Pemphigus vulgaris (PV) is an acquired autoimmune bullous disease of the mucous membranes with or without skin involvement. It is typically characterized by the presence of circulating pathogenic autoantibodies (predominantly immunoglobulin [Ig]G4) against desmoglein 3 (Dsg3) with or without desmoglein 1 (Dsg1), which are cadherin family, keratinocyte cell surface adhesion molecules of the desmosome, although other antibody subtypes and autoantibodies against other antigenic targets have been described.

Neonatal PV is a transient, autoimmune, blistering and inflammatory disorder caused by passive transfer of the birthing parent's IgG antibodies. The composition of Dsg3 in neonatal skin is notably similar to adult mucosa. As such, neonates with elevated Dsg3 antibodies with or without Dsg1 antibodies can present with cutaneous findings, as opposed to findings limited to the mucosa as seen in adults. Vesicles, bullae, and erosions are typically present at birth or develop shortly after delivery, with some appearing within the first 10-15 hours of life. They typically resolve within 2-3 weeks and up to 6-12 weeks after birth, when the birthing parent's antibodies are catabolized.