Ear problems are common in cats – they may affect the pinnae (the ears sitting on top of the head), the external ear canal, the middle ear, and/or the inner ear – see structure and function of the ear in cats. The most common diseases affect the external ear (ear canal and/or pinnae).
Diseases affecting the pinnae
Wounds and trauma: Wounds affecting the pinnae are mostly a result of cat fights, with damage being sustained from bites or claws. A bite or scratch wound may result in a full thickness tear of the pinna, and in most cases this will need to be allowed to heal without attempting to suture the wound. In some cases, especially with bite wounds, there may be infection present, and a swelling with an abscess may develop. You should get your vet to check all injuries and swellings to the ear to determine what treatment may be necessary
Haematoma: A haematoma is a large blood-filled swelling caused by the rupture of a small blood vessel under the skin. It results in haemorrhage and blood accumulation between skin and cartilage. This is seen much more commonly in dogs than cats, and is usually caused by some form of trauma to the ear – in some cases caused by the cat itself shaking or scratching the ear violently. Marked swelling usually develops rapidly, and the condition can be quite painful. Your vet will need to determine both the underlying cause of the irritation to the ear and also determine the best treatment for the haematoma (which may include surgery in some cases). Often there is some fibrosis and scarring after a haematoma forms that can cause slight deformity of the ear (a ‘cauliflower ear’ appearance).
Solar dermatitis: This is inflammation, usually of the ear tips, caused by exposure to ultraviolet (UV) sunlight, and occurs more commonly in cats with white or pale-coloured ears and in countries with high levels of UV sunlight radiation. In the early stages, the skin appears pink and scaly, but as the condition progresses it may become crusted, ulcerated and may bleed. If left untreated, this condition may progress to squamous cell carcinoma (a malignant skin tumour). Surgical removal of the ear tips is the treatment of choice, and the end appearance is usually very acceptable, and has no detrimental effect on the cat. To reduce the risk of this condition in countries where there is significant exposure to UV radiation and in cats at risk, it will help to:
- avoid exposure to sunlight during the height of the day (e.g., 10.00-15.00)
- Use a cat-safe sun-block on the ears and nose (ask your vet what you should use – some human products can be potentially toxic to cats, so it is best to use one specifically designed for cats)
Sarcoptic or Notoedric mange: This is caused by infection with a mites (Sarcoptes or Notoedres) in the skin and, although unusual, can cause intense irritation and pruritus (itchy skin). The ears are often a major site of irritation. The diagnosis can be made by your vet identifying the mites in scrapings taken from the skin. If present, the mites can be treated effectively with medications from your vet.
Autumn Harvest Mite (Trombicula autumnalis): This can be a seasonal problem in outdoor cats with typical orange ‘pinhead’ larvae of the mite being present on the ears, face and feet, which cause irritation. Effective treatments are available from your vet.
Diseases affecting the ear canal
The term ‘otitis externa’ is sometimes used, and this really refers to any inflammatory condition affecting the ear canal (or even the pinnae). This is not a disease itself, as most diseases affecting the ear canal will cause some degree of inflammation.
Parasitic otitis, Otodectes cynotis: This is a very common cause of otitis externs in cats, especially young cats. It is caused by infection with an ear mite (Otodectes cynotis) which can readily be spread from one cat to another. The mite itself is just visible to the naked eye as a dirty white speck, often actively moving. Very large numbers of these mites can be found in ears, even of young kittens. The mites generally spend their whole life in or around the ear canal, but may be able to survive for short periods (up to 2-3 weeks) in the environment. Some cats show few signs of ear mite infection, but in most the mites produce a strong allergic response with intense itching. The skin linking the ear canals can become thickened, the cat will scratch at the ears and shake its head, and there will typically be a discharge from the ear with dark or black waxy material. In some cases there may be secondary bacterial infection as well. Diagnosis and treatment is usually straightforward, but may not necessarily involve using ear drops. Some ‘spot-on’ insecticides such as selamectin are very effective against ear mites and direct application to the ears may not be required. In some cases, careful cleaning of the ear may be needed, but this should be done by your vet, and may require an anaesthetic to be carried out safely.
Bacterial infection: Bacterial (suppurative) otitis often occurs secondary to some other ear problem – ear mites, a foreign body, trauma etc, although sometimes an infection will occur with no obvious predisposing cause (especially in kittens). Fungal infections (with yeasts) may also be present. Pus is usually evident in the ear canal, there may be a bad odour, and the cat will be uncomfortable. Your vet will need to carefully examine your cat or kitten to search for underlying causes, and may need to administer a short anaesthetic to fully examine and/or clean the ear. Antibiotics will be required and your vet may give you antibacterial ear drops to administer. Again, don’t be tempted to buy ear drops from a pet shop or elsewhere – these will not be as effective as the treatment your vet can give, and may even be dangerous, especially if there is any damage to the tympanic membrane.
Foreign bodies: Although much more common in dogs than cats, occasionally a foreign body (such as a grass seed or blade of grass) will get stuck in the ear canal. This usually causes sudden onset of pain, scratching at the ear, holding the head to one side, etc. Your cat will often need a short anaesthetic to safely remove the foreign body without causing any damage.
Tumours of the ear canal: In older cats especially, tumours may develop in the skin lining the ear canal. These growths may be benign polyps or tumours, but in many cases are malignant (most commonly ceruminous gland adenocarcinoma). These often appear as multiple small nodules, frequently with secondary infection (which may be the most obvious sign). Your vet will need to examine the cat, and may take small biopsies under an anaesthetic to determine the cause and the most appropriate treatment. In some cases surgery may be needed.
Aural resection is a surgical procedure that is occasionally needed in cats to treat external ear disease which results in chronic thickening of the lining of the canal, or to get access to tumours arising in the horizontal canal. The operation removes the outside wall of the vertical canal so opens the ear and allows access to the horizontal canal.
Diseases affecting the middle and inner ear
Because of their very close association, diseases that affect the middle ear (otitis media) often also affect the inner ear (otitis interna), causing disturbance to balance. Affected cats may hold their head to one side, may have some difficulty in walking, and may have a tendency to walk in circles towards the affected side. In some cats disease of the middle ear will also spread to the external ear or vice versa, where the integrity of the ear drum (tympanic membrane) is compromised. Some of the more common conditions include:
Infection of the middle ear – this is seen more commonly in kittens than adult cats and usually results from infection spreading up the eustachian tube (the small tube that connects the nose to the middle ear). This may occur as a complication from upper respiratory infections. In cases of suppurative otitis externa, if the tympanic membrane is compromised then the infection may readily spread to affect the middle and inner ears also.
Polyps – benign polyps may develop within the middle ear or the eustachian tube of cats. Cats of any age may be affected, but it is most commonly seen in young adults. These are benign inflammatory masses, but the underlying cause remains unknown. The polyp may grow in the nasopharynx (throat) and/or the middle ear of the cat, and if in the middle ear it may eventually cause the ear drum (tympanic membrane) to rupture and be present in the external ear canal.
Tumours – rarely the middle ear may be affected by the presence of benign or malignant tumours
The investigation and management of middle ear disease will vary from one cat to another. Usually X-rays (or more advanced imaging such as CT or MR scans) will be valuable to assess the middle ears, and in most cases thorough examination of the ear canal will be needed under anaesthesia. Flushing of the middle ear and/or obtaining samples from the middle ear (for cytology or culture) may be needed to determine the most appropriate treatment. In some cases, surgery may be required, which may include a procedure called ‘bulla osteotomy’ where part of the bony wall of the middle ear is removed so that a mass (e.g., a polyp) can be successfully removed completely.