There is a cutaneous variant with minimal systemic changes. Occasionally periosteal new bone formation may occur under these skin lesions. The disease can occur in association with Crohn's disase, Kawasaki's syndrome, rheumatoid arthritis, and angioimmunoblastic lymphadenopathy. It is thought to arise from circulating immune complexes. There is a well documented association with Hepatitis B surface antigen positivity as well as a preceeding Streptococcal infection.
Death is usually secondary to vasculitis occurring within the kidneys or gastrointestinal tract.
Direct immunofluorescence may show C3 and IgM within the walls. Sternberg S. Diagnostic Surgical Pathology. Lipincott Williams and Wilkins 1999.