Disorders of the Outer Ear in Cats

When a cat develops an ear hematoma, the ear flap (pinna) fills with blood and swells—sometimes just a little, sometimes so much that it closes off the ear canal. This condition is more common in dogs but can occur in cats as well.

Ear hematomas occur when scratching or head shaking breaks a blood vessel. Cats often scratch at their ears or shake their heads because of an ear infection, which can lead to a hematoma. The swollen ear feels soft and fluid-filled. The cat can feel uncomfortable.

Treatment typically involves surgery to drain and flush the swelling. A soft tube drain may be placed to prevent fluid from reaccumulating. Medications can also be prescribed. If left untreated, the hematoma will eventually go away on its own as the fluid is absorbed by the body. However, the healing process can take several months. The pinna often scars and shrinks, leading to a crinkled “cauliflower ear” appearance.

Cats can develop dermatitis (skin inflammation) after bites from blood-feeding insects like mosquitoes, fleas, and flies. Small bumps often form on ear tips, may scab, and can become sores.

• Mosquito allergy can cause crusted, slow-healing sores on the outer ears, nose, and rarely eyelids or footpads. These tiny bumps crust, ooze, and then dry, leaving small hairless patches. Severe cases can progress to raised white-pink nodules and widespread crusted sores. Itching varies, and nearby lymph nodes can enlarge. Treatment includes keeping the cat indoors and using only vet-prescribed, cat-safe insect repellents in areas with mosquitoes.

• Rabbit fleas (mainly in Europe and Australia) can attach firmly and often affect ear tips, causing inflammation.

• Biting flies (such as stable flies and black flies) can trigger dermatitis. Treatment includes cleaning up animal waste to deter flies and using vet-prescribed anti-inflammatory medication.

Mange is caused by microscopic mites. Several mite species affect cats.

• Otodectic mange is a common cause of external ear infection. Mites affect the ears and skin, causing redness, hair loss, itching, and general inflammation.

• Sarcoptic mange is rare in cats. Itching is severe. It spreads through contact with infected animals or contaminated items.

• Notoedric mange is more common in cats than sarcoptic mange. It causes intense, constant itching around the ears, head, and neck, with head shaking, redness, hair loss, and grayish-yellow skin crusts.

Diagnosis is based on symptoms, exposure history, exam findings, and identifying mites on scrapings of skin examined under the microscope. Because mites can be hard to detect, vets sometimes treat for them even without confirmation.

Treatments include dipping the affected animal in medicated baths and applying mite-killing medications to the skin, injecting them, or giving them by mouth. Corticosteroids can help severe itching. Clean all bedding, brushes, and household items thoroughly, and treat all other cats and dogs in the home, as mites can survive for some time off the host.

Proliferative and necrotizing otitis externa is rare and can affect cats from 2 months to 12 years old, most often around age 4. Any breed can be affected. It may be slightly more common in males. It doesn't occur in dogs.

The exact cause is unknown, though allergies and other responses by the immune system have been proposed.

The condition usually involves the inner surface of the ear flap (pinna) and the area near the ear canal, but it can also spread deeper into the canal. Skin around the ears, eyes, and mouth can also be affected. Thick skin crusts may form and bleed or ulcerate, and secondary bacterial or yeast infections can worsen signs. Most cats don't focus on the lesions, but mild itching and discomfort can occur when ulcers form.

Vets may suspect this disease based on specific symptoms. Diagnosis is confirmed with a skin biopsy.

Some cases resolve on their own over 12–24 months. However, treatment is recommended.

Medication applied to the skin can help clear signs. If the cat has an ear infection at the same time, that may also need to be treated.

Solar dermatitis (also called solar dermatosis or actinic keratosis) is an inflammatory skin disease that can affect cats. It is caused by prolonged exposure to the sun's radiation.

Solar dermatitis is most common in white cats or cats with white ears exposed to sun over time. Light-colored, thinly haired areas of skin, like the ears, nose, and eyelids, are commonly affected. Your vet might prescribe a steroid cream for relief of mild dermatitis caused by sun exposure.

Early signs include redness and scaly skin on ear tips with little hair. Later, crusting, discharge, and slow-healing sores can appear. Precancerous or cancerous lesions (such as squamous cell carcinoma) can develop. Earlier skin damage can become skin cancer years after exposure.

In addition to physical exam findings, veterinarians might perform skin biopsies or other tests to confirm a diagnosis or rule out look-alike conditions.

Prevention is best. Limit sun exposure by keeping cats indoors (especially during the sunniest hours of the day). Cats' grooming habits usually limit the usefulness of sunscreen, but if sun exposure can't be avoided, sunscreen can be tried. Make sure to follow your vet’s recommendations and use only a sunscreen that's safe for cats.

Squamous cell carcinoma of the ear tips is treated with surgical removal, followed by radiation therapy or medications applied to the skin.