Urticarial vasculitis secondary to H1N1 vaccination.

© 2010 The Authors. doi: 10.2340/00015555-0950 Journal Compilation © 2010 Acta Dermato-Venereologica. ISSN 0001-5555 The first case of a novel influenza infection was reported in Mexico in April 2009. The swH1N1 influenza A strain, which is an amalgamation of swine, bird and human influenza (1), has subsequently spread across the world, creating the first influenza pandemic since 1968. H1N1 vaccines are available as a live, attenuated monovalent vaccine (LAMV) for intranasal administration and as monovalent, inactivated, split-virus or subunit vaccines (MIV) for injection. The MIV is available with and without adjuvants. Outcomes of studies completed to date suggest that pandemic vaccines are as safe as seasonal influenza vaccines. Side-effects reported so far are similar to those observed with seasonal influenza vaccines. Urticarial vasculitis following H1N1 vaccination has not been reported previously.