Loss of appetite is called anorexia. A variety of disease can cause anorexia. It may be associated with significant weight loss. Anorexia should be differentiated from early satiety or painful swallowing.
Following are the important cause of anorexia
Depression : Patients will have depressed mood ,disturbed sleep and inertia
Drugs : Certain drugs are well known to produce anorexia following are the common agents Digoxin, narcotics, diuretics, amphetamines, antidepressants (SSRIs), and antihypertensives (especially ACE inhibitors)
Anorexia nervosa : Patients usually avoid food than anorexia due to alteration in body perception. Seen in females they are usually very thin, hypothermic and will have constipation.
Congestive heart failure : Occur only in advanced heart failure. Patient will have leg edema and breathlessness.
Hepatitis : In patients with hepatitis anorexia occur prior to clinical jaundice. Patient will have associated right sided abdominal pain.
Cancer : Prominent in gastric and pancreatic cancer and in cancer with liver metastases. In these patients weight loss is out of proportion to anorexia.
HIV infection : Anorexia occur as a part of disease or due to opportunistic infection or due to side effects of drugs.
Uremia : Waxy oedema sallow colour and decreased urine output are seen.
Addison disease : It is due to deficiency of hormone cortisol. Patients will also have fatigue or tiredness low blood pressure increased skin pigmentation especially of palmar creases and buccal mucosa.
Mesenteric ischemia : patients will develop abdominal pain after food intake due to poor blood supply to intestine, so they avoid eating. Features of systemic vascular disease is found.
Hypothalamic lesion : Certain lesions of hypothalamus such as tumors can cause visual field defect and anorexia .