Ear Infection or Otitis externa is the inflammation of the external ear that extends up to the ear canal. This is more commonly known as the "swimmer's ear" and occurs both on human and animals. It is more prevalent on dogs with long floppy ears such as Cocker Spaniels. 

Otitis externa can be caused by fungi, bacteria or parasites present inside the dogs' ears. The moisture and dirt inside the ears makes it a suitable environment for microbial growth. Presence of these microorganisms is characterized by frequent scratching of the ears and swelling and redness of the infected part. The infected dog tends to be more irritable, show signs of depression and would often tilt its head towards the infected side. 

Dogs with anatomically long floppy ears are more prone to infection and needs to have more frequent visits to the veterinarian. Early detection of ear infection would lessen the probability of the condition leading to deafness, severe pain and inflammation. 

The veterinarian will remove foreign objects and dirt that cause the infection. An anti-bacterial or anti-fungal treatment will be applied to the infected part. In some cases, the veterinarian would need to flush an ear wash solution into the dog's infected ear to kill the microorganisms causing the infection. The veterinarian may prescribe topical applications of anti-fungal creams every after bath. Antibiotics may also be prescribed to be taken for at least 2 weeks. 

Dog owners should not attempt to medicate their dogs on their own as this could cause trauma to the animal and could worsen the condition. They should only follow what the veterinarian prescribes and should not try to overdo it. 

Dogs that were once infected with Otitis externa are more likely to be infected again. There are cases when the microorganisms would not anymore respond to the earlier medication prescribed because they become immune to it. 

It is important to keep the ears of your dogs dry and clean to prevent growth of microorganisms that could cause infection. An ear cleaner, which is slightly acidic, may be applied into the dog's ear canal. Soften the dirt and wax by massaging the base of the ear for 20-30 seconds before wiping out the excess fluid. This should be done at least twice a week or as prescribed by the veterinarian. 

Proper grooming and diet contribute a lot to the prevention of any illnesses and infections. Trim the hair around the dog's ears to allow more air flow and keep the ear canal dry and unsuitable for microbial growth. Dogs should not be fed with allergy-causing food as this may increase the tendency to acquire ear infection.