By Gary M. White, MD
Henoch-Schönlein purpura (HSP) is a form of systemic vasculitis characterized by vascular wall deposits of predominately IgA typically. It typically involves the small vessels of the skin, gut and glomeruli. Associations include purpura, abdominal pain, hematuria, arthralgia and arthritis. Viral or bacterial (e.g. Streptococcus) infections, food or drugs are thought to be triggering events. It is also called IGA vasculitis.
A child, 3-10 years of age, who develops palpable purpura on the legs and buttocks, along with abdominal pain, vomiting, diarrhea, melena, hematuria, and arthralgias is characteristic of Henoch-Schönlein purpura, also known as anaphylactoid purpura. Significant knee and ankle swelling may occur. At times, edematous, urticarial, necrotic, or hemangioma-like lesions may be seen. In one study of children [BJD 2015;172;1358], the presence of lesions above the waist and clinically evident edema were both significantly associated with GI involvement. Linear purpuric lesions are common and may be induced by socks with a tight elastic band, underwear with a thin elastic band, on the wrists from a tight bracelet and from scratching [JAMA Derm 2017;153;1170].
In a study of 57 adults with IgA vasculitis, IgA glomerulonephritis was significantly associated with purpura above the waist, a recent infectious history, pyrexia and biological markers of inflammation (e.g. elevated ESR) [AD 1997;133;438]. This can be helpful in deciding if renal biopsy is warranted in a patient with abnormal urinary microscopy. Adults with HSP tend to have renal disease more often than children.
Blood tests for kidney function along with urine analysis for proteinuria or hematuria are important. Urine analysis must be followed serially during the course of the disease. Other potential complications include abdominal and pulmonary disease. In adults, infection and malignancy should be excluded as best as possible.
Most patients have abdominal pain. Other GI findings may include: nausea and vomiting, diarrhea, and hematemesis. More severe involvement can lead to intussusception, bowel infarction, ileal stricture, ileus with massive GI hemorrhage and acute appendicitis.
EULAR criteria for diagnosing HSP requires the presence of palpable purpura (mandatory), together with at least one of the following four findings: diffuse abdominal pain, acute arthritis in any joint, predominance of IgA deposition around vessels on skin or renal biopsy, and renal involvement (any hematuria and/or proteinuria).
There are no routine blood or serologic tests specific for HSP. Routine histology alone will reveal leukocytoclastic vasculitis but will not confirm the etiology. Direct immunofluorescence microscopy of skin biopsies reveals IgA and C3 in involved and uninvolved vessel walls of lesions less than 48 hours old, and will be most helpful in establishing the diagnosis of HSP in the context of other clinical criteria, but is not necessary in classic cases.
Close consultation with either the pediatrician or the primary care physician is in order. Treatment is supportive especially in children. The disease will run its course in 6-16 weeks and spontaneously remit. Adults tend to have a worse prognosis and more aggressive therapy is often employed. This may take the form of corticosteroids, azathioprine, cyclophosphamide, cyclosporine, mycophenolate mofetil, dapsone, plasmapheresis or rituximab.
If an infection is found, it should be treated. The treatment of H. pylori cleared the skin in one case. Steroids usually do not affect the renal disease, although they may be helpful for significant edema, arthritis or pain.
Relapse occurs in one-third of cases, usually within 4 months of the initial episode. Some patients with HSP can go on to develop HTN or significant renal impairment later in life. Pulmonary hemorrhage is rare, but when does occur, is often fatal [PD 1997;299]. Presenting symptoms include dyspnea, tachypnea, coughing and hemoptysis.
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