The symptoms usually begin suddenly and may include:
- Bloody stools
- Joint pain
- Loss of appetite
- Painful menstruation
- Red or purple spots on the skin. These usually appear on the buttocks, lower legs and elbows
- Stomach cramps, nausea, vomiting or diarrhea
The disease can affect the joints, kidneys, digestive system and - in rare cases - the brain and spinal cord. There are different forms of the disease, which affect different parts of the body. For example:
- Schönlein's purpura affects the skin and joints but not the digestive system
- Henoch's purpura causes spots on the skin and severe abdominal problems. Persons with this form of the disease do not have joint symptoms.
Causes and Risk Factors
The cause is not yet known. Research indicates that it may a condition in which the body's defense systems attack the body itself (an autoimmune disorder). It may be an abnormal response to a virus or an infection. In rare cases, it may be caused by an extreme allergic reaction to a food, a drug such as penicillin, exposure to cold, insect bites or other irritating substances.
Some researchers believe the disease is more common in the spring, fall and winter than in other times of the year.
The syndrome is seen more often in children, but people of any age can develop Henoch-Schönlein purpura. About half of the children who develop the condition had an infection of the lungs and upper respiratory tract before the symptoms developed. It is more common in boys than in girls.