White discoloration spots on the skin

Hi. I am 54 and about 6 months ago I noticed a skin discoloration in the area of the left arm pit and very recently I found the same colorless spot in the throat right under my chin. These spots are odd shaped about 2" long 1" wide and look paler than the surrounding skin. There are no symptoms, juts a cosmetic effect so far. What may be the cause for this condition?