Generalized cowpox infection in a patient with Darier disease

Funding sources: none. Conflicts of interest: none declared. Madam, Cowpox virus belongs to the family of Poxviridae, genus Orthopoxvirus, and is closely related to smallpox, vaccinia and monkeypox virus.1 Human cowpox is a zoonotic infection transmitted by mouse‐hunting cats or pet rats having their reservoir in wild rodents.2 The confusing names of cowpox and the closely related vaccinia virus originate from 1776 when Edward Jenner inoculated material from a dairymaid’s hand to a boy who was subsequently protected against smallpox. Jenner described the difficulties of finding appropriate cowpox lesions in cows, suitable for vaccination.3 In fact, cows were later shown to be only accidental hosts of cowpox virus.4 In immunocompetent individuals, cowpox show a self‐healing disease with usually one painful lesion that passes the stages of a macule, papule or nodule, vesicle, pustule, ulcer and eschar with surrounding erythema and oedema.1 In contrast, in immunodeficient or eczematous patients, cowpox infection may become generalized, be accompanied with systemic symptoms or even be fatal.5, 6