Leukocytoclastic vasculitis induced by medications displaying colocalizing lesional deposits for CD15, myeloperoxidase and HLA-DPDQDR: A Yin and Yang?

Leukocytoclastic vasculitis is an inflammatory disease of small blood vessels; circulating immune complexes are part of the disease. A 57-year-old female presented with a sudden appearance of palpable purpura with petechial hemorrhages on the lower limbs after taking multiple medications. Skin biopsies were stained for H&E, direct immunofluorescence (DIF) and immunohistochemistry (IHC). The DIF revealed strong staining with multiple immunoglobulins and other markers in small dermal blood vessels, including those around skin appendices The IHC was positive for myeloperoxidase. CD15, myeloperoxidase and HLA-DPDQDR on the upper dermal blood vessels, as well as on inflammatory cells and debris around the vessels. These findings have not been previously documented and may indicate that circulating immune complexes activate the neutrophils. [ABSTRACT FROM AUTHOR]