What are the causes of HSP?
The causes of HSP are not fully understood. One theory is that it may develop as an immune response to an infection. In other words, the body’s infection-fighting system, the immune system, continues to attack cells after the infecting organisms are gone. For example, HSP may develop after a cold. The cold germs cause your immune system to take action. Once the immune cells have rid the body of the germ cells, they normally rest. But with HSP, the immune cells continue to attack other cells in the body. This theory is also based on the fact that, in many cases, HSP symptoms recur or worsen during upper respiratory infections. HSP has also been associated with insect bites and exposure to cold weather. Other cases have developed after a person received vaccination for typhoid, measles, cholera, hepatitis B, or yellow fever. Some foods, drugs, or other chemical toxins may trigger HSP as well. Often no cause can be found. The primary symptom of Henoch-Schönlein purpura is a rash that look
