Henoch-Sch?nlein Purpura (HSP)

About Henoch-Sch?nlein Purpura

Henoch-Sch?nlein purpura (pronounced: heh-nok shoon-line purr-puh-ruh) — usually just called HSP — is a condition that causes small blood vessels, or capillaries, to become swollen and irritated. This inflammation, called vasculitis, usually occurs in the skin, intestines, and kidneys. Inflamed blood vessels in the skin can leak red blood cells, causing a characteristic rash called purpura. Vessels in the intestines and kidneys also can swell and leak.

The disorder was named after two German physicians, Eduard Henoch and Johann Sch?nlein, who first described the disease in the 1800s. Sometimes it's also called allergic purpura or anaphylactoid purpura.

HSP occurs much more often in kids than in adults, usually happening between ages 2 and 11. It is one of the most common forms of vasculitis in children, and boys get it about twice as often as girls.

Causes

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. A protein called immunoglobulin A (IgA) is deposited into the blood vessels and sets off an immune reaction.

In most cases, HSP occurs after a child has had a bacterial or viral infection of the upper respiratory tract (sinuses, throat, or lungs). But certain medicines, food reactions, insect bites, and vaccinations also may cause it.

HSP cannot be passed from one person to another.

Signs and Symptoms

Common signs and symptoms of HSP include:

• purpura, the raised, reddish purple rash
• joint pain and inflammation
• stomach pain
• blood in the urine or stool, or kidney problems
• fever
• headache

The rash occurs in almost all cases and is usually what helps doctors diagnose HSP. There also may be pinpoint red dots (called petechiae), bruises, or sometimes blisters. The rash usually occurs on the legs and buttocks, but can also appear on other parts of the body, such as the elbows, arms, face, and trunk.

Most kids with HSP also have joint pain and swelling. These symptoms can happen before the rash appears. They most commonly affect large joints, such as the knees, ankles, and elbows, but the hands and feet can be affected.

Stomach pain usually starts a week after the rash appears. Pain is intermittent and can be accompanied by nausea, vomiting, or diarrhea. Some kids will have blood in the stool (caused by leaky blood vessels), but it may not be visible.

HSP can affect the kidneys. Small amounts of blood or protein might be found in the urine, which occasionally can be bloody.

Diagnosis

When the characteristic rash on the legs and buttocks is present, especially if accompanied by abdominal or joint pain, doctors can easily diagnose HSP. A diagnosis may be more difficult if joint pain or abdominal symptoms are present before the rash appears, or if symptoms take several weeks to show up. To help make the diagnosis, the doctor may recommend a skin biopsy.

The doctor also may request routine blood tests to look for signs of infections, anemia, or kidney disease. If abdominal pain is severe, imaging tests (like X-rays or ultrasound) may be needed. A stool sample can check for blood in the stool and urine.

Up to half of kids who develop HSP will have complications with their kidneys, so the doctor will probably check kidney function over several months. If the doctor suspects that HSP has caused kidney damage, your child may need to see a kidney doctor (nephrologist).

Treatment

Symptoms of HSP usually last for about a month. Most of the time, it goes away on its own without treatment. To help your child feel better, the doctor may recommend certain medications, such as:

• antibiotics to treat the causative infection, if applicable
• painkillers (such as acetaminophen)
• anti-inflammatory medicines (such as ibuprofen) to relieve joint pain and inflammation
• corticosteroids (such as prednisone) for severe abdominal pain or kidney disease

Also, the doctor may tell you to stop giving your child certain medications if there's a chance that they caused the HSP.

While at home, try to keep your child as comfortable as possible. Be sure your child gets plenty of rest and drinks fluids. If your child stops eating or drinking, or develops severe abdominal pain or kidney problems, hospitalization might be necessary.

Outlook

Most children with HSP fully recover within a month and have no long-term problems. Kids whose kidneys are affected will need to see a doctor for regular checkups to monitor kidney function.

About one-third of those who have HSP get it again, usually a few months after the first episode. This (along with chronic kidney problems) is more common in older kids and adults. If HSP does come back, it's usually less severe than the initial episode.

Reviewed by: Mary L. Gavin, MD
Date reviewed: June 2009