Henoch-Schönlein purpura (HSP) is a condition that causes small blood vessels to become inflamed. It leads to a distinctive skin rash, joint pain, stomach pain, and sometimes kidney problems. HSP can affect anyone, but it most commonly occurs in children under 11. Understanding the signs and getting timely care can make a real difference in recovery.
What Is Henoch-Schönlein Purpura?
Henoch-Schönlein purpura is a type of vasculitis — a condition where the immune system attacks the body’s own blood vessels. Specifically, it affects the smallest vessels, including capillaries, arterioles, and venules. This inflammation leads to leaking of blood into the skin and other tissues.
HSP is more common in males than females, at a ratio of about 2:1. Around 75% of all cases occur in children under the age of 11. However, teenagers and adults can develop it as well.
The good news is that HSP often clears up on its own without treatment. However, when the kidneys become involved, prompt and ongoing medical care becomes essential to prevent serious complications.
Causes and Risk Factors of Henoch-Schönlein Purpura
The exact cause of Henoch-Schönlein purpura is not yet fully understood. However, researchers believe it happens when the immune system mistakenly deposits a protein called immunoglobulin A (IgA) into the walls of small blood vessels. This triggers inflammation and damage.
HSP is closely related to a kidney condition called IgA nephropathy. Both involve elevated IgA levels in the blood, and their biopsy results look very similar. The main difference is which organs are affected and which age group is most at risk.
Known Triggers and Risk Factors
Several factors may trigger HSP in some people. These include:
Upper respiratory tract infections, such as strep throat
Bacterial or viral infections, including Streptococcus and parvoviruses
Certain vaccinations (for example, those for measles, typhoid, or cholera)
Some medications, including antibiotics and antihistamines
Insect bites or reactions to certain foods
In many cases, HSP appears a week or two after a respiratory infection. Therefore, parents should be aware of new rashes or symptoms following a cold or throat infection in their child.
For more background on vasculitis and how the immune system works, visit the Health Canada official health information portal.
Symptoms of Henoch-Schönlein Purpura
HSP produces a distinct set of symptoms. In fact, doctors often look for a classic trio: the purpura rash, joint pain, and abdominal pain. More recently, gastrointestinal bleeding has also been added as a key symptom to watch for.
The Purpura Rash
The skin rash is the most recognisable sign of HSP. It appears in 95 to 100% of all patients. The rash looks like small, raised, reddish-purple spots, usually found on the lower legs and buttocks. It can also appear on the arms, trunk, and areas under pressure, like the waistline.
The spots may look like bruises at first. However, unlike bruises, they are well-defined and slightly raised to the touch. In children, the rash can sometimes appear on the scalp or ears as well.
Joint and Abdominal Symptoms
Joint pain affects 60 to 80% of people with HSP. The knees and ankles are most commonly involved. The pain can be significant, but it generally does not cause permanent joint damage.
Abdominal pain and vomiting occur in about 85% of cases. The pain tends to come in waves (known as colicky pain). Some patients also experience changes in bowel habits, such as constipation or diarrhoea. Bloody stools can also occur in more serious cases.
Kidney and Other Symptoms
Kidney involvement affects more than 40% of HSP patients, especially when the condition progresses. Signs of kidney problems include blood in the urine (which may appear brick-red or tea-coloured) and protein in the urine.
In more serious cases, patients may develop nephrotic syndrome, which causes widespread swelling due to low protein levels in the blood. High blood pressure can also develop as a result of kidney strain.
Other symptoms include swelling of the hands, feet, scalp, or ears, and in some males, scrotal swelling.
To learn more about vasculitis-related conditions and their impact on children, see this helpful overview from the Mayo Clinic’s guide to Henoch-Schönlein purpura.
How Is Henoch-Schönlein Purpura Diagnosed?
Diagnosing Henoch-Schönlein purpura is largely based on clinical signs and a thorough medical history. There is no single test that confirms the diagnosis on its own. The doctor will look for the presence of the purpura rash plus at least one of the following:
Diffuse abdominal pain
IgA deposits in skin tissue (confirmed by skin biopsy)
Acute joint inflammation (arthritis)
Kidney involvement (shown by protein or blood in the urine)
Tests and Lab Work
Blood tests, including a complete blood count (CBC), often come back within normal ranges. However, lab work is still useful when complications are suspected. Your doctor may order the following:
Urinalysis: About 20% of patients show blood or protein in the urine, which signals kidney involvement.
Platelet count: Platelets are usually normal or slightly elevated in HSP. Importantly, they are never low — this helps rule out other purpura-causing conditions.
Creatinine and urea levels: These are elevated when there is kidney damage or dehydration.
Skin biopsy: This can confirm IgA deposits in the blood vessel walls.
Your family doctor or a specialist (such as a paediatric rheumatologist or nephrologist) can guide you through the diagnostic process. In Canada, your provincial health plan typically covers these diagnostic tests when ordered by a physician.
Treatment and Management of Henoch-Schönlein Purpura
Many cases of HSP resolve on their own within four to six weeks. For mild cases, treatment focuses on managing symptoms and keeping the patient comfortable. Rest, hydration, and over-the-counter pain relievers (like acetaminophen) are often recommended.
When Medical Treatment Is Needed
If symptoms are more severe, or if the kidneys are involved, your doctor may recommend additional treatment. Options can include:
Corticosteroids (such as prednisone) to reduce inflammation, particularly for severe abdominal or joint pain
Blood pressure medications if high blood pressure develops due to kidney involvement
Immunosuppressive therapy for serious kidney complications, prescribed by a specialist
Long-term follow-up is important for patients with kidney involvement. Your doctor will likely monitor kidney function through regular urine and blood tests for months or even years after the initial diagnosis.
Managing Symptoms at Home
For milder cases, especially in children, supportive care at home can be effective. Encourage rest during flare-ups. Make sure the child stays well hydrated. Avoid activities that put pressure on inflamed joints until the pain subsides.
Furthermore, keep track of any changes in urine colour, swelling, or new symptoms. Report these to your healthcare provider promptly.
When to See a Doctor
You should contact your family doctor or visit a walk-in clinic if you or your child develops a rash that looks like raised reddish-purple spots, especially on the lower legs. Do not wait to seek care if abdominal pain, bloody stools, or changes in urine colour also appear.
Go to the nearest emergency department if there is severe abdominal pain, significant blood in the urine, or signs of widespread swelling. These may indicate serious kidney involvement that needs immediate attention.
In Canada, most provincial health plans cover specialist referrals when your family doctor determines they are medically necessary. If you do not have a family doctor, a walk-in clinic can assess your symptoms and refer you as needed.
As always, please speak with a qualified healthcare provider before making any decisions about diagnosis or treatment. The information in this article is for general educational purposes only.
For additional trusted guidance on childhood inflammatory conditions, explore resources available through Healthline’s overview of Henoch-Schönlein purpura.
Frequently Asked Questions About Henoch-Schönlein Purpura
What are the first signs of Henoch-Schönlein purpura?
The first sign of Henoch-Schönlein purpura is usually a raised, reddish-purple rash on the lower legs and buttocks. Joint pain and abdominal pain often follow within a few days. In some cases, a recent cold or throat infection may precede these symptoms.
Is Henoch-Schönlein purpura serious?
In most cases, Henoch-Schönlein purpura is a self-limiting condition that resolves on its own within weeks. However, it can become serious when the kidneys are affected. Long-term kidney damage is the most significant complication, so regular monitoring is important.
Can adults get Henoch-Schönlein purpura?
Yes, adults can develop Henoch-Schönlein purpura, although it is far more common in children under 11. Adults who develop HSP tend to have a higher risk of serious kidney involvement. Therefore, adults should seek prompt medical evaluation if symptoms appear.
How long does Henoch-Schönlein purpura last?
Most cases of Henoch-Schönlein purpura clear up within four to six weeks. However, some patients experience relapses, particularly within the first few months. Kidney-related symptoms may persist longer and require ongoing follow-up care.
What triggers Henoch-Schönlein purpura in children?
Common triggers of Henoch-Schönlein purpura in children include upper respiratory infections, strep throat, and certain viral illnesses. Some cases have also been linked to specific medications or vaccinations. In many children, a cold or sore throat precedes the onset of symptoms by one to two weeks.
Does Henoch-Schönlein purpura affect the kidneys permanently?
Most children with Henoch-Schönlein purpura recover full kidney function without lasting damage. However, a small percentage of patients — particularly adults and those with severe kidney inflammation — may develop chronic kidney disease. Regular urine and blood tests help doctors monitor kidney health after diagnosis.
Key Takeaways
Henoch-Schönlein purpura is a form of vasculitis that mainly affects children under 11, but can occur at any age.
The classic symptoms are a raised purplish rash on the legs and buttocks, joint pain, and abdominal pain.
Kidney involvement affects more than 40% of patients and requires careful monitoring.
Most cases resolve on their own within four to six weeks with supportive care.
Severe symptoms — especially kidney-related signs — may require corticosteroids or specialist treatment.
In Canada, your family doctor, walk-in clinic, or provincial health system can connect you with the right care.
Always consult a healthcare professional for an accurate diagnosis and personalised treatment plan.
