Case report: Case of pemphigus vulgaris in oral mucosa showing an extension to the body surface with recurrent varicella

A 60-year-old female with pemphigus vulgaris limited to the oral mucosa being treated with prednisolone showed a widespread extension of lesions to the body and extremities over a short period. The eruptions on the body began as small vesicles that looked unlike the blisters of pemphigus vulgaris, and increased to large blisters and erosions compatible with pemphigus. A smear test of the vesicles in the early stage demonstrated multinucleated acantholytic keratinocytes, which were positively stained with an antivaricella zoster virus (VZV) antibody by the immunoperoxidase method. The widespread eruptions improved immediately after 5 days' administration of valaciclovir hydrochloride tablets and increased dosage of prednisolone, leaving tiny shallow scars and pigmentation. The anti-VZV antibody in the serum was not elevated, and there were no zosteriform eruptions noted during the course. We thought that widespread extension of the pemphigus vulgaris in this case was provoked by recurrent varicella, in a similar fashion to Koebner phenomenon.