Geographic Tongue

Geographic Tongue
Characteristic map-like appearance of geographic tongue

• A common condition of the mucous membrane of the tongue characterised by areas of smooth, red depapillation
• Areas can migrate over time
• The name comes from the map-like appearance of the tongue (patches resemble islands of an archipelago)
• Also known as:
  1. Benign migratory glossitis
  2. Erythema migrans
  3. Erythema migrans lingualis
  4. Glossitis areata exfoliativa
  5. Glossitis areata migrans
  6. Lingua geographica
  7. Psoriasiform mucositis
  8. Stomatitis areata migrans
  9. Wandering rash of the tongue
  10. Transitory benign plaques of the tongue

Epidemiology

• Affects 1-2% of the general population
• ♂ > ♀

Clinical Features

• Usually affects the dorsum of the tongue but on occasion can affect the ventrum
• Irregular, pink or red depapillated/atrophic areas
• Red areas are often well-demarcated and surrounded by distinct white/yellowish and slightly raised margins
• There is increased thickness of the intervening filiform papillae.
• Lesions can change in shape, size and location
• A lesion may start as a white patch before depapillation occurs
• Fissured tongue can occur with geographic tongue
• Usually asymptomatic but in a minority can cause sore mouth (pain/burning)
  • Can be worsened by acidic foods (tomatoes/citrus), spice or cheese
  • People with symptoms often report worsening at periods of emotional stress

Differential Diagnosis

Oral candidiasis
Oral Lichen Planus
Trauma
Oral psoriasis (rare)
Herpes simplex
Systemic lupus erythematosus
Oral leukoplakia

Aetiology and Pathogenesis

Aetiology

• Largely unknown but some associations
• 4% of cases are associated with psoriasis (especially pustular psoriasis)
• It is also seen in patients with a food allergy, allergic contact dermatitis, asthma, atopic dermatitis, reactive arthritis, anaemia, hormonal disturbance, emotional stress and in patients with early-stage of type 1 diabetes
• An inverse relationship to smoking and tobacco use has been reported
• Can run in families - raising suggestion of genetic predisposition
• Reports of links with various human leukocyte antigens (increased incidence of HLA-DR5, HLA-DRW6 and HLA-Cw6 and decreased incidence in HLA-B51)
• A hormonal relationship has also been reported

Investigations

• Diagnosis is usually based on history and clinical examination
• Blood tests may be helpful to rule out differentials
• Biopsy and histologic examination of the lesions may also assist in excluding differentials and in reassuring patients of the benign nature of the disorder

Laboratory Investigations

• Routine laboratory tests, including full blood count, sedimentation rate, and levels of C-reactive protein and glucose, are usually normal
• Vitamin B12, ferritin and folate are usually normal

Histology

• Histopathological findings are very similar to those seen in psoriasis
• Characteristic features:
  1. Regular increase of the spinous layer with thickening of the lower portions
  2. Thickening and swelling of papillae
  3. Suprapapillary hypotrophy with occasional presence of a small spongiform pustule
  4. Absence of granular layer
  5. Parakeratosis
  6. Presence of Munro's microabscess
  7. Inflammatory cell infiltration in submucosa (particularly T-lymphocytes, macrophages and neutrophils)

Image from Picciani et al 2016

Management

• Reassurance regarding the benign nature of the condition is usually all that is needed
• Symptomatic cases:
  • Can be advised to avoid irritants in diet
  • Maintain good oral hygiene
  • Topical zinc may be helpful (Zinc sulphate 125mg dispersible tablet [Solvazinc] dissolved in water and used as a mouth rinse - three times a day for 3 months)
  • Benzydamine hydrochloride 1.5mg/mL (0.15%) as mouthwash or spray (sugar-free) can also be used four times daily as instructed (15mL as rinse or four sprays every 1.5 hours as required)

Prognosis and Complications

• No long term sequelae
• May disappear over time but no method exists to predict cases that will

Follow-up

• Appropriate for monitoring and management in primary care