Background
Immunoglobulin A vasculitis (IgA vasculitis, IgAV) was formerly called Henoch-Schönlein purpura (HSP).
Pathophysiology: In IgA vasculitis, IgA immune complexes are deposited in small vessels. When that happens in the skin, we see petechiae and palpable purpura. When immune complexes occur in small vessels of the intestinal wall, we see GI complications (including GI hemorrhage). If the immune complexes affect the renal mesangium, it may produce mild proliferative to severe crescentic glomerulonephritis (AFP 2009).
IgA vasculitis is more common in children under the age of 10. In fact, is the most common systemic vasculitis of childhood. It still occurs in adults, quite frequently. The clinical triad of purpura, abdominal pain, and arthritis is classic.
Diagnosis
Clinical manifestations. IgAV is characterized by a tetrad of clinical manifestations: 1) Palpable purpura without thrombocytopenia and coagulopathy; 2) Abdominal Pain; 3) Renal disease; 4) Arthralgia and/or arthritis
Complications: Orchitis with testicular swelling occurs in 35% of men with IgA Vasculitis. Other complications of IgA Vasculitis are abdominal pain, arthritis, and renal insufficiency. ESRD = The most common serious complication
The purpuric rash is classically seen on the waist and extends to the legs, sparing the proximal trunk and arms.
“A normal platelet count differentiates IgA Vasculitis from thrombocytopenic purpura (AFP 1998).
In IgA vasculitis, “platelet count may be elevated; low platelet levels suggest thrombocytopenic purpura” Medscape.
“The presence of thrombocytopenia or a coagulopathy largely excludes the diagnosis of IgAV (HSP)” (up to date)
Abdominal ultrasonography in patients with severe abdominal pain.
Treatment
Supportive is the main treatment. Almost 95% of children with HSP spontaneously improve.
Acetaminophen for arthritic pain. Avoid NSAIDs in patients with abd. pain or known renal involvement. They aggravate these conditions.
Relative rest and elevation of affected extremities – May improve purpura.
Prednisone for renal involvement or severe extrarenal symptoms.
Refer/consult nephrology if sig. renal involvement.
If a bacterial infection, like Strep pharyngitis, is identified as the cause of HSP, treat the infection.
Hospitalize for dehydration, poor pain control, and inability to adequately follow outpatient (2/2 to the social situation).
Renal Biopsy if severe renal involvement to confirm the diagnosis and guide therapy.
In patients with severe renal involvement, consider aggressive therapy which includes: High dose steroids + adjunctive immunosuppressant (e.g., azathioprine, cyclophosphamide, IV IG) OR plasmapheresis.
Treat HTN with CCB like Amlodipine.
Reference / Further Reading
J Clin Lab Anal. 2016 Jan;30(1):71-4. https://www.ncbi.nlm.nih.gov/pubmed/25385472
Am Fam Physician 2009;80(7):697-704.
Am Fam Physician. 1998 Aug 1;58(2):405-408.
Cochrane Database Syst Rev 2009;(3):CD005128. Interventions for preventing and treating kidney disease in Henoch-Schönlein purpura (HSP).
Am Fam Physician 2009;80(7):697-704. Henoch-Schönlein purpura.
Case Reports in Medicine. 2016;2016:7890379. Henoch Schonlein Purpura as a Cause of Renal Failure in an Adult.
https://www.uptodate.com/contents/iga-vasculitis-henoch-schonlein-purpura-clinical-manifestations-and-diagnosis