Ka'b ibn Ujrah RA

Ka'b ibn Ujrah RA was among the Companions who set out for Umrah in ihram and were halted at Hudaybiyyah in 6 AH. He was so badly infested with lice that it could be seen on his face. When the Prophet ﷺ saw him, he asked why he had not told him it was this bad, and told him to shave his head and pay a fidyah, a compensation. From his case, scholars learn that a pilgrim may break the restrictions of ihram for a genuine medical need, provided the fidyah is paid.