 Cutaneous warts are most common in younger animals (under 2 years) and usually spontaneously regress due to the animal's immune response without significant scarring.The duration of infection is very variable (from one month to over a year) and recurrence is possible.Warts caused by the "Xipapillomavirus" group have a cauliflower-like appearance and can attain the size of a fist; most common on the head, neck and shoulders, they may also occur in other locations.