Anorexia (symptom)
Anorexia is the decreased sensation of appetite
The appetite is the desire to eat food, felt as hunger. Appetite exists in all higher life-forms, and serves to regulate adequate energy intake to maintain metabolic needs. It is regulated by a close interplay between the digestive tract, adipose tissue and the brain. Decreased desire to eat is...

. While the term in non-scientific publications is often used interchangeably with anorexia nervosa
Anorexia nervosa
Anorexia nervosa is an eating disorder characterized by refusal to maintain a healthy body weight and an obsessive fear of gaining weight. Although commonly called "anorexia", that term on its own denotes any symptomatic loss of appetite and is not strictly accurate...

, many possible causes exist for a decreased appetite, some of which may be harmless, while others indicate a serious clinical condition or pose a significant risk.

Clinically important causes

  • Acute radiation syndrome
  • Acute viral hepatitis
    Hepatitis is a medical condition defined by the inflammation of the liver and characterized by the presence of inflammatory cells in the tissue of the organ. The name is from the Greek hepar , the root being hepat- , meaning liver, and suffix -itis, meaning "inflammation"...

  • Addison's disease
    Addison's disease
    Addison’s disease is a rare, chronic endocrine disorder in which the adrenal glands do not produce sufficient steroid hormones...

  • Atypical pneumonia
    Atypical pneumonia
    Atypical pneumonia aka "walking pneumonia" is a pneumonia not caused by one of the more traditional pathogens, and with a clinical presentation inconsistent with typical pneumonia. It can be caused by a variety of microorganisms...

  • AIDS
    Acquired immune deficiency syndrome or acquired immunodeficiency syndrome is a disease of the human immune system caused by the human immunodeficiency virus...

  • Anorexia nervosa
    Anorexia nervosa
    Anorexia nervosa is an eating disorder characterized by refusal to maintain a healthy body weight and an obsessive fear of gaining weight. Although commonly called "anorexia", that term on its own denotes any symptomatic loss of appetite and is not strictly accurate...

  • Anxiety disorder
    Anxiety disorder
    Anxiety disorder is a blanket term covering several different forms of abnormal and pathological fear and anxiety. Conditions now considered anxiety disorders only came under the aegis of psychiatry at the end of the 19th century. Gelder, Mayou & Geddes explains that anxiety disorders are...

  • Appendicitis
    Appendicitis is a condition characterized by inflammation of the appendix. It is classified as a medical emergency and many cases require removal of the inflamed appendix, either by laparotomy or laparoscopy. Untreated, mortality is high, mainly because of the risk of rupture leading to...

  • Cancer
    Cancer , known medically as a malignant neoplasm, is a large group of different diseases, all involving unregulated cell growth. In cancer, cells divide and grow uncontrollably, forming malignant tumors, and invade nearby parts of the body. The cancer may also spread to more distant parts of the...

  • Chronic renal failure
    Chronic renal failure
    Chronic kidney disease , also known as chronic renal disease, is a progressive loss in renal function over a period of months or years. The symptoms of worsening kidney function are unspecific, and might include feeling generally unwell and experiencing a reduced appetite...

  • Congestive heart failure
    Congestive heart failure
    Heart failure often called congestive heart failure is generally defined as the inability of the heart to supply sufficient blood flow to meet the needs of the body. Heart failure can cause a number of symptoms including shortness of breath, leg swelling, and exercise intolerance. The condition...

    , perhaps due to congestion of the liver
    The liver is a vital organ present in vertebrates and some other animals. It has a wide range of functions, including detoxification, protein synthesis, and production of biochemicals necessary for digestion...

     with venous blood
    Venous blood
    Venous blood is deoxygenated blood in the circulatory system. It runs in the systemic veins from the organs to the heart. Deoxygenated blood is then pumped by the heart to lungs via the pulmonary arteries, one of the few arteries in the body that carries deoxygenated blood .Venous blood is...

  • Crohn's disease
    Crohn's disease
    Crohn's disease, also known as regional enteritis, is a type of inflammatory bowel disease that may affect any part of the gastrointestinal tract from mouth to anus, causing a wide variety of symptoms...

  • Dementia
    Dementia is a serious loss of cognitive ability in a previously unimpaired person, beyond what might be expected from normal aging...

  • End Stage Renal Failure
  • Depression
    Clinical depression
    Major depressive disorder is a mental disorder characterized by an all-encompassing low mood accompanied by low self-esteem, and by loss of interest or pleasure in normally enjoyable activities...

  • Hypervitaminosis D
    Hypervitaminosis D
    Hypervitaminosis D is a state of vitamin D toxicity.The recommended daily allowance is 400 IU per day. Overdose has been observed at 1925 µg/d...

  • Metabolic disorders, particularly urea cycle disorders
  • Sickness behavior
    Sickness behavior
    thumb|350px|right|[[Michael Peter Ancher|Ancher, Michael]], "The Sick Girl", 1882, [[Statens Museum for Kunst]]Sickness behavior is a coordinated set of adaptive behavioral changes that develop in ill individuals during the course of an infection....

  • Superior mesenteric artery syndrome
    Superior mesenteric artery syndrome
    Superior mesenteric artery syndrome is a very rare, life-threatening gastro-vascular disorder characterized by a compression of the third portion of the duodenum by the abdominal aorta and the overlying superior mesenteric artery...

  • Tuberculosis
    Tuberculosis, MTB, or TB is a common, and in many cases lethal, infectious disease caused by various strains of mycobacteria, usually Mycobacterium tuberculosis. Tuberculosis usually attacks the lungs but can also affect other parts of the body...

  • Thalassemia
    Thalassemia is an inherited autosomal recessive blood disease that originated in the Mediterranean region. In thalassemia the genetic defect, which could be either mutation or deletion, results in reduced rate of synthesis or no synthesis of one of the globin chains that make up hemoglobin...

  • Ulcerative colitis
    Ulcerative colitis
    Ulcerative colitis is a form of inflammatory bowel disease . Ulcerative colitis is a form of colitis, a disease of the colon , that includes characteristic ulcers, or open sores. The main symptom of active disease is usually constant diarrhea mixed with blood, of gradual onset...

  • Zinc deficiency
    Zinc deficiency
    Zinc deficiency is insufficient zinc to meet the needs of biological organisms. It can occur in both plants and animals. Zinc deficient soil is soil in which there is insufficient zinc to allow plants to grow normally.-Description:...


  • Amphetamine
    Amphetamine or amfetamine is a psychostimulant drug of the phenethylamine class which produces increased wakefulness and focus in association with decreased fatigue and appetite.Brand names of medications that contain, or metabolize into, amphetamine include Adderall, Dexedrine, Dextrostat,...

    Adderall is a brand name of amphetamine salts–based medication used for attention-deficit hyperactivity disorder and narcolepsy. It is a brand-name psychostimulant medication composed of racemic amphetamine aspartate monohydrate, racemic amphetamine sulfate, dextroamphetamine saccharide, and...

    ), dextroamphetamine (Dexedrine & Dextrostat)
    Dextroamphetamine is a psychostimulant drug which is known to produce increased wakefulness and focus as well as decreased fatigue and decreased appetite....

  • Antidepressants can have anorexia as a side effect
  • Byetta
    Exenatide is a medication approved in April 2005 for the treatment of diabetes mellitus type 2. It belongs to the group of incretin mimetics and is manufactured by Amylin Pharmaceuticals and Eli Lilly and Company....

    , a Type II Diabetes drug, will cause moderate nausea and loss of appetite
  • Dextromethylphenidate (Focalin)
    Dexmethylphenidate, otherwise known as d-threo-methylphenidate , is the dextrorotatory enantiomer of methylphenidate. It is a norepinephrine-dopamine reuptake inhibitor and releasing agent and thus a psychostimulant, which affects the CNS...

  • Abrupt cessation of appetite-increasing drugs, such as cannabis
    Cannabis is a genus of flowering plants that includes three putative species, Cannabis sativa, Cannabis indica, and Cannabis ruderalis. These three taxa are indigenous to Central Asia, and South Asia. Cannabis has long been used for fibre , for seed and seed oils, for medicinal purposes, and as a...

     and corticosteroid
    Corticosteroids are a class of steroid hormones that are produced in the adrenal cortex. Corticosteroids are involved in a wide range of physiologic systems such as stress response, immune response and regulation of inflammation, carbohydrate metabolism, protein catabolism, blood electrolyte...

  • Methamphetamine (Desoxyn)
    Methamphetamine is a psychostimulant of the phenethylamine and amphetamine class of psychoactive drugs...

      (treatment of ADD & ADHD and narcolepsy
    Narcolepsy is a chronic sleep disorder, or dyssomnia, characterized by excessive sleepiness and sleep attacks at inappropriate times, such as while at work. People with narcolepsy often experience disturbed nocturnal sleep and an abnormal daytime sleep pattern, which often is confused with insomnia...

  • Methylphenidate (Ritalin & Concerta)
    Methylphenidate is a psychostimulant drug approved for treatment of attention-deficit hyperactivity disorder, postural orthostatic tachycardia syndrome and narcolepsy. It may also be prescribed for off-label use in treatment-resistant cases of lethargy, depression, neural insult and obesity...

  • Chemicals that are members of the phenethylamine
    Phenylethylamine or phenethylamine is a natural monoamine alkaloid, trace amine, and also the name of a class of chemicals with many members well known for psychoactive drug and stimulant effects. Studies suggest that phenylethylamine functions as a neuromodulator or neurotransmitter in the...

     group. (Individuals with anorexia nervosa may seek them to suppress appetite)
  • Stimulants
  • Topiramate (Topamax)
    Topiramate is an anticonvulsant drug. It was originally produced by Ortho-McNeil Neurologics and Noramco, Inc., both divisions of the Johnson & Johnson Corporation. This medication was discovered in 1979 by Bruce E. Maryanoff and Joseph F. Gardocki during their research work at McNeil...

     (as a side effect)
  • Other drugs may be used to intentionally cause anorexia in order to help a patient preoperative fasting
    Fasting is primarily the act of willingly abstaining from some or all food, drink, or both, for a period of time. An absolute fast is normally defined as abstinence from all food and liquid for a defined period, usually a single day , or several days. Other fasts may be only partially restrictive,...

     prior to general anesthesia. It is important to avoid food before surgery to mitigate the risk of pulmonary aspiration
    Pulmonary aspiration
    Pulmonary aspiration is the entry of material from the oropharynx or gastrointestinal tract into the larynx and lower respiratory tract...

    , which can be fatal.
  • Opiates act upon the digestive system and can reduce the physical sensation of hunger in the same way that they reduce physical sensations of pain. They also frequently cause delayed gastric emptying (gastroparesis
    Gastroparesis, also called delayed gastric emptying, is a medical condition consisting of a paresis of the stomach, resulting in food remaining in the stomach for a longer period of time than normal. Normally, the stomach contracts to move food down into the small intestine for digestion. The...

    ) and can sometimes lead to changes in metabolism with long-term use.


  • During the post-operative recovery period for a tonsillectomy or adenoidectomy, it is common for adult patients to experience a lack of appetite until their throat significantly heals (usually between 10-14 days).
  • Altitude sickness
    Altitude sickness
    Altitude sickness—also known as acute mountain sickness , altitude illness, hypobaropathy, or soroche—is a pathological effect of high altitude on humans, caused by acute exposure to low partial pressure of oxygen at high altitude...

  • Significant emotional pain
    Broken heart
    A broken heart is a common metaphor used to describe the intense emotional pain or suffering one feels after losing a loved one, whether through death, divorce, breakup, physical separation or romantic rejection....

     caused by an event (rather than a mental disorder) can cause an individual to temporarily lose all interest in food
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