Cushing's disease, also called hyperadrenocorticism, is a condition that occurs mostly in dogs aged six years or more. This disease is characterised by cortisol overproduction in the adrenal glands. The disease can progress slowly, and dogs may not appear to be seriously ill for a long time. Many owners believe that their dogs are simply getting old. However, by the later stages of this disease, many dogs have obvious and serious symptoms.
Cushing's disease often causes dogs to develop a sagging belly. This is because the disease encourages the body to redistribute fat reserves in the abdomen. Loss of muscle strength, often mistaken for weakness due to ageing, also reduces the ability of the abdomen to support itself. A dog suffering from Cushing's disease may appear potbellied, even if he is not otherwise fat.
Thinning of the skin is a common symptom of Cushing's disease in dogs. As the disease progresses, the skin may show blood vessels more prominently, bruise easily and begin to shed its hair. According to the Washington State University College of Veterinary Medicine, this condition causes hair loss primarily on the body, rather than on the feet or head.
Cushing's disease may also cause dogs to drink and eat more, with the resultant increase in waste. According to Doctors Foster and Smith, over 85 per cent of animals with Cushing's disease drink between two and ten times more than normal, and about 80 per cent show a significant increase in appetite. Dogs with this problem may appear to break their house training, since their bladders and intestines fill more quickly than they're used to. They may also ask to go out at unusual hours, such as the middle of the night. The severity of this problem increases over time.
More rarely, dogs with Cushing's disease develop blood clots in their lungs. Your dog may pant excessively, suffer from weakness or show sudden and rapidly worsening respiratory problems. This symptom is very serious, and you should visit the vet immediately if your dog shows signs of breathing problems.