In the early stage of otitis media in dogs, only the external auditory canal is flushed, edematous, and itchy, and light yellow serous secretions flow from the ear canal. The dog appears restless, often shaking its head and scratching its ears. As the disease progresses to the later stages, local swelling intensifies, or pustules appear, and brown-black foul-smelling purulent secretions flow out, which often leads to hair loss at the base of the ears or dermatitis. The sick dog's hearing is reduced, and repeated attacks may even cause tumors, leading to ear disease. Thickened skin and hearing impairment.