All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad (
) is His slave and Messenger.
Wet dreams refer to the discharge of semen during sleep, whether caused by disturbing dreams or otherwise. Hence, if someone enters the state of ihrām for Hajj and then experiences a discharge of semen while asleep, his Hajj is not invalidated, nor is any expiation required of him, for wet dreams have no consequences during Hajj.
In the Kuwaiti Fiqh Encyclopedia, while discussing wet dreams in fasting, it states: "…and likewise, it has no effect on Hajj by consensus…"
Allah Knows best.