Cowpox is a member of the orthopoxvirus family and I have not encountered it in my The Woodlands and Conroe dermatology offices as it is only found in Great Britain, Russia and some parts of Europe. However, with international travel it is very possible that Cowpox may appear in Texas. Cowpox typically is an infection of cows but is transmitted to humans from rodents and cats. Approximately one week after exposure to Cowpox, a sudden onset of flu like symptoms occurs followed by flat lesions that occur on the hands and fingers and sometimes the face. The lesions become vesicular (blister like) which develop into a pustule. The pustule become hemorrhagic with a purple/black appearance and ultimately a black eschar by week 3. The systemic flu like symptoms persist until this eschar appears. This black eschar resembles an Anthrax eschar, but the differentiating factor is that the Anthrax eschar occurs 6 days after exposure rather than 3 weeks. Orf (see blog entry Viruses – Farmyard Pox) also has a similar appearance to Cowpox except much less edema surrounds the lesion in Orf. Healing usually occurs after 2 months but scarring is very common.
