Nail changes can be produced by a number of conditions. Non-infectious causes include psoriasis, lichen planus etc. Inflammation of the surrounding skin can also lead to changes in the nail. Fungi of various kinds can affect a previously damaged skin (by some other disorder) or can affect a perfectly normal skin. In the former situation, eradication of the fungus will not make the nail OK. Fungal nail infections due to dermatophytes are generally easier to treat; others are more difficult. Green discoloration is usually not a feature of dermatophyte infection.