Anorexia (Loss of Appetite) in Cats
Dr. Etienne Cote
The reasons for which animals refuse to eat may be grouped into two major categories: Psychological causes imply that something in the animal's environment has caused him to lose his appetite. Examples include moving to a new home, having a new person or new animal in the home, and switching to a new pet food.
Psychological and Medical
Medical causes are disease processes that result in the loss of appetite.
A major difference between psychological loss of appetite and disease-related loss of appetite is that when there is disease, additional symptoms are usually present. These symptoms can include the new development of excessive salivation (drooling), vomiting, diarrhea, lethargy or sluggishness, weight loss, labored breathing, signs of infection such as discharge of pus or blood, or sudden changes in behavior.
Common diseases that make animals unwilling to eat include the following:
If the esophagus (tube in the throat that connects the mouth to the stomach), the stomach, or the intestine, is inflamed (irritated) by disease, eating can become uncomfortable or nauseating, resulting in anorexia. Diseases that can cause this kind of irritation include parasites (worms), viruses such as parvovirus and coronavirus, other infections such as bacterial and fungal infections, ulcers, food allergy, inflammation of unknown cause ("idiopathic"), and certain infiltrative cancers. A complete or partial blockage of the digestive tract can also cause unwillingness to eat. This most often occurs with foreign bodies (objects that are swallowed and become stuck partway down the digestive tract) and cancers of either a benign or malignant nature.
Gastrointestinal diseases in general often will also cause increased salivation, vomiting, diarrhea, and sometimes (particularly when more severe) lethargy and sluggishness.