May also be called: Allergic Purpura, Anaphylactoid Purpura

Henoch-Schönlein purpura (HEH-nok SHOON-line PURR-puh-ruh), or HSP, is a condition in which the small arterial vessels (capillaries) in the skin, kidneys, and intestinal tract become swollen and leak. It can occur at any age but is usually seen in children, more often boys than girls.

More to Know

Although no one really knows what causes HSP, doctors do know that it occurs when the body's immune system doesn't function as it should. HSP often happens after a bacterial or viral upper respiratory infection. Other possible triggers include certain medicines, insect bites, cold weather, and vaccinations.

Signs and symptoms of HSP include a raised, reddish-purple rash, fever, stomach pain, bloody stools, blood in urine, and joint pain. HSP also can cause mild to severe kidney problems, so it’s important to see a doctor if you suspect Henoch-Schölein purpura.

With bed rest, increased fluid intake, and pain relievers, most people with HSP will see an improvement in their condition within a month. It is not unusual, however, to have mild recurrences.

Keep in Mind

Most people will recover fully from Henoch-Schölein purpura with no lingering effects. People whose kidneys are affected, however, will need to work with their doctor to prevent serious and even life-threatening complications.

All A to Z dictionary entries are regularly reviewed by KidsHealth medical experts.