AffectedAnimals:
Female dogs are more likely to develop Addison's disease.  Younger dogs of an average age of four to five years are more commonly affected than older dogs. Any breed of dog can develop Addison's disease, although in some studies, the majority of affected dogs were of mixed breeding. Veterinarians have observed that Labrador retrievers, Rottweilers, and West Highland white terriers seem to be diagnosed with Addison's disease at a higher frequency than other breeds.

Overview:

Clinically known as canine hypoadrenocorticism, Addison's disease results from the decreased production of steroid hormones by the adrenal glands. The common symptoms of Addison's disease are not very specific, and can include lethargy, weakness, gastrointestinal upset, and poor appetite. Often these symptoms appear intermittently during an extended period of time.

Although some dogs may be diagnosed while in a relatively stable condition, most are diagnosed when an Addisonian crisis develops -- a severe stage of the disease in which shock and collapse can occur. If a dog is treated successfully for an Addisonian crisis, however, the long-term outlook is excellent, as most dogs can be controlled with oral or injectable medications to replace the deficient hormones.