HSP, a vasculitic syndrome characterized by skin rash, abdominal colic, joint pain and glomerulonephritis, was first described in 1801 by Dr. William Heberden . The syndrome is mainly a disease of early childhood with most cases presenting by 10 years of age. It is uncommon in adults over the age of 20. Men are affected more than women with a ratio of 1.2:1 to 1.8:1 . A recent history of respiratory tract infection is reported in 90% of cases. Other precipitating factors, reported in the adult onset of HSP, include medications (non-steroidal anti-inflammatory drugs, angiotensin-converting enzyme inhibitors, and antibiotics such as vancomycin and cefuroxime), food allergies, vaccinations, and insect bites.
The clinical manifestations of HSP may develop over the course of days to weeks and may vary in their order of presentation; however, renal involvement usually presents late. The purpuric skin lesions are typically located on the lower extremities but may also be seen on the hands, arms, trunk, and buttocks.
Gastrointestinal disease occurs in up to 70% of patients varying from colicky abdominal pain, nausea and vomiting to intestinal hemorrhage, intussusceptions, pancreatitis and hydrops of the gall bladder. More than 30% of patients experience diffuse pain described as 'bowel angina' typically occurring after meals and accompanied by bloody diarrhea. Renal involvement is usually noted within a few days to one month after the onset of systemic symptoms. Renal manifestations occur more commonly and tend to be more severe in adults including end-stage renal disease . Urinary abnormalities are present in 25% to 50% of patients. Hematuria is the most common symptom and the earliest sign of renal involvement. Although early studies suggested that renal involvement could not be predicted from the severity of extra-renal involvement, a recent study showed that a recent infectious history, pyrexia, spread of purpura to the trunk, and biological markers of inflammation were predictive factors for renal involvement . The risk of renal involvement is also increased when HSP patients present with bloody stools  as in our patient.
Joint involvement occurs in 60% to 84% of cases and generally affects ankles and knees. In adults, involvement of the small joints is more common . Our patient did not experience active joint symptoms which is an atypical presentation.
The diagnosis of HSP is based on clinical signs and symptoms. Laboratory studies generally show a mild leukocytosis, a normal platelet count, and occasionally eosinophilia. Serum complement components are normal. IgA levels are elevated in about one-half of patients. In patients with unusual presentations, a biopsy of an affected organ (for example, skin or kidney) that demonstrates leukocytoclastic vasculitis with a predominance of IgA deposition confirms the diagnosis of HSP.
A kidney biopsy can be done to establish the diagnosis, but this invasive procedure is generally reserved for patients in whom the diagnosis is uncertain or who have more severe renal involvement such as marked proteinuria and/or impaired renal function during the acute episode. The percentage of glomeruli showing crescents is the most important prognostic finding.
The long term prognosis of HSP is almost entirely determined by the behavior of the nephritis. The short term outcome of renal disease in HSP is favorable in most patients, with complete recovery reported in 94% of children and 89% of adults . Recurrence of HSP is common, occurring in up to one-third of patients and more likely in patients with renal involvement. Among adults, the reported rates of end-stage renal disease range from 10% to 30% at 15 years.
There is no specific treatment for HSP. The majority of cases are mild and need only supportive measures. Although there is evidence suggesting that corticosteroids enhance the rate of resolution of the arthritis and abdominal pain, they do not seem to prevent recurrence of disease. Aggressive therapy with corticosteroids or cyclophosphamide has not been proven to be beneficial in reversing the renal disease except among patients with crescentic nephritis . However, some experts recommend a six-month course of corticosteroids for patients with the nephrotic syndrome and those with a reduced glomerular filtration rate. Renal transplantation can be performed in those patients who progress to end-stage renal disease.
Our patient underwent a kidney biopsy because of marked proteinuria and acute kidney injury. The biopsy showed IgA mesangioproliferative glomerulonephritis with less than 50% crescents indicating a good prognosis. He was initially treated with intravenous methylprednisolone and was transitioned to prednisone tapering orally to complete the six-months of steroid therapy. There was marked improvement of abdominal pain and gastrointestinal bleeding. Skin lesions gradually faded. Acute kidney injury and proteinuria also improved.