What are white discolorations on a tongue but not thrush?

White discolorations on the tongue that are not thrush can be caused by a variety of factors, including:

- Leukoplakia: This is a condition characterised by the development of white patches or plaques on the tongue that cannot be scraped off. Leukoplakia can be caused by smoking, tobacco use, alcohol consumption, or chronic irritation from dentures.

- Geographic tongue: This is a harmless condition characterised by red, smooth patches on the tongue that are surrounded by a white border. The patches can change shape and location over time.

- Hairy tongue: This condition is caused by an overgrowth of filiform papillae, which are the small, hair-like structures on the tongue. Hairy tongue can be caused by poor oral hygiene, smoking, or certain medications.

- Oral candidiasis: This is a fungal infection of the mouth that can cause white patches to develop on the tongue. Oral candidiasis is also known as thrush.

- Lichen planus: This is a chronic inflammatory condition that can affect the skin, nails, and mouth. When it affects the mouth, lichen planus can cause white patches to develop on the tongue.

- White sponge nevus: This is a rare developmental disorder that can cause white patches to develop on the tongue and mucous membranes of the mouth. White sponge nevus is usually present from birth and does not cause any symptoms.