Pododermatitis is the medical name for a condition known as Bumblefoot in guinea pigs and rats. It occurs when bacteria enter a small break in the skin of the back foot and less often the front paw. The skin is visibly pink to red in colour and clearly inflamed. The foot can also become very swollen causing distortion of the foot and lameness.
The most common cause of this infection is abrasive floor litter which causes lesions that then become infected. The main bacteria involved is thought to be staphylococcus aureus but other bacteria and fungal infection may also be involved. Overweight animals are more susceptible.
Wire bottomed cages are not recommended because they are a known cause of pododermatitis. Use soft bedding which allows urine to drain away such as dust extracted chopped straw on top of newspaper or cellulose fibre bedding.
In the US, rat keepers have successfully treated bumblefoot (pododermatitis) in rats using chlorhexadine or betadine washes and a product called Blu-Kote, which contains sodium propionate, gentian violet and acriflavine in a base of water, urea, glycerine and isopropyl alcohol 32% by volume. In the UK the nearest equivalent we have is Purple Spray but according to US rat sources this is not as effective.
The Guinea Lynx forum mentions the use of Bacitracin-Neomycin-Polymyxin B (Neosporin) applied twice daily (after chlorhexidine soaks when the feet are ulcerated) and Baytril (10mgs/kg/day for a month) to deal with the problem systemically.
Rabbit keepers have found using Germolene New-Skin liquid bandage helps in the management of sore hocks. Other sources recommend Neosporin, Nitrofurazone ointment and even Preparation H (an over the counter treatment for haemmorhoids!)
Peter Gurney's notes on Bumblefoot in guinea pigs including the observation that in guinea pigs with bumblefoot who were treated with Griseofulvin for fungal problems, the problem often showed some improvement.