Henoch-Schonlein purpura (HSP) is a disease involving inflammation of small blood vessels. It most commonly occurs in children. The inflammation causes blood vessels in the skin, intestines, kidneys, and joints to start leaking. The main symptom is a rash with numerous small bruises, which have a raised appearance, over the legs or buttocks.
Although HSP can affect people at any age, most cases occur in children between the ages of 2 and 11. It is more common in boys than girls. Adults with HSP are more likely to have more severe disease compared to children.
HSP usually ends after four to six weeks -- sometimes with recurrence of symptoms over this period, but with no long-term consequences. If organs such as the kidneys and intestines are affected, treatment is often needed and it is important to have regular follow-up to prevent serious complications.
Causes and Risk Factors for Henoch-Schonlein Purpura
The exact cause of HSP is not known. The body's immune system is believed to play a role in targeting the blood vessels involved. An abnormal immune response to an infection may be a factor in many cases. Approximately two-thirds of the cases of HSP occur days after symptoms of an upper respiratory tract infection develop.
Some cases of HSP have been linked to vaccinations for typhoid, cholera, yellow fever, measles, or hepatitis B; foods, drugs, chemicals, and insect bites. Some experts also say that HSP is associated with the colder weather of fall and winter.
Symptoms of Henoch-Schonlein Purpura
The classic symptoms of HSP are rash, joint pain and swelling, abdominal pain, and/or related kidney disease, including blood in urine. Before these symptoms begin, patients may have two to three weeks of fever, headache, and muscular aches and pains. Rarely, other organs, such as the brain, heart, or lungs, may be affected.
Here are some key details about the symptoms of HSP:
Rash. The rash usually appears in all patients with HSP. The initial appearance may resemble hives, with small red spots or bumps on the lower legs, buttocks, knees, and elbows. But these change to appear more like bruises. The rash usually affects both sides of the body equally and does not turn pale on pressing.