IgA vasculitis, or Henoch-Schönlein purpura, classically presents as a tetrad of palpable purpura, acute-onset arthritis or arthralgia, abdominal pain, and renal disease with proteinuria or hematuria.30 Skin involvement is seen in almost all cases and is essential for diagnosis of IgA vasculitis. The initial dermatosis may be pruritic and present as an erythematous macular or urticarial wheal that evolves into petechiae, along with palpable purpura that is most frequently located on the legs or buttocks (Figure 7).30-34
IgA vasculitis is an immune-mediated small vessel vasculitis with deposition of IgA in the small vessels. The underlying cause remains unknown, though infection, dietary allergens, drugs, vaccinations, and chemical triggers have been recognized in literature.32,35,36 IgA vasculitis is largely a pediatric diagnosis, with 90% of affected individuals younger than 10 years worldwide.37 In the pediatric population, the incidence has been reported to be 3 to 26.7 cases per 100,000 children.32
Diagnosis is based on the clinical presentation and histopathology.30 On direct immunofluorescence, IgA deposition is seen in the vessel walls.35 Laboratory testing is not diagnostic, but urinalysis is mandatory to identify involvement of renal vasculature. Imaging studies may be used in patients with abdominal symptoms, as an ultrasound can be used to visualize bowel structure and abnormalities such as intussusception.33
The majority of cases of IgA vasculitis recover spontaneously, with patients requiring hospital admission based on severity of symptoms.30 The primary approach to management involves providing supportive care including hydration, adequate rest, and symptomatic pain relief of the joints and abdomen with oral analgesics. Systemic corticosteroids or steroid-sparing agents such as dapsone or colchicine can be used to treat cutaneous manifestations in addition to severe pain symptoms.30,31 Patients with IgA vasculitis must be monitored for proteinuria or hematuria to assess the extent of renal involvement. Although much more common in adults, long-term renal impairment can result from childhood cases of IgA vasculitis.34
Pediatric dermatology emergencies can be difficult to detect and accurately diagnose. Many of these diseases are potential emergencies that that may result in delayed treatment and considerable morbidity and mortality if missed. Clinicians should be aware that timely recognition and diagnosis, along with possible referral to pediatric dermatology, are essential to avoid complications.