Ear Margin Hyperkeratosis in Dogs

Symptoms of this condition may include:

• Thickening of the skin on the ears
• Mild lesions on the pinna
• Scaly or greasy plugs on the pinnal margin, nonpruritic 
• More severe cases affect the entire ear pinna, not just the edges
• Head shaking

Types

Ear margin hyperkeratosis can also be known as ear margin seborrhea or orthokeratotic hyperkeratosis.  It is characterized by abnormal thickening of the outer layer of skin.  This condition is commonly found to affect dogs with pendulous ears such as Dachshunds and Cocker Spaniels.  As the condition progresses, the scaling often moves from the edge of the ear to the entire ear.

When you arrive at the veterinarian’s office, she will start her diagnostic process by collecting a verbal history from you.  For example, she will want to know what symptoms you have seen on your dog and when you first noticed the development of his symptoms.  She will also want to know how fast each symptom has been progressing and if it seems to impair his daily routine.  She will then proceed with performing a full physical exam.  While it may be obvious the lesions are on his ears, she will want to check him over entirely for other symptoms that could be indicative of an underlying cause of his condition.  

In cases of suspected ear margin hyperkeratosis, your veterinarian may need to rule out other possible medical conditions first.  For example, fly bite dermatitis in dogs causes very similar symptoms as to those of ear margin hyperkeratosis.  Additional diagnoses she may need to rule out include scabies and solar dermatitis, to just name a few.  In order to rule out these conditions, she may want to perform diagnostic testing.  It would involve taking a skin scraping sample from the affected area of your dog.  She will scrape a small sample from the superficial layer of your dog’s ear tips to examine under the microscope.  This will allow her to evaluate the appearance of the skin cells as well as rule out external skin parasites.

Ear margin hyperkeratosis can be complicated by a yeast infection or bacterial infection.  She will want to ensure your dog does not currently have an ear infection in his canal as well as on the surface of his ear pinna.  This may involve taking a skin cytology sample from his ears.  Often, the veterinarian only needs to take a piece of scotch tape, apply it to your dog’s ear lesions and then stain it with a special stain.  She will then examine it under the microscope for the presence of bacteria or yeast.

Other testing may be requested by the veterinarian depending on your dog’s symptoms.  If she suspects his condition is a secondary development to a different illness, she may want to perform diagnostic testing to determine the cause. Depending on what she suspects, the testing can vary.

Many dogs with this condition respond well to medicated shampoos with keratolytic and keratoplastic properties. Examples would be tar, sulphur, salicylic acid, selenium sulphide, or benzoyl peroxide.  Your veterinarian will be able to prescribe you this as it is not something that can be found over the counter.  If you do find something over the counter, it may be similar, but the prescription shampoo is more concentrated and therefore typically works better.  

Close clipping of the hair on the affected area is also helpful.  This will prevent matting of the hair and accumulation of seborrhea within the fur.  It will not necessarily prevent the condition from developing but it may slow or stop its progression.

Other treatments will be administered depending on your dog’s needs.  She may send you home with an ointment or spray to apply to the ears.  If there is a yeast or bacterial overgrowth, it is possible oral medications will also be sent home for you to administer over a course of time. If your veterinarian discovers there is an underlying cause to your dog’s symptoms, she will administer therapies in accordance to that illness.