Welcome to Healthcaremagic.
I do not know you age , hence i could not be specific.
As most of the skin conditions occur due to influence of hormones.The hormones alter the sebaceous secretions and subsequently render the skin prone to damage by free radicals or sunlight.
The exact cause of the problem can be made out when the white spots
you have are examined and correlated with your age and general physical condition.
Wish you good health.