For reasons that elude me, I keep getting a stupid message that my post is flagged as spam. HELLO? I'll take out link and see if this works.
Alex, assuming that you had them scraped for mites, then this article runs through other very likely causes:
seborrheic ear edges in a patient with hypothyroidism.
Endocrine diseases that can produce ear edge changes include hypothyroidism and light-responsive alopecia. The key to differentiating between the two is assessing whether any other clinical signs are present. With hypothyroidism , weight gain, exercise intolerance, hyperpigmentation, seborrhea and symmetrical hair loss may be present. A free thyroxine blood concentration test (free T4) by equilibrium dialysis will help confirm the diagnosis. Light-responsive alopecia (Photo 3) can also present with symmetrical ear edge alopecia, seborrhea and hyperpigmentation. The results of blood work are usually normal, and, in contrast to hypothyroidism, no other systemic clinical signs are usually present. This disease is seen primarily in the Midwest and in northern climates during dark winters, resulting in a lack of natural sunlight exposure. Specific breeds affected include Doberman Pinschers, Labrador Retrieverss, Boxers and English Bulldogs.
Photo 3: Alopecia and hyperpigmentation of the ear pinna in a dog with light-responsive alopecia.
Atopy in some breeds such as Boxers and Labrador retrievers can manifest with crusty, alopecic ear edges. This is often mistaken for scabies since these dogs are pruritic and can have a positive pinnal/pedal reflex. It is certainly appropriate to treat for scabies, as anytime scabies is suspected, treatment should be initiated. However, if the condition persists after the appropriate scabies treatment is completed, atopy should be considered.
Photo 4: Malassezia dermatitis of the ear edge and nasal planum in two sibling Dachshunds.
Ear edge seborrhea due to Malassezia yeast or keratinization disorders can present in breeds such as Yorkshire Terriers and cocker spaniels, respectively. Skin smears can confirm Malassezia yeast, and a skin biopsy confirms keratinization defects such as vitamin A-responsive dermatosis. Yorkshire Terriers and Dachshunds are most commonly susceptible to Malassezia ear edge dermatitis (Photo 4). Scaling of the dorsal nasal planum may also be present. Vitamin A-responsive dermatosis usually results in a thicker ear edge scaling sometimes accompanied by crusting, follicular casts and fissuring.<<