Henoch-Schonlein purpura (HSP) is a rare inflammatory disease of the small blood vessels (capillaries) named after doctors Henoch and Schonlein who discovered it over 30 years ago.
It often follows an acute respiratory infection and may be some kind of allergic reaction to the virus. The exact cause is not fully understood although research suggests that it may be an auto-immune disease or, in some rare cases, an extreme allergic reaction to certain substances (eg, food or drugs).
Who gets Henoch-Schonlein purpura?
It primarily affects young children aged from 2 to 10 years although people of any age may be affected. Boys, more than girls, are most often affected and the older the child (or adult) the more likely it is to be serious.
What are the symptoms?
* Purple spots on the skin, usually over the buttocks, lower legs and elbows
* Loss of appetite
* Cramping abdominal pain
* Joint pain
The disease can begin abruptly or different symptoms may appear gradually over several weeks. The red or purple spots which typically appear on the skin represent swollen blood vessels. These spots blanch with pressure, since pressure moves the blood along the vessel. Over time, as blood leaks from the swollen vessels, the rash changes from red to a bruised, purple colour (hence the name purpura), and the rash no longer blanches when pressed. As the bruises heal they turn to a rust colour and then fade. Each spot lasts for about a week. The rash often comes in several crops which can occur over days to several weeks. A single child may, therefore, have a rash of a variety of different colours which will eventually resolve without trace.
As well as the skin rash, which all children with HSP get, joints may be affected, particularly the knees, ankles, hips, wrists and elbows, which often become swollen, tender and painful with movement. While this can be quite debilitating, the condition usually resolves after a few days and no permanent deformity results, even in the most serious cases.
Some children may experience abdominal pain and will often vomit, sometimes vomiting blood. They may also pass bloody stools and pass blood in their urine. Kidney involvement is common in up to 60% of sufferers, although serious kidney damage is rare. Serious long-term complications most often occur due to kidney involvement. Rarely, blood vessels in the muscles, eyes, testicles, lungs, heart and brain can become inflamed, sometimes with serious consequences.
Children can die from complications such as bowel perforation, haemorrhage, seizure, stroke, etc, but this is rare. Most children recover fully.
HSP may be mild and last for just a few days. For those with moderate to severe symptoms, however, it can last for 4 to 6 weeks, with relapses occurring up to a year later after a disease free interval of several weeks.
What can be done about it?
There is no specific treatment for this disorder. Most cases resolve spontaneously without treatment. If symptoms persist, anti-inflammatory drugs, and sometimes immunosuppressive drugs, may be used to provide relief.