A small skin rash, called purpura, is a hallmark symptom of the most common form of vasculitis in children. Henoch-Schönlein purpura (HSP), named for German doctors, Eduard Henoch and Johann Schönlein, is seen most often in kids aged 2-11, with twice as many cases in boys than girls.
In HSP, capillaries become irritated, causing them to swell. This swelling, or vasculitis, usually occurs in kidneys, intestines, or the skin. When the capillaries in the skin swell, they often leak, causing the purpura rash associated with HSP. Vessels in the intestines and kidneys also can swell and leak.
The Mayo Clinic explained that this condition occurs when the immune system reacts to a protein, known as immunoglobulin A (IgA). HSP usually strikes after a child has a bacterial or viral infection in the sinuses, lungs or throat. Some medicines, food, insect bites, or vaccines can also cause it.
Since a rash accompanies nearly all HSP cases, doctors can usually diagnose from the purpura rash or another one, made up of small red dots known as petechiae. The rash occurs on the buttocks and legs, but can also show up on elbows, trunk, face, or arms.
Another common symptom of HSP is painful swelling in the larger joints -- knees, elbows, ankles -- but feet and hands can also hurt. About a week after the rash appears, a child may have stomach aches, accompanied by vomiting or diarrhea.
Since HSP can cause complications to the kidneys or bowels, the Mayo Clinic recommends you call your child’s doctor if you spot the HSP rash on your child.
Many young children with HSP recover in about a month, with no specific treatment. However, according to the KidsHealth website, about half of all children who develop this condition also experience kidney complications.
If this is the case, your health care provider will recommend your child has regular appointments over the next few months to check on kidney function. If kidney damage is a concern, your child may be referred to a kidney specialist.
About a third of children with HSP will experience symptoms again, a few months later.