Nasal depigmentation, also called Dudley nose, is a syndrome of unknown cause that may be a form of vitiligo. A nose that is solid black at birth gradually fades to a chocolate brown, or in the case of complete depigmentation, to pinkish white. Some dogs experience a remission in which the nose spontaneously becomes darker. Depigmentation primarily affects the skin of the nose where hair is absent. It tends to occur in Afghan Hounds, Samoyeds, white German Shepherd Dogs, Doberman Pinschers, Irish...
Allergies are a frequent trigger for hair loss in dogs. Like people, dogs can have an allergic reaction to foods, environmental triggers such as pollen, or to parasites like fleas or mites.
Flea bites are behind most dog allergies, however. Along with hair loss from licking and biting the irritated areas, signs of flea allergies include itching and redness. For a particularly allergic dog, it may take as little as one flea bite to start an allergic reaction that lingers for days.
While any dog can have allergies, some are more prone to them than others. Treating your dog's allergies may include topical or internal medication, immunotherapy, a change in diet, and avoiding the allergen.
Hair loss in dogs may also be caused by hyperadrenocorticism, or Cushing's disease, a condition caused by the overproduction of the hormone cortisol. Less commonly, it is due to a tumor on one of the adrenal glands.
Medication is available to treat both forms of Cushing’s disease. However, while not commonly recommended, surgery can be done to remove the tumor associated with the adrenal form of Cushing’s disease.
Cushing's disease is more common in dogs 6 years or older. Other signs of Cushing's disease include eating, drinking, and urinating more, as well as having a pot-bellied appearance. Take your dog to the vet if you notice any of these signs.
Some dogs are more prone to baldness than others. Bald spots on the outer ear, chest, back, thighs, or lower neck may appear in greyhounds, whippets, Chihuahuas, dachshunds, and Italian greyhounds, usually after their first year.