Henoch-Schönlein purpura (HSP), also called immunoglobulin A vasculitis (IgAV), is the most common systemic vasculitis of childhood. (See 'Introduction' above.)
●HSP (IgAV) occurs primarily between the ages of 3 and 15 years. The annual incidence is 10 to 20 per 100,000 in children <17 years of age, with a peak incidence in children between 4 to 6 years of age. Approximately 10 percent of HSP (IgAV) cases occur in adults. (See 'Epidemiology' above.)
●The underlying cause of HSP (IgAV) is unknown. It is thought that HSP (IgAV) represents an immune-mediated vasculitis that may be triggered by a variety of antigens, including various infections and immunizations. (See'Pathogenesis' above.)
●HSP (IgAV) is a self-limited disease and is characterized by a tetrad of clinical manifestations that vary in their occurrence and order of presentation (see 'Clinical manifestations in children' above):
•Palpable purpura without thrombocytopenia and coagulopathy
•Arthralgia and/or arthritis
•Abdominal pain
•Renal disease
●The diagnosis of HSP (IgAV) is usually based upon clinical manifestations of the disease. In patients with an incomplete or unusual presentation, biopsy of the affected organ (eg, skin or kidney) demonstrating predominantly immunoglobulin A (IgA) deposition supports the diagnosis of HSP (IgAV). (See 'Diagnosis' above.)
●The diagnosis is more difficult if there is an incomplete presentation of HSP (IgAV) or if the skin manifestations are absent at disease onset. In these circumstances, other causes for purpura, arthritis, abdominal pain, and renal disease must be considered. (See 'Differential diagnosis' above.)
●There are no diagnostic tests for HSP (IgAV). Patients in whom the diagnosis is at all in doubt should have a complete blood count, prothrombin time, and urinalysis. The presence of thrombocytopenia or a coagulopathy largely excludes the diagnosis of HSP (IgAV). A serum creatinine level should be obtained in children with hypertension or an abnormal urinalysis. Serum creatinine should be assayed in all adult patients with HSP (IgAV) because of the increased risk of significant renal disease. (See 'Laboratory tests' above and 'Renal studies' above.)
●Abdominal ultrasonography is indicated in patients with severe abdominal pain. It can detect increased bowel wall thickness, hematomas, peritoneal fluid, and intussusception. Contrast studies may miss intussusception in patients with HSP (IgAV). (See 'Imaging studies' above.)
Leukocytoclastic vasculitis histology
Leukocytoclastic vasculitis involving the dermal papillae capillaries and venules (arrow), a finding that probably reflects an Arthus type III immune complex reaction.
Courtesy of Cynthia Magro, MD.
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Leukocytoclastic vasculitis histology
Skin biopsy from a patient with leukocytoclastic vasculitis showing striking mural fibrin deposition in a postcapillary venule and a concomitant angiocentric mixed neutrophilic and lymphocytic infiltrate. This pattern can be seen in a variety of disorders including hypersensitivity vasculitis, systemic lupus erythematosus, rheumatoid arthritis, mixed connective tissue disease, Sjögren's syndrome, Behçet's syndrome, and relapsing polychondritis.
Courtesy of Cynthia Magro, MD.
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Immunofluorescence microscopy showing mesangial immunoglobulin A (IgA) deposits
Immunofluorescence microscopy demonstrating large, globular mesangial IgA deposits that are diagnostic of IgA nephropathy or Henoch-Schönlein purpura (IgA vasculitis). Note that the capillary walls are not outlined since the deposits are primarily limited to the mesangium.
Courtesy of Helmut Rennke, MD.
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Skin lesions in Henoch-Schönlein purpura (IgA vasculitis)
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Skin manifestations of Henoch-Schönlein purpura (IgA vasculitis)
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Localized subcutaneous edema in Henoch-Schönlein purpura
Note swelling in the lower extremities, particularly the right leg/foot.
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Dorsal hand edema and purpuric rash in a child with immunoglobulin A vasculitis (Henoch-Schönlein purpura)
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Acute hemorrhagic edema of infancy
Note purpura, ecchymosis, and inflammatory edema of the extremities.
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Henoch-Schönlein purpura (immunoglobulin A vasculitis): Management
Most patients with Henoch-Schönlein purpura (HSP), also called IgA vasculitis (IgAV), may be cared for in the ambulatory setting with therapy directed toward adequate oral hydration, bed rest, and symptomatic relief of joint and abdominal pain.
●In patients with joint and/or abdominal pain, we suggest the use of a nonsteroidal antiinflammatory agent (Grade 2C). We typically use naproxen (10 to 20 mg/kg divided into two doses per day). A maximum dose of naproxen of 1500 mg per day may be used for a few days provided that adequate hydration is maintained. If more than a week of nonsteroidal antiinflammatory drug (NSAID) treatment is necessary, the dose of naproxen should not exceed 1000 mg per day.
●In patients with severe abdominal pain that interferes with their oral intake and who fail to respond to a nonsteroidal antiinflammatory agent, we suggest the use of systemic glucocorticoids (Grade 2C). We use oralprednisone (1 to 2 mg/kg per day) for children or adults, with a maximum dose of 60 to 80 mg per day, or equivalent doses of intravenous methylprednisolone (0.8 to 1.6 mg/kg per day, maximum dose of 64 mg per day). Patients who are treated with glucocorticoids for severe abdominal pain require particular vigilance, since these medications can obscure the signs and symptoms of abdominal catastrophes associated with HSP (IgAV). Glucocorticoids should be tapered slowly, by no more than 25 percent per week, lest symptoms relapse.
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Hospitalization is indicated in patients who fail to maintain oral hydration and require the administration of intravenous fluids. Inpatient management may also be necessary to manage patients who have significant gastrointestinal bleeding, severe abdominal pain, changes in mental status, severe joint involvement limiting ambulation and/or self-care, or evidence of significant renal disease
●We do not recommend glucocorticoid administration to prevent renal or gastrointestinal complications (Grade 1B).
●Although prognosis is excellent in children with HSP (IgAV), a small minority of patients (<1 percent) develops long-term complications, primarily renal disease. In adults, the risk of significant renal disease is increased. At present, there is no known therapeutic regimen to forestall development of renal involvement. Therapy for optimal control of HSP (IgAV)-related nephritis or nephrosis is discussed elsewhere.
●Patients who have developed HSP (IgAV) should be seen in follow-up with screening for urinary abnormalities and elevated blood pressure to identify patients with significant and potentially progressive renal involvement. (See 'Follow-up' above.)
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