Rheumatic purpura

Rheumatic purpura is an older term for the condition now usually called IgA vasculitis. It was also historically grouped under Henoch-Schönlein purpura. It is not the same as rheumatic fever.

IgA vasculitis causes inflammation in small blood vessels. IgA, or immunoglobulin A, is an antibody used by the immune system. In this condition, IgA collects in blood vessel walls and triggers inflammation.

The clearest sign is usually purpura: red or purple spots caused by bleeding beneath the skin. The spots do not fade when pressed and may feel raised. The condition can also affect the joints, digestive system, and kidneys.

Children are affected most often, but adults can develop it too. Many episodes settle within several weeks. Kidney inflammation is the main reason follow-up matters, because it can cause no obvious symptoms at first. Adults have a greater risk of lasting kidney problems than children.

The rash usually appears on both sides of the body. It is most common on the lower legs, ankles, and buttocks, although it may spread elsewhere. Pressure from socks, waistbands, or standing may make it more noticeable. New patches can appear in crops after older ones begin to fade.

On darker skin, the spots may look deep red, brown, or purple rather than bright purple. They are often easier to see in good natural light. The spots do not disappear when a clear glass is pressed firmly against them.

Other symptoms can include:

• Aching, swelling, or stiffness in the ankles and knees
• Cramping or aching abdominal pain
• Nausea, vomiting, or reduced appetite
• Blood in the stool or urine
• Swelling of the feet, lower legs, hands, face, or scalp
• Tiredness or a mild fever

Joint symptoms can make walking uncomfortable, but they usually do not cause permanent joint damage.

Digestive symptoms may begin before the rash. Abdominal pain can come and go, sometimes becoming intense. Boys and men may develop pain or swelling of the scrotum.

Kidney inflammation may cause blood or protein in the urine, high blood pressure, swelling, or reduced urine output. Small amounts of blood and protein are often found only through urine testing.

Rheumatic purpura develops when IgA becomes deposited in small blood vessels. Why this response occurs in one person and not another is not fully understood.

An upper respiratory infection, such as a cold or sore throat, often happens before an episode. Other infections can also act as triggers. Medicines, vaccinations, insect bites, and foods have occasionally been reported before symptoms, but this does not prove that they caused the condition.

It is not contagious. You cannot catch IgA vasculitis from another person, even when an infection appears to have triggered their episode.

The condition is not usually inherited in a simple way. It is more common in children than adults, but it can occur at any age. A previous episode increases the chance of another episode, particularly during the months after recovery.

There is no single blood test that diagnoses every case. A clinician usually considers the appearance and location of the rash together with joint, abdominal, or kidney symptoms.

Other causes of a non-fading rash must be considered. Some infections, blood disorders, medicines, and other forms of blood vessel inflammation can produce a similar rash.

Tests commonly include:

• Urine testing for blood and protein
• Blood pressure measurement
• Blood tests for kidney function, inflammation, and blood cell counts
• Stool testing if digestive bleeding is suspected

Blood IgA levels may be raised, but a normal result does not rule out the condition, and a high result does not confirm it by itself.

A skin biopsy may be needed if the rash is unusual or the diagnosis is uncertain. A small sample is examined for inflamed blood vessels and IgA deposits.

A kidney biopsy may be considered when there is substantial or persistent protein in the urine, reduced kidney function, or another sign of significant kidney inflammation. This helps show the type and severity of kidney injury.

Ultrasound or other imaging may be used for severe abdominal pain. It can look for complications such as intussusception, where one section of bowel slides inside another.

Many people need supportive care rather than treatment aimed at the immune system. This may include rest during painful periods, enough fluids, and suitable pain relief.

Paracetamol, also called acetaminophen, may help with pain. Anti-inflammatory medicines such as ibuprofen can sometimes ease joint symptoms, but they may not be suitable if there is kidney involvement, dehydration, stomach bleeding, or another medical concern. Medicine choices should be checked with a healthcare professional.

Corticosteroids like prednisone or hydrocortisone reduce inflammation. They may be used for severe abdominal or joint symptoms, or as part of treatment for certain kidney complications. They can improve some symptoms but are not routinely used simply to prevent kidney inflammation in everyone.

Kidney involvement may require care from a kidney specialist. Depending on its severity, treatment can include:

• Medicines that lower blood pressure and reduce protein loss in urine
• Corticosteroids or other medicines that suppress immune activity
• Treatment for fluid retention or reduced kidney function
• Dialysis in the uncommon event of severe kidney failure

Monitoring is an important part of management, even after the rash and pain have gone. Urine tests and blood pressure checks are usually continued for a period because kidney inflammation can appear later without causing noticeable symptoms. The timing and length of follow-up are based on age, test results, and the severity of the episode.

Kidney inflammation, called IgA vasculitis nephritis, is the main possible long-term complication. Most kidney findings are mild, but some people develop ongoing protein loss, high blood pressure, or reduced kidney function. Serious long-term kidney disease is more likely when initial kidney involvement is severe or does not improve.

Digestive inflammation can cause bleeding. A less common complication is intussusception, which can block the bowel and reduce its blood supply. Severe, repeated, or localised abdominal pain needs urgent assessment.

Other uncommon complications include inflammation affecting the testicles, lungs, brain, or nervous system. These are not typical of an uncomplicated episode.

Joint pain can be intense, but permanent joint damage is not expected. The skin spots may leave temporary brown staining as they heal.

There is no proven way to prevent rheumatic purpura. The immune response that causes it cannot usually be predicted, and common infections are not always avoidable.

Routine measures that reduce the spread of respiratory infections, such as handwashing and avoiding close contact when someone is unwell, are reasonable. However, they cannot guarantee prevention.

There is also no established diet, supplement, or activity plan that prevents another episode. If a particular medicine is suspected as a trigger, it should not be stopped or restarted without professional advice. The connection may be uncertain, and alternative treatment may be needed.

An episode often develops over days and lasts for several weeks. The rash may come and go in new crops. Joint and abdominal symptoms often improve before the final skin spots disappear.

Some people have another episode after seeming to recover. A recurrence may be milder, but it still needs attention to urine and blood pressure because kidney involvement can change from one episode to another.

Most children recover without lasting effects. Adults may take longer to recover and are more likely to have ongoing kidney abnormalities. An individual course cannot be predicted from the rash alone.

During active symptoms, walking or school attendance may be difficult because of ankle or knee pain. Activity can usually increase as comfort allows. The condition itself does not normally require long-term activity restrictions once symptoms have settled and kidney health is stable.

Keep planned follow-up appointments even if you feel well. Kidney problems may cause no pain and no visible change in urine. If urine tests, blood pressure, and kidney function remain normal through the recommended monitoring period, further condition-specific follow-up may not be needed.

People with persistent kidney involvement may need monitoring for months or years. This can include urine and blood tests, blood pressure checks, and treatment to protect kidney function.

Seek emergency care for a non-fading rash accompanied by fever, confusion, marked drowsiness, breathing difficulty, a stiff neck, or rapid worsening. A non-fading rash can have causes other than rheumatic purpura, including serious infection.

Emergency assessment is also appropriate for:

• Severe or rapidly worsening abdominal pain
• Vomiting blood, black stool, or substantial blood in stool
• Fainting, severe weakness, or signs of heavy bleeding
• Difficulty breathing or coughing up blood
• A seizure, sudden weakness, or a severe unusual headache

Seek urgent medical advice the same day for markedly reduced urine, visible blood in the urine, new facial or leg swelling, repeated vomiting, or severe scrotal pain and swelling.

A new unexplained non-fading rash should be assessed promptly, even if you otherwise feel well. If rheumatic purpura has already been diagnosed, arrange routine review for a returning rash, ongoing joint pain, or missed urine and blood pressure checks.

Is rheumatic purpura the same as IgA vasculitis?

Rheumatic purpura is an older name linked to what is now called IgA vasculitis. The newer name describes the underlying problem more clearly: inflammation of small blood vessels involving IgA antibodies.

Does the purple rash go away?

The spots usually fade as the blood beneath the skin is broken down. They may change from red or purple to brown before disappearing. New spots can appear while earlier ones are healing, and temporary staining may remain.

Can I catch it from someone else?

No. IgA vasculitis is an immune reaction, not a contagious illness. An infection may trigger it, but the vasculitis itself does not spread between people.

Will it damage my kidneys?

Many people have no lasting kidney damage. However, blood or protein can appear in the urine, sometimes without symptoms. Adults and people with more severe or persistent kidney findings have a greater risk of long-term problems, which is why monitoring matters.

Can rheumatic purpura come back?

Yes. Recurrences are possible, especially during the months after the first episode. A returning rash or other symptoms should be reviewed, and kidney checks may need to be repeated.

Do I need to change my diet?

There is no specific diet proven to cure the condition or prevent recurrence. If kidney function, blood pressure, or swelling is affected, a healthcare professional may recommend dietary changes suited to those findings.