Henoch-Schönlein purpura (HSP) is a form of vasculitis, which is the inflammation of blood vessels. It primarily affects small blood vessels and is most commonly seen in children, though it can occur in adults as well. HSP is characterized by a group of symptoms that include a purplish rash, joint pain, abdominal pain, and kidney problems.
Key Features of HSP:
- Purpura (Rash): The hallmark of HSP is a purplish rash, typically found on the legs and buttocks. The rash is caused by bleeding underneath the skin due to inflammation of the small blood vessels (capillaries). The rash is often raised and may be palpable, meaning you can feel the bumps under the skin.
- Arthritis or Joint Pain: Many individuals with HSP experience joint pain, often in the knees and ankles. This is due to inflammation in the joints and can sometimes mimic arthritis. Joint pain is usually temporary and resolves as the condition improves.
- Abdominal Pain: Abdominal discomfort or pain is common in HSP. This can range from mild cramps to more severe pain, and it may be associated with nausea, vomiting, or even gastrointestinal bleeding. In some cases, the abdominal symptoms may be so severe that they lead to an initial misdiagnosis of an abdominal emergency, such as appendicitis.
- Kidney Involvement: In some cases, HSP can cause glomerulonephritis, which is inflammation of the kidneys. This can result in blood in the urine (hematuria) or protein in the urine (proteinuria). In severe cases, kidney damage can occur, but most people recover kidney function with appropriate treatment.
- Other Symptoms: Less common features of HSP include testicular pain (in males), neurological symptoms (such as headaches or seizures), and elevated blood pressure.
Cause:
The exact cause of HSP is unknown, but it is often triggered by an infection, especially an upper respiratory infection, such as streptococcal throat infection. Other factors, such as vaccinations, medications, and certain foods, may also trigger the condition in some people. HSP is thought to be related to an abnormal immune response, where the body's immune system mistakenly attacks the blood vessels.
Diagnosis:
Diagnosing HSP is based on clinical symptoms and a physical examination. The presence of the characteristic rash, joint pain, abdominal symptoms, and possible kidney involvement is usually sufficient for a diagnosis. However, additional tests may be used to confirm the diagnosis and rule out other conditions:
- Urine tests: To check for kidney involvement, such as blood or protein in the urine.
- Blood tests: To look for signs of inflammation, such as elevated C-reactive protein (CRP) or erythrocyte sedimentation rate (ESR).
- Biopsy: In some cases, a biopsy of the skin or kidney may be performed to confirm the presence of immune deposits in the blood vessels, which is a hallmark of HSP.
Treatment:
Most cases of HSP are self-limited, meaning they improve on their own over time, often without the need for specific treatment. However, treatment may be required to manage symptoms or prevent complications:
- Pain Relief: Over-the-counter pain relievers like acetaminophen or ibuprofen may be used to relieve joint pain or abdominal discomfort.
- Corticosteroids: For more severe cases, such as those with significant abdominal pain or kidney involvement, steroids (prednisone) may be prescribed to reduce inflammation and control symptoms.
- Kidney Monitoring: Kidney function should be monitored regularly, especially in cases where kidney involvement is suspected, as HSP can lead to long-term kidney damage in rare cases.
- Plasma exchange or immunosuppressive drugs: In very severe cases or when there is significant kidney involvement, treatments such as plasma exchange (plasmapheresis) or stronger immunosuppressive drugs may be required.
Prognosis:
In most cases, HSP resolves on its own within a few weeks to months, and people make a full recovery without long-term issues. However, about 20-50% of people may experience a recurrence of the condition, especially in the first few months after the initial episode. The risk of recurrence tends to decrease over time.
- Kidney complications: About 10-30% of individuals may experience kidney problems that persist after the initial episode, such as proteinuria or hematuria. In rare cases, kidney failure may occur.
- Long-term outcomes: Most children with HSP recover fully with no long-term effects, but adults may be at higher risk for chronic kidney disease if they have significant kidney involvement during their illness.
