Problems in the Mouth

Authored by , Reviewed by Dr Helen Huins | Last edited | Certified by The Information Standard

This article is for Medical Professionals

Professional Reference articles are designed for health professionals to use. They are written by UK doctors and based on research evidence, UK and European Guidelines. You may find the Mouth Care article more useful, or one of our other health articles.

This article is a general overview of a large topic, with links to other resources to allow further enquiry.

The differential diagnoses for the clinical scenarios presented are far from complete and other diagnoses may need to be considered, depending upon the specific details of a patient's presentation. It should, however, be useful as a quick reference diagnosis guide to the conditions seen in primary care that commonly cause oral problems.

Where there is doubt as to the nature of an oral pathology, seek further advice from a dental general practitioner, oral physician, oral surgeon, or ENT specialist. If you suspect that the oral problems may relate to systemic disease, refer to a general physician or the relevant speciality - eg immunology.

Referral of patients with mouth ulcers

It is important not to miss a diagnosis of oral cancer in its early stages. See separate article Mouth and Tongue Cancer.

Referral should be to an oral medicine department or to an oral and maxillofacial department.

Refer urgently:

  • If there is suspected malignancy (urgently): persistent symptoms (>3 weeks), unexplained bleeding, painful or swollen red or white patches.

Refer non-urgently:

  • If the patches are not painful, not swollen or not bleeding.
  • If there is a suspected underlying cause for aphthous-like ulcers.
  • If ulceration is especially disabling, painful or recurrent (despite a benign diagnosis).

NB: if there is a localised dental cause for the ulceration - refer to a dentist.

'Soreness' in the mouth is usually due to mucosal inflammation and/or ulcer formation. Mouth ulcers are extremely common and have a number of causes.

For more detail see separate article Oral Ulceration.

Aphthous ulcers

  • These are also referred to as canker sores, aphthous stomatitis, recurrent aphthous stomatitis (RAS), recurrent oral ulceration (ROU).
  • This condition tends to start in childhood or adolescence. There are recurrent small, round or ovoid ulcers with circumscribed margins, erythematous haloes and yellow or grey floors.
  • They affect at least 20% of the population and their natural course is one of eventual remission. They are often recurrent.[1]

Herpetic disease

Primary infection of herpes simplex virus type 1 (HSV-1) tends to occur in children under 5 years old. Infection occurs through intimate contact (eg, saliva) and viral shedding goes on from 4-60 hours following onset of symptoms (incubation period is 3-7 days). It may well be asymptomatic but patients who do present tend to do so with gingivostomatitis in children and as pharyngotonsillitis or a mononucleosis (glandular fever) type of illness in adults. There may be prodromal symptoms including fever, nausea, malaise, headache and irritability. Symptoms generally last for one to two weeks. This self-limiting condition can be adequately managed symptomatically with:

  • Analgesia (eg, paracetamol).
  • Good fluid intake.
  • Avoidance of salty or acidic foods.
  • Topical benzydamine, which may be helpful for pain relief.
  • Chlorhexidine mouthwash, which should minimise secondary infection.
  • Lip barrier preparations (eg, Vaseline®) can be helpful.

Steps should be taken to minimise transmission:

  • Avoid touching the lesions - if this is necessary, such as after applying lip cream, wash hands afterwards.
  • Avoid kissing and oral sex until the lesions have healed.
  • Avoid sharing items which come into contact with the lesions.
  • If children are well, they do not need to be excluded from school or nursery.

Oral antivirals should be considered for immunocompetent individuals with severe gingivostomatitis.[2]However, it is recommended that specialised advice should be sought before prescribing antivirals.[3]Referral is appropriate for immunocompromised or pregnant patients, if there is a risk of dehydration or if ulcers do not heal within 14 days.

Cold sores
This is the reactivation of latent HSV-1 which has remained dormant in the trigeminal ganglion. Cold sores are common and result in recurring symptoms in 20-40% of young adults who are seropositive for HSV-1.

  • This is usually a self-limiting condition (7-10 days) which can be managed symptomatically as with gingivostomatitis (above) with the same precautions needed to minimise the risk of transmission.
  • Topical antiviral treatment is widely available and may affect the course of the current episode if applied in the prodromal phase but preparations do not cure the patient or prevent further episodes. Prophylactic use is ineffective.
  • Refer pregnant women (particularly towards the end of the pregnancy) and immunocompromised patients, for specialised advice on management.

Oral candidiasis

This is a fungal infection of the oral mucosa, usually caused by Candida albicans, or sometimes by other Candida spp. Factors predisposing to oral candidiasis:


  • Pain - may make eating and drinking difficult.
  • Altered sense of taste - sometimes.
  • May be asymptomatic.

There are several clinical forms of oral candidiasis (see separate article Candidiasis).

Burning mouth syndrome (BMS)[4]

This idiopathic condition is characterised by a burning sensation in the tongue or other parts of the mouth in the absence of medical or dental causes:

  • Exclude local and systemic factors (such as xerostomia, infections, allergies, ill-fitting dentures, hypersensitivity reactions and hormone and vitamin deficiencies) before diagnosing BMS.
  • Dryness and taste disturbance are also often present.
  • Symptoms are sometimes relieved by eating and drinking (unlike mouth ulcers, which are more painful on eating).
  • It is more common in older adults (past middle age).
  • The cause is unclear - it may be a form of neuropathy.
  • Treatment and management of this condition are very difficult. Despite not being accompanied by evident organic changes, BMS can significantly reduce the quality of life for these patients.

Geographic tongue (benign migratory glossitis)[5]

This is a common idiopathic condition affecting up to 10% of children and adults:

  • It presents with map-like red areas (hence its name) of atrophy of filiform tongue papillae. The areas and patterns may change rapidly (over hours). The tongue is often fissured.
  • Lesions may be asymptomatic but can cause soreness.
  • The cause is unknown.
  • One study has shown that that geographic tongue may be an oral manifestation of psoriasis.[6]
  • Diagnosis is based on the appearance. No treatment is necessary.

Causes of sore mouth or mouth ulcers to consider in children are:

  • Dental disease.
  • Kawasaki disease where the child has fever and irritability, particularly if there is a rash, erythema/desquamation of the extremities, conjunctivitis or cervical lymphadenopathy.
  • Hand, foot and mouth disease is another important acute cause of sore mouth in children.
  • Herpetic gingivostomatitis or oral candidiasis - as described under 'Causes of mouth ulcers', above.
  • Cancrum oris - this is a serious condition characterised by a rapid, painless and extensive necrosis of the oral cavity that can involve the cheek, nose, palate and bones. It almost always occurs in the context of poor oral hygiene and in developing countries. It may be preceded by excessive salivation, malodour from the mouth, grey discoloration and gingival ulcer formation. See separate article Cancrum Oris (Noma).

NB: persistent swellings in the mouth should be referred for an oral surgery opinion to avoid missing oral cancers.

Swellings related to salivary glands:

  • Mucocele - a swelling of the inner surface of the mouth or ventral surface of the tongue. It is due to obstruction or rupture of a small salivary gland duct. It may have a bluish, translucent colour. When it occurs on the floor of the mouth it is known as a ranula.
  • Swellings of the sublingual salivary glands may be felt in the floor of the mouth. See separate article Salivary Gland Disorders.

Other swellings in the mouth may be due to a wide range of conditions. The list below outlines some of the more common causes:

  • Non-pathological - unerupted teeth, pterygoid hamulus, parotid papillae, lingual papillae.
  • Developmental - haemangioma, lymphangioma, maxillary and mandibular tori (bony exostoses), hereditary gingival fibromatosis, Von Recklinghausen's neurofibromatosis.
  • Inflammatory - abscess, granulomatosis, sarcoidosis, pyogenic granuloma, Wegener's granulomatosis.
  • Traumatic - epulis, fibro-epithelial polyp, denture granulomas.
  • Cystic - eruption cysts, developmental cysts, infective cysts, ranula (mucocele of the minor salivary glands).
  • Fibro-osseous - fibrous dysplasia, Paget's disease of bone.
  • Hormonal - pregnancy epulis, pregnancy gingivitis, oral contraceptive pill gingivitis.
  • Drugs - phenytoin, calcitonin, calcium-channel blockers.
  • Tumours - benign and malignant.
  • Haematological - leukaemias, lymphomas.
  • Miscellaneous - angio-oedema, amyloidosis.

Red lesions of the oral mucosa are usually inflammatory in nature but may also be malignant, especially erythroplasia. The table below lists some important causes of red lesions of the oral mucosa.

Common and important cause of red lesions in the mouth

Localised red patches

  • Candidiasis.
  • Lichen planus.
  • Erythroplasia/erythroplakia:
    • This is a premalignant or malignant lesion of the oral mucosa.
    • Although relatively rare, this is an important diagnosis not to miss. It tends to affect older patients above 60 years of age. Smoking is a risk factor.
    • The lesion looks red and velvety. It usually affects the mouth, the ventrum of the tongue, or the soft palate.
    • If suspected, refer to oral surgery for biopsy. These lesions have a high potential for malignancy.[7]
  • Angiomas, purpura or telangiectasias.
  • Burns and local trauma.
  • Kaposi's sarcoma.

Widespread redness
This may also be caused by many of the above, but also consider:

Common and important cause of white lesions in the mouth

Infective causes

  • Candidiasis.
  • Hairy leukoplakia (below).
  • Syphilitic keratosis.[8]
  • Human papillomavirus.

Mucocutaneous conditions


  • This term was formerly used to describe all white lesions of the oral mucosa, but is now given to those cases of unknown cause or those cases that are considered to be premalignant.[8]
  • Malignant transformation rates of oral leukoplakia range from 0.13-17.5%.[9]
  • Referral for biopsy is required to exclude or diagnose malignancy. However, most white lesions in the mouth are relatively benign keratoses caused by friction from teeth, cheek biting or tobacco smoking.
  • Various treatments have been used to try to encourage resolution of leukoplakic lesions and prevent malignant transformation, but their efficacy is unproven.
  • Photodynamic therapy and cryotherapy are alternatives for the traditional surgical treatment of oral leukoplakia.[10]
  • Carbon dioxide laser ablation is also used for some cases.[11]

Hairy leukoplakia

  • This is a white, asymptomatic lesion, usually on the lateral margin of the tongue.
  • It is associated with the Epstein-Barr virus and with immunocompromise.
  • The lesions vary in appearance from smooth, flat, small lesions to irregular 'hairy' or 'feathery' lesions with prominent folds or projections, located on the margins, dorsal or ventral surfaces of the tongue or on buccal mucosa.
  • Treatment options include systemic antiviral therapy (eg, aciclovir 800 mg five times a day), topical therapy with podophyllin or retinoic acid, or cryotherapy.

For more details on both of these conditions see separate article Leukoplakia.

Oral lichen planus

This inflammatory condition commonly presents in older patients, with white patches affecting the mucosa of the mouth or tongue bilaterally. Involvement of the gums with oral lichen planus is known as 'desquamative gingivitis'.

  • Refer for biopsy and follow-up to exclude or monitor for malignancy.
  • There is a small risk of developing malignancy, so long-term follow-up is required.[12]
  • Erosive, atrophic, ulcerative lesions require long-term treatment because of inflammation and severe pain.
  • Topical steroids, immunosuppressants, aloe vera, hyaluronic acid and antifungals have all been shown to be beneficial as treatment for this condition. They enhance healing, improve signs and symptoms of lesions and therefore improve the quality of patients' lives. Topical treatment is recommended mainly because of minimal side-effects.[13]

See separate article Lichen Planus.

  • Blue/purple patches may be haemangiomas (will blanch with pressure), Kaposi's sarcoma (will not blanch) or purpura/ecchymoses (non-blanching, usually smaller lesions). Other rarer causes include heavy-metal toxicity or Peutz-Jeghers syndrome.
  • Brown or black lesions may be caused by staining from fillings (so-called amalgam tattoo) or naevi (freckles) but could rarely be due to a melanoma, so referral for biopsy should be considered.
  • If the tongue is furred and brown/black and/or appears hairy (particularly on its posterior portion), this is likely to be due to poor oral hygiene. It can be a problem in edentulous patients, those with a soft diet, those who smoke, those who are fasting or ill or are using antimicrobials or chlorhexidine long-term. At its extreme this condition is termed black, hairy tongue. The condition is treated by improving oral hygiene, brushing the tongue or using a tongue scraper, increasing dietary fruit and roughage (pineapple is useful) and the use of sodium bicarbonate mouthwash.
  • Generalised pigmentation of the oral mucosa can be a normal feature in people of dark-skinned races. Certain medications (eg, phenothiazines, zidovudine, minocycline) and smoking can rarely cause it, as can Addison's disease or ectopic production of adrenocorticotrophic hormone (ACTH) - eg, by carcinoma of bronchus.

Also known as xerostomia, this is characterised by a dry mouth sensation ± difficulty in speaking or swallowing, due to thick or sticky saliva. Individuals may also complain of halitosis. A wide range of conditions may cause this problem. Relatively common causes are listed below:

  • Psychogenic causes including BMS (see under 'Other causes of sore mouth', above).
  • Age-related.
  • Anticholinergic medication (particularly tricyclic antidepressants).
  • Various other medication, including diuretics.
  • Sjögren's syndrome.
  • Head and neck radiotherapy.
  • Any cause of salivary gland dysfunction (see separate article Salivary Gland Disorders).

Treatment is with hydrating agents to provide moisture and comfort - usually gels or sprays. Good dental care is important because dry mouth predisposes individuals to tooth decay.

For more information see separate article Dry Mouth (Xerostomia).

  • Common causes are poor oral hygiene and gingivitis/periodontal disease.
  • Halitosis is also commonly caused by gastro-oesophageal reflux disease and this needs to be investigated and managed appropriately.[14]
  • Other possible causes are acute or occult illness, including chest infection, bronchiectasis, lung abscess, appendicitis, gastroenteritis, undiagnosed diabetes mellitus or fetor hepaticus from liver disease.
  • Possible treatments, depending on the cause, are smoking cessation, better oral hygiene, use of antiseptic mouthwashes and regular dental follow-up.

See separate article Halitosis for further information.

These are best dealt with by a dental general practitioner. However, current NHS dentistry provision is increasingly patchy, so such problems are presenting to medical primary care and emergency departments more frequently. See separate article Some Dental and Periodontal Diseases for more detail.

Further reading and references

  1. ; Recurrent aphthous stomatitis: a review. J Oral Pathol Med. 2012 Sep41(8):577-83. doi: 10.1111/j.1600-0714.2012.01134.x. Epub 2012 Mar 13.

  2. ; Herpetic gingivostomatitis with severe hepatitis in a previously healthy child. J Microbiol Immunol Infect. 2012 Aug45(4):324-5. doi: 10.1016/j.jmii.2011.11.014. Epub 2012 May 7.

  3. ; NICE CKS, September 2012 (UK access only)

  4. ; Burning mouth syndrome. Dent Clin North Am. 2013 Jul57(3):497-512. doi: 10.1016/j.cden.2013.04.010.

  5. ; Common tongue conditions in primary care. Am Fam Physician. 2010 Mar 181(5):627-34.

  6. ; Geographic stomatitis: an oral manifestation of psoriasis? J Dermatol Case Rep. 2012 Dec 316(4):113-6. doi: 10.3315/jdcr.2012.1118.

  7. ; Challenges in predicting which oral mucosal potentially malignant disease will progress to neoplasia. Oral Dis. 2014 Jan20(1):1-5. doi: 10.1111/odi.12208.

  8. ; Potentially malignant disorders of the oral cavity: current practice and future directions in the clinic and laboratory. Int J Cancer. 2014 Jan 31. doi: 10.1002/ijc.28754.

  9. ; Oral premalignant lesions: from a clinical perspective. Int J Clin Oncol. 2011 Feb16(1):5-14. doi: 10.1007/s10147-010-0157-3. Epub 2011 Jan 12.

  10. ; Comparison of cryotherapy and photodynamic therapy in treatment of oral leukoplakia. Photodiagnosis Photodyn Ther. 2012 Jun9(2):148-55. doi: 10.1016/j.pdpdt.2011.12.007. Epub 2012 Jan 14.

  11. ; Cryogun cryotherapy for oral leukoplakia. Head Neck. 2012 Sep34(9):1306-11. doi: 10.1002/hed.21912. Epub 2011 Nov 15.

  12. ; The malignant transformation of oral lichen planus and oral lichenoid lesions: A systematic review. J Am Dent Assoc. 2014 Jan145(1):45-56. doi: 10.14219/jada.2013.10.

  13. ; Topical Application of Drugs Used in Treatment of Oral Lichen Planus Lesions. Adv Clin Exp Med. 2013 Sep-Oct22(6):893-898.

  14. ; Gastroesophageal reflux, dental erosion, and halitosis in epidemiological surveys: a systematic review. Eur J Gastroenterol Hepatol. 2013 Feb25(2):135-41. doi: 10.1097/MEG.0b013e32835ae8f7.

hi,im not sure if ive always had this but one of my tonsils is slightly larger then the other! too look at it in the mirror it doesnt look much bigger at all, but when i take a photo its clearly...

Health Tools

Feeling unwell?

Assess your symptoms online with our free symptom checker.

Start symptom checker