Etiology of HSP
While the exact cause of HSP is unknown, it is believed that the body’s immune system targets the blood vessels that become inflamed. The abnormal immune response occurs after an infection. In fact, approximately two-thirds of HSP cases begin days after an upper respiratory tract infection develops. Other infections that can cause HSP include those from streptococci bacteria, herpes simplex viruses, parvovirus B19, mumps, rubella, and so on.
A few cases of HSP have been attributed to vaccinations for typhoid, cholera, measles, hepatitis B and yellow fever; foods, chemicals, drugs, and insect bites.
Some experts believe HSP is also associated with colder weather in the autumn and winter months.