Leukocytoclastic vasculitis (angiitis) may follow vaccination.
Vaccines reported to cause include:
(1) COVID-19
(2) influenza
(3) HBV
(4) HPV
Mechanism: probably immune complex deposition
Clinical findings:
(1) purpuric papules which may be palpable
(2) erythematous macules
This may be a new-onset or exacerbation of existing leukocytoclastic vasculitis.
Skin biopsy may show:
(1) a perivascular inflammatory infiltrate with neutrophils and eosinophils
(2) red blood cell extravasation
(3) variable fibrinoid necrosis of vessel wall
