Congestion and redness on the outside of the cat's ears may be caused by hot weather, stress reaction, ear mites, fungal infection, or other reasons. You need to take the cat to a cool place and then check whether there are ears in the cat's ear canal. Mites or skin diseases, if it is a skin disease, it must be treated in time.
Tip:
If your cat scratches its ears frequently, it is best to wear Elizabethan rings to prevent the cat from scratching its ears and causing infection.