Hotspots (not the wireless kind!) are localized areas of pyodermatitis that can occur in any furred animal, but happen most frequently in dogs. Pyodermatitis is a bacterial infection and inflammation of the skin. Pyo refers to the pus produced by bacteria in an infection, and dermatitis is inflammation of the skin. Hotspots on dogs usually look like a roundish area of red, hairless, infected skin.