Dermatitis specific to the feet is known as pododermatitis and is a common problem in pet guinea pigs. Guinea pigs have little footpads on the soles of all four feet. With constant abrasion on harsh bedding, particularly in wire-bottomed cages, the skin becomes thickened and hardened. This damaged skin cracks and ulcerates and then is invaded by bacteria to form nasty, non-healing sores. Eventually the lesions can become so deep that tendons and bones are exposed. Obese guinea pigs are particularly susceptible.
This condition is painful and notoriously difficult to treat. Affected feet may be treated with antibacterial foot soaks, antibiotics, bandaging and pain relief. Fat animals need to be gradually dieted by avoiding all concentrates and pellets and just feeding hay and dark leafy greens. Avoid wire bottomed cages and use a soft substrate such as hay or grass.