Onychomycosis is a fungal infection that can result in thick, brittle, white, or yellow toenails.
Damage to the toenail can prevent it from growing normally, leaving white streaks or patches behind.
Pale or white toenails can result from deficits in zinc, protein, or vitamin B12.
Some people may experience an allergic response to nail products, turning their toenails white.
Psoriasis of the nails is a persistent skin disorder that can leave white patches or discolouration on the toenails.