Growing Spots: Henoch-Schonlein Purpura

• Henoch-Schonlein Purpura (HSP)
• Thrombotic Thrombocytopenic Purpura (TTP)
• Immune Thrombocytopenic Purpura (ITP)
• Juvenile Idiopathic Arthritis (JIA)/Juvenile Rheumatoid Arthritis (JRA)
• Meningococcemia
• Bacterial Endocarditis
• Diffuse Intravascular Coagulation (DIC)

• CBC, CMP, coagulation profile, urinalysis
• ESR/CRP, +/- IgA level
• Consider rheumatologic tests including C3/C4 levels, dsDNA, and ANA

HSP is a small vessel vasculitis, closely related to IgA vasculitis, and it is the most common vasculitis in childhood. Its pathogenesis is related to hypersensitivity, IgA deposition, and neutrophilic damage to the vasculature. HSP can affect the small blood vessels of the skin, GI tract, joints, kidneys, and CNS.

It is very similar to a leukocytoclastic vasculitis, which is a small vessel vasculitis that can affect many areas of the body. There are many causes for leukocytoclastic vasculitis, including medications, malignancy, collagen-vascular diseases, and idiopathic causes. What is important to remember, is they both commonly present with palpable purpura.

More than 75% of those affected are less than 10 years old, and the peak age of incidence is four to six years. Males are affected more than females in a 2:1 ratio. Of note, HSP can also affect adults and is often more severe when it does so.

The most common hallmark of HSP is palpable, cutaneous purpura, most often affecting the legs and buttocks. The classic HSP presentation involves palpable purpura and joint pain in a child, with abdominal pain or hematuria. It can also present with vomiting, bloody stools, and scrotal edema. The rash usually lasts about 3 weeks.

• ITP/TTP/HUS: These present with purpura (usually considered non-palpable) but also present with thrombocytopenia, whereas the platelet count in HSP is generally normal to elevated.
• DIC: Platelet count is reduced in DIC, and again usually normal to elevated in HSP. In addition, DIC is more common in the setting of severe sepsis or trauma, where HSP does not typically present with clinical deterioration.
• Bacterial Endocarditis/Meningococcemia: A purpuric rash can be present in these disorders as well, often resulting from DIC; however, a careful history and physical can exclude these etiologies based on clinical features. You can always refer to Dr. Alfonso’s post on Duke Criteria for endocarditis for a refresher: So Bored I Began to Murmur
• Systemic Vasculitis: Disorders like Wegener’s glomerulonephritis, microscopic polyangitis, or mixed cyroglobulinemia can present with renal damage, glomerulonephritis, and skin lesions. While this might not be figured out in the ED, it’s important to consider the whole clinical picture. Labwork such as C3/C4 levels, cyroglobulin levels, and rheumatoid factor may be considered to start your patient’s workup.
• Rheumatologic Disorders: It’s important to consider SLE, JIA/JRA, and other rheumatologic diseases, as it may help with treatment decisions and future follow-up/management. Consider concurrent symptoms, previous occurrences, and labwork such as C3/C4, ANA and ds-DNA to help form a better clinical picture.
• Acute Abdomen: Given its GI involvement, HSP may mimic an abdominal emergency. Although rare, complications like intussusception can be seen in 2-6% of cases. Also rare are perforation and bowel ischemia. Consider the whole clinical picture, and remember most abdominal pain in HSP is benign. Consider further imaging such as ultrasound if indicated.

The mainstay of HSP treatment is supportive. This means ensuring the patient, or child, is well hydrated with their pain controlled and watching out for abdominal and renal complications – worsening pain, hematuria, proteinuria, and acute renal failure. If you suspect any drug-related causes, discontinue those agents. Acetaminophen or NSAIDS can be used for minor complications like mild abdominal pain, arthralgia, or swelling, but avoid NSAIDS in cases with renal complications.

Renal involvement is the most serious and common long-term complication, and monitoring for development of hypertension is needed to ensure adequate treatment and consultation if indicated. Urinalysis and blood pressure monitoring should be continued for up to 6 months after presentation, even if essentially normal during the first visit.

In self-limiting cases of HSP, the child can often be discharged home with close follow-up with instructions for adequate hydration and pain control. Although there are no real criteria, consider admission in patients with severe abdominal pain or vomiting, acute renal complications and need for monitoring, or if the diagnosis is unclear.

The use of corticosteroids and other immunosuppressive therapy for HSP is controversial and debated. A meta-analysis done by Weiss et. Al in 2007⁽¹⁾ showed a reduction in time to resolution of abdominal pain and a significant reduction in the odds of developing chronic renal disease with early use. However, another study has shown no significant reduction in delayed nephritis in children with HSP treated with corticosteroids.⁽²⁾ The lack of RCTs makes it difficult to offer a clear clinical recommendation.

While the “when and how” to use corticosteroids remains unclear, the general opinion seems to be to use corticosteroids if complications are present such as renal disease, severe abdominal pain, intussusception, or bowel perforation.^{(3, 4)}