Henoch-Schonlein Purpura (HSP)

Henoch-Schonlein purpura (HSP) is a form of vasculitis that affects blood vessels and is characterized by the deposition of immune complexes containing IgA antibodies. It is also known as IgA vasculitis or anaphylactoid purpura.

Causes and Risk Factors

The exact cause of HSP is unknown, but it is believed to be triggered by an abnormal immune response to certain infections, such as streptococcal pharyngitis or other bacterial or viral infections. Other potential triggers include vaccinations, medications, and food allergies.

Symptoms

The symptoms of HSP can vary in severity and may include:

• Purpura: a rash characterized by small, red-purple spots that can appear anywhere on the body, but are most commonly found on the legs, buttocks, and elbows.
• Joint pain and swelling: arthritis can occur in some cases, affecting the knees, ankles, and wrists.
• Abdominal pain: some people may experience abdominal pain, nausea, vomiting, and diarrhea due to gastrointestinal involvement.
• Kidney problems: HSP can cause kidney inflammation (nephritis), which can lead to blood in the urine, proteinuria, or kidney failure in severe cases.

Diagnosis

The diagnosis of HSP is based on a combination of clinical presentation, laboratory tests, and biopsy results. Diagnostic criteria include:

• Purpura: the presence of a characteristic rash.
• IgA deposition: the presence of IgA antibodies in affected tissues, as demonstrated by immunofluorescence or electron microscopy.
• Exclusion of other causes: ruling out other conditions that may cause similar symptoms, such as thrombocytopenia or other forms of vasculitis.

Treatment and Management

Treatment for HSP is primarily supportive and focused on managing symptoms. This may include:

• Pain management: using over-the-counter pain medications, such as acetaminophen or ibuprofen, to relieve joint and abdominal pain.
• Corticosteroids: in some cases, corticosteroids may be prescribed to reduce inflammation and prevent complications.
• Rest and hydration: getting plenty of rest and staying hydrated can help alleviate symptoms.

Complications and Prognosis

Complications of HSP can include:

• Kidney damage: in severe cases, HSP can cause permanent kidney damage or failure.
• Gastrointestinal bleeding: abdominal pain and gastrointestinal involvement can lead to bleeding or intussusception (a condition where the intestine telescopes into itself).
• Orchitis: inflammation of the testicles can occur in some cases, leading to testicular atrophy or infertility.

The prognosis for HSP is generally good, with most people recovering within a few weeks to months. However, some individuals may experience persistent or recurrent symptoms, and complications can occur in severe cases.