Both of your child are suffering from cutis marmorata telengiectetica congenita. In most of the cases it improves with the age as skin also matures with age, but in some it may persist.
In general for the skin lesions there is no specific treatment. But be in touch with dermatologist
as rarely there may be some progress in skin lesions.
In few cases it may be associated with glaucoma
also, so also consult an opthalmologist for early diagnosis if any. Avoid exposure to cold
as it will precipitate the skin lesion.