Neonatal lupus erythematosus exacerbated by vaccination.

Neonatal lupus erythematosus (LE) is a rare immune-mediated disease caused by placental transport of maternal anti-SSA/Ro, anti-SSB/La and/or anti-U1RNP antibodies. Here, we demonstrate two cases of neonatal LE, in both of which cutaneous LE was exacerbated by inoculation. To our knowledge, cases worsening neonatal LE after administration of vaccines have not been reported. In case 1, not only exacerbation of pre-existing annular erythema but also spreading of new erythematous lesions to the trunk and extremities were induced following vaccination. Of interest, all of the lesions simultaneously improved. By contrast, in case 2, pre-existing facial erythema became prominent without spreading to other sites. The mother of case 1 had Sjögren's syndrome, whereas in case 2, the mother was diagnosed with Sjögren's syndrome on this occasion for the first time. Immunohistochemistry in case 1 revealed interleukin (IL)-17-positive cells infiltrating into the papillary dermis, and CD123-positive plasmacytoid dendritic cells in the papillary dermis and the deep reticular dermis. Both innate immune response and IL-17 mediated inflammation following vaccination are speculated as a possible mechanism of the deterioration of LE lesions in our juvenile cases. Caution is necessary since neonatal LE can be worsened following vaccination.