I suggest that you go see your primary care doctor
or a dermatologist
about this issue. Since the spots have been persistent for a long time, it is worth while having a doctor look at them so you can know exactly what they are and whether they require treatment.
One possibility is that these white spots are related to eczema
, which is a condition in which the skin becomes red, dry, flaky, and itching. Sometimes, when the eczema flare dies down, it leaves a whitish looking patch, known as post inflammatory hypopigmentation. Post inflammatory hypopigmentation can also occur after any other sort of trauma to the skin, such as a cut or pimple.
Similarly, this could be a fungal infection. One fungal infection in particular, called tinea versicolor, tends to cause patches of skin that are more pale in color than the surrounding skin and that tend to be concentrated on the chest, back and, stomach.
Finally, if the patches are extremely white, rather than just being slightly more pale than the surrounding skin, this might be vitiligo, a condition in which the skin progressively loses its pigmentation.
Start by setting up a visit with your doctor at your earliest convenience!