Hard bumps on cats may be early symptoms of cat ringworm. After the owner finds out, they should isolate the cat to prevent it from spreading to other pets. Then take the cat to the pet hospital for examination and treatment. During the period, the cat should wear an Elizabethan ring to prevent Scratch the itchy cat at the affected area, improve the cat's diet, and feed the cat some nutritious food to enhance the cat's body resistance and promote the cat's recovery.