Loss of appetite - red flag symptoms

Red flags in patients with loss of appetite, possible causes and further investigations to consider.

Red flag symptoms

  • Significant unintentional weight loss
  • New-onset dyspepsia, age more than 55
  • Dysphagia
  • Symptoms raising suspicion of malignancy
  • Persistent low mood
  • Features suggesting alcohol dependence
  • Mini–mental state examination (MMSE) score, or equivalent, suggesting cognitive impairment.

Loss of appetite may only emerge when you ask about other presenting symptoms. Loss of appetite has a broad differential diagnosis, so a focused history is crucial.


It is important to understand what the patient means by ‘loss of appetite’. Try to determine what a normal appetite is for them and over what time their appetite has decreased. Loss of appetite may not have been noticed by the patient, but by friends or family.

Establish why the patient thinks they have lost their appetite and whether anything has changed in their life that may have led to this. Find out why the patient presented with this problem now.

Important features in the history include:

  • when the loss of appetite began
  • what the patient is eating on a daily basis
  • whether there are associated physical symptoms that stop the patient eating (for example, dysphagia, odynophagia, epigastric pain or reflux).
Possible causes of loss of appetite
  • Acute or chronic bacterial or viral infections
  • Metabolic problems, such as hypothyroidism
  • Malignancy
  • Gastrointestinal conditions, such as gastritis, duodenitis or oesophagitis
  • Psychiatric disorders, such as depression, anxiety, alcohol or drug dependence
  • Cognitive impairment

If the history of loss of appetite is short-lived and there are symptoms of an acute infection then explain to the patient that their appetite will return as the infection subsides.

Coeliac disease may cause loss of appetite and change in bowel habit.

Respiratory symptoms may be relevant. Patients, particularly children, with respiratory tract infections often report appetite loss.

Loss of appetite with a history of persistent night sweats will require further investigation to exclude the possibility of chronic infection, HIV or haematological malignancy. Tuberculosis is a possible cause. It is not a common diagnosis in the UK but prevalence will be higher in certain parts of the country.

Symptoms pointing to a psychological aetiology may include persistent low mood, early morning awakening, weight loss, anergia, loss of concentration, anhedonia, helplessness and hopelessness. If there is evidence of depression a risk assessment is essential. Ask how much the patient drinks, as alcohol-dependent patients have reduced appetites.

It is common to see patients with advanced dementia develop loss of appetite. So if there are features of cognitive impairment, such as significant memory disturbance affecting function, referral to the memory clinic may be necessary.


Observe the patient for signs of cachexia. Note any evidence of cognitive impairment or flat affect. The remaining examination will be guided by the history. A full gastroenterological examination may be required. If the patient has odynophagia then examination of the neck and throat may be necessary.

It is important to weigh the patient and calculate a BMI. Compare this with any previous values in their records.


Further investigations include:

  • blood tests
  • Helicobacter pylori stool antigen (if evidence of dyspepsia)
  • chest X-ray if clinically indicated
  • ultrasound scan of the abdomen if indicated
  • depression screening
  • an alcohol-use questionnaire, and
  • mini mental state examination (MMSE), or equivalent, cognitive test.

Reflux disease is associated with loss of appetite and if this is of new onset in patients over the age of 55 years, then urgent endoscopy may be necessary.

Lower GI investigations may be required to exclude malignancy. If malignancy is suspected refer under the two-week rule.

  • Dr Pipin Singh is a GP in Northumberland

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This is an updated version of an article first published in July 2012.

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