There are many cases of redness and fever in the left ear, as follows: 1. auricular diseases: congestion, fever or pain due to auricular skin infection, auricular chondromyelitis or local skin infection, with symptoms of congestion, pressure or fever, and in severe cases, possible signs of pus. 2. external auditory canal diseases: when there is acute external otitis of the ear, or boils in the external auditory canal, there will also be redness and fever in one ear. 3. 4. Stress or excitement: It is possible for the patient’s capillaries to dilate, and redness and fever in the ear may occur. 5. Environmental changes: If the patient enters the room in a cold climate, blood circulation is accelerated, which can also lead to redness and fever in the ear.