### Date : 2024-05-09 11:29 ### Topic : #medicine ---- Henoch-Schönlein purpura (HSP), also known as IgA vasculitis, is a small vessel vasculitis that primarily affects children, though it can occur at any age. It's characterized by the **deposition of IgA immune complexes in small blood vessels, leading to inflammation**. This inflammation typically results in a **purpuric skin rash, abdominal pain, arthritis, and kidney involvement**. ### Clinical Features 1. **Skin**: The most distinctive feature of HSP is a purpuric rash, which usually appears as small red or purple spots predominantly on the lower legs and buttocks. The rash does not blanch when pressed.  2. **Gastrointestinal (GI) Tract**: Many patients experience GI symptoms, which can include abdominal pain, nausea, vomiting, and even bloody stools. These symptoms result from inflammation of the GI tract vessels. 3. **Joints**: Arthralgia or arthritis can occur, typically affecting the knees and ankles with swelling, pain, and sometimes redness. 4. **Kidneys**: Renal involvement can vary from mild hematuria (blood in the urine) to more severe cases resembling nephritic syndrome with proteinuria and renal insufficiency. ### Etiology The exact cause of HSP is unknown, but it is thought to involve an abnormal immune response in which IgA immune complexes deposit in small vessels, leading to inflammation. Triggers can include infections (particularly respiratory), medications, foods, and insect bites. Genetic factors may also play a role. ### Diagnosis Diagnosis is mainly clinical, based on the characteristic symptoms and signs. Additional tests can support the diagnosis or assess the severity: - **Blood tests**: Can show elevated inflammatory markers like C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR). - **Urine tests**: To check for kidney involvement. - **Imaging**: Abdominal ultrasound may be performed if there are significant GI symptoms. - **Biopsy**: A skin biopsy can confirm the presence of IgA deposits in small blood vessels. ### Treatment Treatment of HSP is primarily supportive, focusing on symptom management: 1. **Pain Relief**: NSAIDs (nonsteroidal anti-inflammatory drugs) are commonly used for joint pain and abdominal discomfort, but should be used cautiously if renal involvement is suspected. 2. **Corticosteroids**: These may be used in severe cases, especially when there is significant GI or renal involvement. 3. **Hydration and Rest**: Adequate hydration and rest are important during acute episodes. 4. **Monitoring**: Regular monitoring is essential, particularly for renal function, to catch and manage complications early. ### Prognosis Most cases of HSP resolve without long-term issues within a few weeks, though symptoms can recur in about a third of cases. Long-term complications are rare but most likely involve the kidneys, such as chronic kidney disease or rarely, end-stage renal failure. Therefore, ongoing monitoring of renal function is critical for those with renal involvement. Henoch-Schönlein purpura typically has a good outcome, especially in children, with most recovering fully without any serious consequences. Adults, however, may experience more severe forms of the disease and should be monitored closely for complications.