Yellow hair on Bichon Frize ears may be caused by malnutrition, sticky dirt, or old age. The owner needs to determine which situation it is and then prescribe the right medicine. Sticky dirt can be washed away by bathing. If you are malnourished, it is best to improve your diet and increase the amount of food in cans. If it is caused by old age, you can feed more hair care products such as seaweed powder.