This section is from the book "The Dogs Of Great Britain, America, And Other Countries. Their Breeding, Training, and Management in Health and Disease", by John Henry Walsh (Stonehenge). Also available from Amazon: The Dogs Of Great Britain, America And Other Countries.
Many dogs, especially of sporting breeds, contract an inflammation of the membrane or skin lining of the ear, from high feeding generally, and exposure to the weather. This causes irritation, and the dog shakes his head continually. This, together with the tendency to spread externally, causes an ulceration of the tips of the ears of those dogs, such as the hound, pointer, setter, spaniel, etc., which have these organs long and pendulous. Hence, the superficial observer is apt to confine his observations to this external ulceration, and I have even known the tips of the ears cut off in the hope of getting rid of the mischief. This heroic treatment, however, only aggravated the malady, because, while the incessant shaking caused the wound to extent, the internal inflammation was not in the slightest degree relieved. The pointer is specially liable to "canker," as shown at the tips of the ears, inasmuch as there is little hair to break the acuteness of the "smack" which is given in the shake of the head. Long-haired dogs, on the other hand, are quite as liable to the real disease, as shown by an exami-nation of the internal surface, owing however to the protection afforded by the hair, the pendulous ear is less ulcerated or inflamed.
Whenever, therefore, a dog is seen to continually shake his head, and ineffectually endeavor to rub or scratch his ear, not being able to succeed, because he cannot reach the interior, an examination should at once be made of the passage leading into the head. If the lining be red and inflamed, there is clear evidence of the disease, even though the external ear be altogether free from it. On the other hand, the mere existence of an ulceration on the tips of the ears is no absolute proof of "canker," inasmuch as it may have been caused by the briars and thorns which a spaniel or hound encounters in hunting for his game. Still it should lead to a careful inspection, and, if it continues for any length of time, it may be generally concluded that there is an internal cause for it. The treatment should in every case be chiefly directed to the internal passage; the cap which is sometimes ordered to be applied to the head, with a view of keeping the ears quiet, has a tendency to increase the internal inflammation, and should not therefore be em-ployed. The first thing to be done, is to lower the system by pur-gatives (11), (12), (15). or (16), with low diet, including no animal food.
As soon as this has produced a decided effect, the nitrate of silver wash (22), the ointment (58a), melted, or the sulphate of zinc (20), should be dropped into the ear-passage, changing one for the other every second or third day. At the same time the sores on the edges of the ears may be daily touched with bluestone, which will dry them up. In slight cases, this treatment will suffice for a cure, if carried on for three weeks or a month. In long-standing attacks, however, a seton must be put into the back of the neck; this seldom fails to afford relief. If the inflammation in the external ear has been so great as to produce abscesses, they must be slit open with the knife to the very lowest point, as wherever matter is confined in a pouch there can be no tendency to heal. The dog should be muzzled and the head held firmly on a table, whenever any remedial fluid is applied internally to the ear. Deafness may result from canker, or from rheumatic or other inflammation of the internal ear. As no treatment is likely to be beneficial, there is no necessity for enlarging on the subject; the only remedy at all to be relied on, in recent cases, is the seton in the back of the neck.