The first sign that your cat may be suffering from a skin problem may be what is referred to as a hot spot. A “hot spot” may be a crusty, red and possibly even ooozing patch of skin. In some cases, hair loss may occur as well.
The most common conditions which can cause cat hot spots are abscesses, bacterial infection, eosinophilic granuloma, eosinophilic plaques, flea allergy dermatitis (also known as flea bite hypersensitivity), miliary dermatitis in cats, pyoderma-deep, ringworm, and squamous cell carcinoma.