Skin allergy, which is caused by allergens in the air, such as pollen, is the most common type of allergy triggering ear infections in dogs. Other types include food allergy and contact allergy, which is caused by direct contact with an allergen that can irritate the skin.3
References: 1. Pet ear infections. Nationwide Insurance website. Available at: https://phz8.petinsurance.com/pet-health/health-conditions/pet-ear-infections. Accessed July 21, 2020. 2. Overview of otitis externa. Merck Veterinary Manual website. Available at: https://www.merckvetmanual.com/ear-disorders/otitis-externa/overview-of-otitis-externa. Accessed August 7, 2020. 3. Paterson S. Discovering the causes of otitis externa. In Practice website. Available at: https://inpractice.bmj.com/content/38/Suppl_2/7. Accessed August 7, 2020. 4. Nuttall T. Successful management of otitis externa. In Pract. 2016;38(Suppl 1):17–21.