Differential diagnoses - Conditions affecting the tongue

Dr Nigel Stollery explains the differences in characteristic features of diseases of the tongue.

Scarlet fever


  • Strawberry tongue, initially pale with red spots, changing to bright red after a few days
  • Most commonly affects children aged three to 15 years
  • Caused by Group A streptococcus infection
  • Other symptoms include sore throat, headache, vomiting, generally unwell
  • A throat swab can confirm the diagnosis


  • Treatment of choice is a 10-day course of penicillin
  • Although symptoms usually settle after a few days, patients are advised to complete the course to prevent spread and complications
  • Complications are rare and include meningitis, pneumonia and throat abscesses

Geographical tongue


  • Common benign condition affecting 2-3% of the population
  • Characterised by areas of depapillation
  • Area migrates with time
  • Unknown cause
  • May cause a burning sensation
  • No association with oral malignancy


  • Treatment not usually required
  • Condition tends to be chronic

Primary glossitis


  • Soreness of the tongue, often with redness and loss of papillae
  • Swelling may also be present
  • In primary glossitis, the cause is unknown
  • In secondary cases, causes include iron deficiency anaemia, vitamin B deficiencies, infections, allergic reactions


  • Aim is to reduce inflammation
  • Oral hygiene is very important
  • Fluid intake to maintain saliva
  • Investigations are required to exclude secondary causes

Fungal infection


  • Presents with dark, sometimes black, coating on the tongue
  • More common in smokers
  • Tongue may swell and feel sore
  • Taste may also be affected in some cases
  • Differential diagnosis includes candida infections
  • If in doubt, a swab can be taken


  • Topical antifungal drops are helpful
  • Reducing smoking and good oral hygiene are advisable
  • If recurrent, may be related to an immunocompromised state

Dr Stollery is a GP in Kibworth, Leicestershire, and clinical assistant in dermatology at Leicester Royal Infirmary

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