IgA Vasculitis (Henoch-Schönlein Purpura)
What is IgA vasculitis?
IgA vasculitis (IgAV, also known as Henoch-Schönlein purpura) is part of the vasculitis group of illnesses. Vasculitis is a general term that refers to the inflammation (irritation and swelling) of blood vessels.
Each form of vasculitis tends to involve certain characteristic blood vessels. IgAV affects the small blood vessels in the skin, gastrointestinal tract and, frequently, the kidneys.
Who is affected by IgA vasculitis?
IgAV is the most common acute vasculitis affecting children (approximately 10 cases per 100,000 children per year). Although the syndrome is usually seen in children, people of any age may be affected. It is more common in boys than in girls.
IgAV occurs throughout the year, but some studies have shown that there is an increase in cases during the fall and winter months. IgAV is not spread by person-to-person contact.
What causes IgA vasculitis?
The cause of IgAV is currently unknown. IgAV often occurs after an infection of the throat or breathing passages (often strep throat). IgAV may represent an unusual reaction of the body's immune system in response to this infection (either bacteria or virus).
What are the symptoms of IgA vasculitis?
IgAV can cause skin rash, pain in the abdomen, and arthritis, and may cause kidney inflammation. Symptoms can last 2 to 12 weeks; most often, they last about a month. Recurrences (return of symptoms) are not frequent, but do occur.
These are the parts of the body that are usually affected by IgA vasculitis:
- Skin: There is often a red-purple, raised rash on the legs, buttocks or elsewhere. This is caused by red blood cells that leak out of the damaged blood vessels.
- Joints: The joints most often affected by pain and swelling are the ankles and the knees. Usually, this only lasts from one to three days in the individual joints. Sometimes, whole limbs will swell. The inflammation usually does not cause permanent damage to the joints or crippling arthritis.
- Intestines: The main symptom is abdominal pain, but symptoms can also include loss of appetite, diarrhea, vomiting and occasional blood in stools. Rarely, patients develop an abnormal bowel folding called intussusception, which can be serious. Intussusception is less common in adults with IgAV.
- Kidney: Half of all patients who have IgAV have kidney inflammation, but less than 1 in 10 have permanent injury to the kidneys. Inflammation of the blood vessels in the kidneys can cause blood or protein in the urine.
- Other features: Patients with IgAV can develop fever. Boys can have painful swelling of the scrotum.