Henoch Schonlein Purpura (HSP)

Simone Sher

HSP: IgA VasculitisMost common form of systemic vasculitis in

children

90% of cases occur in pediatric population, typically is self limited

Characterized by tetrad of: palpable purpura, arthralgia/arthritis, abdominal pain, renal disease

Epidemiology of HSPMost commonly occurs between ages 3-15; peak

incidence between ages 4-6Annual incidence 20 per 100,000 children <17 years oldMale predominance 1.2 to 1.8 : 1Most commonly occurs in winter, fall, and spring, rare in

summer months due to association with upper respiratory infections

Most often preceded by an infection, but vaccinations and insect bites have also been associated with development of HSP

In 1990 American College of Rheumatology established criteria. Two or more of these features >90% sensitivity and specificity for HSP

Palpable purpuraOnset before age 20Acute abdominal painBiopsy showing granulocytes in walls of arterioles or

venules

Classification of HSP

In 2005 European pediatric guidelines for HSP were created. These criteria are considered more appropriate for pediatric settings to distinguish between other processes like gastroenteritis or appendicitis. Mandatory criteria of purpura or petechiae plus one or more of the following:

Acute onset abdominal painArthritis/arthralgiasRenal involvement (proteinuria, hematuria)Leukocytoclastic vasculitis or proliferative

glomerulonephritis with predominant IgA deposition

Classification of HSP

Pathogenesis of HSP Immune mediated vasculitis due to IgA depositionAssociated with a variety of infectious and chemical

triggers but exact mechanism is unknownCharacteristic finding is leukocytoclastic vasculitis

with IgA immune complexes in affected organs. Skin biopsies of the purpuric lesions show small

vessels of the papillar dermis, usually post capillary venules, to have inflammatory infiltrate

Immunofluorescence shows IgA, C3, and fibrin in the walls of vessels of affected organs

Clinical Manifestations of HSP

Develop over the course of weeks and can vary in order of presentation.

Purpuric skin rash and joint pain are most common presenting symptoms

Skin: rash often begins with erythematous, macular, or urticarial wheals. The wheals then coalesce and evolve into the typical ecchymoses, petechiae, and palpable purpura. Typically located in pressure dependent areas such as the lower extremities.

Localized subcutaneous edema can also be seen in periorbital and dependent areas

Arthritis/ArthralgiaOccurs in 84% of patientsUsually transient, migratory, oligoarticular (1-4

joints), and non-deforming. Usually effects lower extremities and can have periarticular swelling and tenderness, but joint will not have effusion, be red or warm.

Does not cause any permanent joint damage or sequelae

GIOccur in about half of patients. Can be mild

(nausea, vomiting, abdominal pain, ileus) to severe (gi hemorrhage, intussusception, perforation)

Pain is caused by submucosal bowel hemorrhage and edema. Purpuric lesions can be seen on endoscopy

Edema and hemorrhage can act as a pathologic lead point for intussusception. 60% is in small bowel, in contrast to idiopathic intussusception which is typically ileocolic

Renal DiseaseMore common in older children and adultsMost common presentation is hematuria, with or

without red cell casts and proteinuriaNephrotic range proteinuria, elevated serum

creatinine, and/or hypertension are present in a minority of patients

Renal biopsy is identical to IgA nephropathy

Other more rarely affected organs

Scrotum (scrotal pain/swelling)Nervous system (headaches, seizures,

neuropathy)Respiratory Tract (impaired lung diffusion

capacity and interstitial changes)Eyes (keratitis, uveitis)

DiagnosisTypically a clinical diagnosis. With unusual

presentation can do biopsy of effected organ which would show leukocytoclastic vasculitis with a predominance of IgA deposition

Lab findings (CBC, chem panel, UA) typically non-specific. Patients may have leukocytosis and elevated ESR.

Hypocomplementemia found in a large percentage of patients

Treatment Most patients recover spontaneously in ambulatory setting with

supportive care of rest, hydration, and pain relief with tylenol or NSAIDs

Patients with severe abdominal pain that interferes with oral intake that fails treatment with NSAIDs (after complications such as intussusception are ruled out) can be given prednisone

Hospitalization is indicated in patients who fail to maintain oral hydration, have significant gastrointestinal bleeding, severe abdominal pain, changes in mental status, severe joint involvement limiting ambulation, or evidence of significant renal disease (elevated creatinine, hypertension, or proteinuria)

Prognosis is excellent, however a small minority of patients (<1 percent) develop long-term complications, primarily renal disease 2/3 of children will not recur. 1/3 will recur at least once, typically

within 4 months. Each subsequent recurrence is typically milder and shorter in duration