How to diagnose white spots on the nails
Think about what has happened to your hands lately. If the area around the white spot appears red or bruised, it is possible that the nail was injured. This should heal on its own. If the white spots appear on the toenails, consider your footwear. White spots are common for those who run, and are often caused by tight or ill-fitting sneakers.
Consider your diet. White spots on the nail may indicate an iron or zinc deficiency. If you do not consume much zinc and iron through foods such as meat, enriched bread, oatmeal, mushrooms and/or spinach, consider adding a multivitamin to your diet. If the white spots do not go away after using a multivitamin for a few weeks, consult a doctor.
Evaluate any joint pain you may feel while exercising or at rest. White spots may indicate arthritis and should be evaluated by a doctor.
Look at the location of the white spots. If the white spot appears near the top of the nail where the nail meets the skin, it may indicate a fungal infection. Contact a doctor for treatment.
Be aware that in very rare cases, white spots on the nail may indicate poisoning. If all other factors have been ruled out, speak with a doctor about your concerns.