A. Yes, student visa holders are allowed to leave the USA only if they have permission from the DSO (Desgnated School Official) of their respective US universities or colleges. Only upon the signatures and permission of the DSO can student visa holders leave the US and re-enter the US territory, if already holding the student visa in the USA and ofcourse if it is valid. WIthout these permissions, applicants cannot exit or enter the USA for whatsoever reasons, thus abiding by rules while holding the visa is must.