White spots usually develop because you've hit your nails against something. Greenish Nails Greenish nails are usually a result of a localized fungal infection. If you find greenish nails under your nail polish, consult your health care provider as there are treatments for this kind of fungal infection. Ridges Ridges can appear either vertically or horizontally. Horizontal ridges called Bean's lines, can result from severe stress.
Vertical lines can indicate poor nutrition, or iron deficiency.
Sometimes your nail looks like it's going to literally lift off from the nail bed. It's scary and could be a sign of psoriasis, a skin disorder. Or it might be because your hands are spending too much time in water, detergents or soaps. If this is caused from having your hands in water too much, you might want to consider wearing rubber gloves when washing dishes or doing house work. Use nail polish remover with caution.