Mottled skin in newborn babies is usually the result of cutis marmorata. It is a typical physiological response to cold temperatures and does not require treatment. Babies will usually grow out of cutis marmorata within a few weeks or months, but it can persist into adulthood. Rarely, mottled skin in babies can occur because of cutaneous marmorata telangiectatica congenita, a genetic condition that causes blood vessels to form differently than usual.