Henoch-Schonlein purpura (HSP) is a form of vasculitis, a condition in which some of the small blood vessels in the body become inflamed. HSP occurs when immunoglobulin A (IgA), a protein in the body that typically fights off infections, attacks the blood vessels instead. For this reason, HSP is sometimes also called IgA vasculitis. HSP affects people of all ages, but is most common in young children, and it often occurs after an infection such as a cold or strep throat. Although children may be sick before getting HSP, HSP itself is not contagious.
HSP typically affects the blood vessels in the skin, gasterointestinal (GI) tract and kidneys. One of the first symptoms is a raised purple rash that looks like bruises (purpura). It can most commonly be seen on the legs and buttocks, but can sometimes affect the arms, face and trunk as well. Some children develop GI symptoms such as stomach pain, nausea, vomiting, diarrhea or bloody stool. Children whose kidneys are affected may have visible blood in their urine or they may have low levels of protein or blood or urine that can only be detected with laboratory testing. Joint pain and swelling (arthritis) is also common. Children may have some or all of the above symptoms, and these may occur all at once, or spread out over several weeks.
Doctors may suspect HSP in a child who has the characteristic rash, as well as joint pain and GI issues. Though there is no single lab test that confirms the diagnosis, blood work may be helpful to rule out other causes and to look for signs of infection. All children with HSP should have urine testing for blood and protein to see if there is any kidney involvement. Children with severe abdominal pain may require stool studies and imaging such as an ultrasound, X-ray or CT scan.
In most children with HSP, symptoms go away without any treatment, though over the counter medicines such as tylenol or motrin may help with the joint pain. Children with severe GI symptoms, kidney involvement, or recurrent HSP may require steroids or other immunosuppressive medication. If HSP was triggered by a bacterial infection, antibiotics may be prescribed.