A fungal infection of the nail is known as onychomycosis and is caused by specific yeasts or molds.
It can affect one or more toenails or fingernails – most often involving the big toenail or little toenail. The nail may have an opaque streak at one side, scaling under the nail, a crumbly edge, white patches or yellow spots
Treatment can involve topical antifungal medication, oral antifungal medication or combination therapy. Some success has also been seen with laser treatment or photodynamic treatment.
Psoriasis of the nails typically occurs in patients who suffer from psoriasis of the skin.
The exact cause is not known but the immune system is involved and appears to be overactive and causing inflammation.
Symptoms can vary depending on which part of the nail is affected, but can include yellow-red discoloration in the nail bed, oil-like drops under the nail, a white nail bed or weakened nail bed.
There is no known cure, treatment depends on the site and severity but can include topical solutions, steroid injections, systemic treatments or UVA treatment. The condition may also clear by itself.