Granular bumps on the cat's ears may be caused by folliculitis, parasitic infection, mosquito bites, or tumors. You need to check the cat for parasites, ear itching, hair loss, redness, etc. If If you have these symptoms, it is a skin disease. If you don’t have these symptoms, you need to observe whether the particles have become larger. It is best to take the cat to the pet hospital for examination to avoid delaying the condition.