About Henoch-Schonlein Purpura (HSP) In Children

What Is HSP?
Henoch-Schonlein purpura (HSP or anaphylactoid purpura) is a form of blood vessel inflammation or “vasculitis”. Each of the forms of vasculitis tends to involve certain characteristic blood vessels, often of different sizes. HSP affects the small arterial vessels and capillaries in the skin, intestinal tract, and sometimes the kidneys. HSP results in skin rash, most prominent over the buttocks and behind the lower extremities associated with joint inflammation (arthritis), and cramping pain in the abdomen. Henoch and Schonlein were two Europeans who first described this disorder in the 19th century. The word purpura comes from the Latin for “purple”.

What Is Vasculitis?
Vasculitis is a general term that refers to the inflammation of arteries, or blood vessels.

What Are The Symptoms?
Classically HSP causes skin rash, pain in the abdomen, and arthritis. Patients with HSP can develop fever. Boys can develop painful scrotal swelling. Symptoms usually last about a month, but may occur for 2 - 12 weeks. Recurrences are not frequent but do occur. Skin: purple, bruised rash on legs, buttocks or elsewhere. This is caused by red blood cells that leak out of the damaged blood vessels. The rash may be raised and/or itchy. Joints: painful, brief swelling. The joints most frequently affected with pain and swelling are the ankles and the knees. Usually this only lasts from 1-3 days in the individual joints.

The inflammation does not cause crippling arthritis. Sometimes the feet, and/or hands will become “puffy”, due to fluid leakage. This can also occur around the eyes, or in the scalp. Intestines: mostly abdominal pain, but can also include loss of appetite, diarrhea, vomiting and occasional blood in stools. Rarely, patients develop an abnormal bowel folding called intussusception. Kidney: 50% of patients have kidney inflammation, but less than 1 in 10 have permanent injury to the kidneys. Inflammation in the kidneys can cause blood or protein in the urine.

What Causes HSP?
HSP frequently follows a relatively minor infection of the throat or breathing passages (strep throat is one example). HSP represents an unusual reaction of the body's immune system in response to this infection (either bacteria or virus). HSP occurs throughout the year. Some studies have shown an increase in cases during the fall and winter months.

Who Is Affected By HSP?
HSP is the most common acute vasculitis affecting children, with an incidence of approximately 10 cases per 100,000 children, per year. Although the syndrome is usually seen in children, people of any age may be affected. It is more common in boys than in girls.

How Is HSP Diagnosed?
The diagnosis of HSP can be delayed, since the symptoms and physical findings may occur over a number of days, and sometimes do not seem connected. A history of moderate fevers, unexplained abdominal pains, joint pains (arthralgias), unusual areas of swelling, and sometimes raised, large “welts” may all occur. A tiny “dot-like” red rash may come and go, with the areas spreading, turning brown or even bruise-like. The rash is “gravity” and pressure dependent, and thus is most frequent on the lower legs and arms, on the buttocks, or other areas of increased pressure. Increased irritability is common.

Physical examination may reveal rash, joint swelling, limp, irritability, or abdominal discomfort, and these can change over the course of a day.   X-rays may show swelling of the lining of the intestines, or of the joints. Microscopic analyses may show blood in the urine and/or stool, some children are anemic, and many have blood test evidence of inflammation. A skin biopsy (usually not needed to diagnose) often shows vasculitis. Laboratory tests to rule out other diagnoses are often done.

How Is HSP Treated?
While HSP is generally a mild illness that resolves spontaneously, it can occasionally cause serious problems in the kidneys and bowels. The rash can be very prominent. The treatment of HSP is directed toward the most significant areas of involvement. Joint pains can be relieved by Tylenol, naproxen or ibuprofen. Some patients may require cortisone medications, such as prednisone, especially those with significant abdominal pain, arthritis, or scrotal edema. Often, if the intestinal lining is swollen, oral medicines are not adequately absorbed, and brief hospitalization with intravenous treatment with steroids is needed.   This usually only lasts 2-3 days.

What Is The Outlook?
The prognosis for children with HSP is generally excellent. Nearly all have no long-term problems. The kidney is the organ with the highest risk of long-term involvement. Rarely, patients can have serious kidney damage, which usually develops slowly, and without symptoms. A very few children have recurrences of HSP some time after the first episode; this can be weeks, months, or rarely, even years later.   Research shows that HSP in adults is generally more severe than in children. Adults have more severe kidney involvement, and can require more aggressive treatment. The ultimate outcome, however, is usually very good for both adults and children.

Regular follow-up with your pediatrician or family physician is important. The most important test, when your child is otherwise well, is to get a urinalysis done every several months. After the first year, twice annually is sufficient. Recently, new approaches with older medications have been successful in treating the rare child with recurrent HSP, and even helping the rare patient with kidney disease. For the most part, children do well, are ill only once, and don’t get long-term problems.