Thanks for writing to health care magic.
Those white patches could be because of pityriasis alba
. It is of course difficult to arrive at a diagnosis with out physically examining your child.
The hypopigmented patches of pityriasis alba become more prominent when a child is exposed to the sun because of increasing pigmentation of the surrounding skin.
Moisturizers and rarely steroids
are used for treatment.
Continue to ask further queries as required.
Hope this helps.