Henoch Schonlein purpura (HSP) is an infection of the small blood vessels (vasculitis) that affects the skin, joints, intestines, and kidneys. As a result of deposits of a protein called IgA on the affected organs, it is also known as IgA vasculitis. HSP is more common in children under 10, but it can affect anyone. It usually clears up on its own within a month, but sometimes it causes serious complications, especially in the kidneys.
The exact cause of HSP is not known, but it may be triggered by an abnormal immune response to certain factors, such as:
Viral or bacterial infections, such as a cold, chickenpox, measles, or hepatitis
Medications, such as antibiotics, painkillers, or blood pressure drugs
Foods, such as cheese, chocolate, or shellfish
Insect bites, such as from a bee or a mosquito
Trauma, such as a fall, a cut, or a surgery
The main symptoms of HSP are:
There is a reddish-purple rash (purple) that is characteristic of HSP. It usually appears on the lower legs, buttocks, arms, and face and is often worse in areas that are under pressure, such as the sock line or waistline. Although it does not itch or hurt, the rash may feel warm when touched.
It is a common symptom of HSP that causes joint pain and swelling (arthritis). It usually affects the knees and ankles, though it can affect other joints as well, including the elbows, wrists, and fingers. The joint pain and swelling may come and go, and they usually subside when the rash clears.
A possible complication of HSP is abdominal pain and bleeding (gastrointestinal involvement). It is characterized by severe pain, nausea, vomiting, diarrhea, and blood in the stools. The abdominal pain may be colicky or crampy, and it may worsen after eating. Anemia or shock may result from mild to severe bleeding.
Another complication of HSP is kidney involvement, which can cause blood or protein in the urine, high blood pressure, swelling of the legs or face, and reduced urine production. End-stage renal disease or kidney failure may result from the problems with the kidneys, which can be temporary or permanent.
The diagnosis of HSP is based on the presence of the typical rash, joint pain, and abdominal symptoms. If one of these signs is missing, the doctor may order some tests to rule out other conditions and confirm the diagnosis, such as:
Blood tests. These can check for signs of inflammation, infection, anemia, or kidney function.
Urine tests. These can detect blood, protein, or other abnormalities in the urine that indicate kidney involvement.
Skin biopsy. This is a procedure that involves taking a small sample of skin from the rash and examining it under a microscope. The skin biopsy can show the deposits of IgA and the inflammation of the blood vessels.
Kidney biopsy. This is a procedure that involves taking a small sample of kidney tissue and examining it under a microscope. The kidney biopsy can show the extent of the kidney damage and guide the treatment decisions.
Symptoms of HSP usually go away on their own within a month, and no specific treatment is needed. However, some measures can help relieve the symptoms and prevent further complications, such as:
Rest and fluids. These can help the body heal and prevent dehydration.
Over-the-counter medications, such as acetaminophen or ibuprofen, may help relieve joint pain and abdominal pain, but aspirin should be avoided to prevent bleeding.
Inflammation and bleeding in the intestines and kidneys can be reduced by corticosteroids, which can be given either as pills or injections, depending on the severity of the condition. It is important to use them with caution and under the doctor's supervision, as they may cause some side effects, including weight gain, mood changes, or an increased risk of infection.
Some cases of severe or persistent kidney disease may require other medications, such as immunosuppressants, blood pressure drugs, or diuretics. These medications can help prevent or treat kidney failure.
Surgery. This may be required in rare cases of serious complications, such as a bowel obstruction or a rupture, or a kidney transplant.
There is no specific way to prevent HSP, as the exact cause is not known. However, some general measures can help reduce the risk of developing or worsening the condition, such as:
Avoiding the triggers. These may include the infections, medications, foods, insect bites, or trauma that may have triggered the immune response in the first place.
It is important to seek medical attention if symptoms of HSP develop or worsen, especially rash, joint pain, abdominal pain, or signs of kidney problems. Early diagnosis and treatment can help prevent or minimize complications.
In order to monitor the condition and kidney function, and to adjust the treatment if necessary, regular blood tests, urine tests, and blood pressure checks may be recommended, depending on the severity and duration of the condition.
