action is needed unless the amount of protein is increasing.
  • If the protein is ++ or more  do the dipstick test again the next day. If it is still ++ or more of protein, phone the hospital so doctors can check your child’s kidneys. You will probably be asked to collect one or more early morning urine samples to be sent to the lab, and blood tests may be necessary.

When to contact the hospital

Contact the hospital if:

  • your child’s urine is red, rusty or blood coloured
  • your child’s urine has ++ or more of protein on the urine dipstick two days in a row
  • joint swelling is very painful, especially if it stops your child walking
  • your child has severe tummy ache, vomits green fluid (bile) or has blood in their poo
  • your son’s testicles are swollen or painful
  • your instincts as a parent tell you something is seriously wrong with your child


Usually, HSP gets better on its own within about four weeks and needs urine testing for six months, but generally doesn’t cause any lasting problems.

However, some people who have had HSP will get it again.

Kidney inflammation usually gets better without any complications or the need for treatment, but rarely it can lead to kidney failure or kidney damage. It is important to monitor any early signs of kidney problems with the regular urine tests, as instructed by your doctor.

Published Date
2014-06-23 14:19:49Z
Last Review Date
2012-11-14 00:00:00Z
Next Review Date
2014-11-14 00:00:00Z
Abdominal pain,Aches, pains and soreness,Bleeding,Blood,Blood in urine,Blood tests,Children,Chronic renal failure,Faeces,Flu-like symptoms,Gut,Joint pain,Joints,Kidney,Kidney disease,Kidney infections,Proteins,Rashes and skin problems,Skin,Spring,Stomach ache,Swollen joints,Symptoms and signs,Testicles,Urinary problems,Urine,Urine tests

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