If the foot pad on one or more of your cat’s feet becomes puffy and swollen, there’s a good chance she has pillow foot, medically termed feline plasma cell pododermatitis. It means the skin on the foot has become inflamed due to infiltration of the pad with plasma cells, which belong to the immune system. The thought is that the immune system somehow becomes overstimulated, resulting in the inflammation.
In some cats, the condition rights itself on its own. Others need an immune suppressant such as prednisolone. If it looks like your cat has pillow foot, and certainly if it’s making her limp or seems to be causing her pain, take her in to be examined and potentially treated.