Henoch-Schönlein purpura (HSP) is an autoimmune disease (the immune system attacks the body). In the case of HSP, the small blood vessels in the skin become inflamed (a condition called vasculitis) and start leaking red blood cells, which causes a purplish, bruise-like rash on the legs, buttocks, and arms. HSP also affects the gastrointestinal tract and frequently the kidneys which can cause a cramping pain in the abdomen.
In addition, HSP:
- can occur at any age, but it most often affects children between the ages of 2 and 11.
- is the most common form of pediatric vasculitis (approximately 20 cases per 100,000 children per year).
- tends to affect boys more often than girls.
- is not contagious.
What are the symptoms of Henoch-Schönlein purpura?
Typical HSP skin rash
The main symptom of HSP is a painless rash (purpura) that usually appears on the legs, buttocks, and arms (though it can occur elsewhere). The rash starts off as red dots, then turns purple over a period of three to six days and looks like bruises. The rash does not change color when it is pressed on.
The symptoms of HSP are often preceded by cold and flu symptoms, such as fever, headache, nausea, loss of appetite, or diarrhea.
Aside from the rash, the other main symptoms of HSP are:
- Abdominal pain: Approximately two-thirds of children with HSP have abdominal pain, which may be accompanied by vomiting. Occasionally, blood may appear in a child’s vomit or stool. Blood in vomit or stool is a medical emergency and should be checked out by a doctor immediately. Rarely, patients develop an abnormal bowel folding called intussusception.
- Joint pain: Children with HSP often have swelling and tenderness in the knees, ankles, elbows, and wrists. The swelling usually lasts 1-3 days. Sometimes whole limbs will swell. The inflammation does not cause crippling arthritis.
Boys with HSP may also have painful swelling in the scrotum.
HSP can also affect the kidneys, and patients may have small amounts of blood in the urine. Between 20 and 50 percent of children with HSP have problems with their kidneys. The majority of these kidney problems resolve (get better) over 6 months.
Symptoms usually last between 2 - 12 weeks, typically about a month. Recurrences are not frequent but do occur.
What causes Henoch-Schönlein purpura?
The causes of HSP have not been identified. However, children who get HSP often have a cold or respiratory infection such as strep throat beforehand. In cases of HSP, the child’s immune system attacks the body’s cells during the respiratory infection, then continues the attack even after the infection is gone.
HSP has also been linked to insect bites and exposure to cold weather. In addition, it may be a reaction to some vaccinations, foods, drugs, or chemicals.
Who is affected by HSP?
HSP is the most common acute vasculitis affecting children, with an incidence of approximately 10 cases per 100,000 children per year. Although the syndrome is usually seen in children, people of any age may be affected. It is more common in boys than in girls.
How is Henoch-Schönlein purpura diagnosed?
Henoch-Schönlein purpura can be recognized by the combination of the purplish rash, abdominal pain, and joint inflammation (pain and swelling). However, children with HSP often have only the rash or joint pain. In these cases, the pediatrician has to rule out other diseases before diagnosing HSP.
The pediatrician may order one or more of the following tests to help with the diagnosis.
- Blood test. If HSP is affecting the child’s kidneys, a blood test may show high levels of two waste products, blood urea nitrogen and creatinine. Healthy kidneys keep the level of these two products low by filtering them out of the blood.
- Urinalysis. A urinalysis tests for blood or high levels of protein in the urine. The presence of either of these can indicate damage to the kidneys.
- Skin biopsy. In order to confirm vasculitis, a very small sample of skin may be taken to examine under a microscope.
How is Henoch-Schönlein purpura treated?
HSP is usually a mild illness that goes away on its own after 4 to 6 weeks (some cases can last as long as 12 weeks). There is no specific treatment for HSP, so the main goal is to relieve the symptoms. Over-the-counter medications such as acetaminophen (Tylenol) or ibuprofen (Motrin) can be used to relieve the pain. It is also important that the child rest and drink lots of fluids.
Once the symptoms of HSP disappear, the pediatrician may check the child’s kidney function by ordering blood tests or urinalysis over a period of several months. This is to make sure that the disease did not damage the child’s kidneys and that they are working properly.
What is the outlook for children who have had Henoch-Schönlein purpura?
The outlook for children who have had HSP is excellent; most patients have no long-term complications. About a third of children who have had HSP will get it again (recurrence). In those cases, the disease usually occurs within a few months and is less severe than the first time. More severe cases can cause complications in the future.
If the child developed any kidney problems from HSP, there is very good chance he or she will fully recover; only 1 percent of these children have kidney failure. Nevertheless, it is very important to follow up with the child’s pediatrician to help prevent any future complications.
Recent data shows that HSP in adults is generally more severe than in children. Adults have more severe kidney involvement and can require more aggressive treatment. The ultimate outcome, however, is usually very good for both adults and children.
- National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). Henoch-Schönlein purpura. Accessed 5/23/2013.
- National Heart, Lung, and Blood Institute. What is vasculitis? Accessed 5/23/2013.
- American College of Rheumatology. Vasculitis Accessed 5/23/2013.
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