A dentist comes to the OPD with pain, redness, swelling of the finger. He also complains of fever. On examination, there are small, grouped vesicles with clear fluid in them. Tzanck smear is done which shows tzanck cells. What is the causative agent?

The given clinical scenario describes herpetic whitlow. It is caused by HSV 1. It is often contracted by health care workers that come in contact with the virus; it is most commonly contracted by dental workers and medical workers exposed to oral secretions. On Tzanck smear, which is a rapid, diagnostic method, Tzanck cells are seen. These are multinucleated giant cells with faceted nuclei and homogenously stained ground-glass chromatin. Diagnosis of herpes simplex virus: Most sensitive test: HSV DNA detection by PCR. Most definitive test: Virus isolation. Cytopathology: Tzanck smear is prepared by Wright or Geimsa stain. PCR: can differentiate between HSV-1 and HSV-2 Reference: Ananthanarayan and Paniker&;s Textbook of Microbiology Tenth edition