Nail discoloration, in which the nails appear yellow,white, or green, can result from different infections and conditions of the skin. Fifty percent of cases, discolored nails are a result of infections with common fungi that can be found in the air, dust, and soil. There are many species of fungi that can affect nails. By far the most common, however, is called Trichophyton rubrum. The shade of discoloration ranges from milky white to brown, and additional symptoms of a fungal infection include thickening, spotting and streaking of the nails, This type of fungus has a tendency to infect the skin and is therefore known as a dermatophyte. Pseudomonas is a type of bacteria that infects the nail bed and results in a greenish color to the nails. Red or black (that may sometimes appear bruised) nails may result from a hematoma (a collection of blood) under the nail as a result of trauma (including ingrown toenails).
Fungal infections are normally painless, but excessive thickening of the nails may cause difficulty walking and standing.
Ingrown nails can also cause this type of discoloration. Pseudomonas infections of the nail bed can result in a green tint to the nails. The Centers for Disease Control and Prevention cite antibiotics as the main treatment for pseudonomas infection. To prevent future infections, patients should practice good hand hygiene and avoid contact with poorly maintained hot tubs and pools.
Chronic medical conditions also can affect the appearance of the nails. Podiatry Group of Georgia doctors pay specific attention to nails during a routine examination.