What causes toenails to turn grey?

* Fungal infection: A fungal infection of the toenail, also known as onychomycosis, is the most common cause of gray toenails. Fungi thrive in warm, moist environments, and they can enter the toenail through small cuts or breaks in the skin.

* Trauma: Injury to the toenail can also cause it to turn gray. This can happen if you stub your toe, drop something heavy on your foot, or wear shoes that are too tight.

* Psoriasis: Psoriasis is a skin condition that can affect the nails. It can cause the nails to become thick, brittle, and discolored.

* Lichen planus: Lichen planus is a rare skin condition that can also affect the nails. It can cause the nails to become thin, brittle, and discolored.

* Certain medications: Some medications, such as chemotherapy drugs and antimalarial drugs, can cause the toenails to turn gray.

* Medical conditions: Certain medical conditions, such as kidney disease, liver disease, and diabetes, can also cause the toenails to turn gray.