It was narrated from Ka’b bin ‘Ujrah, that he was with the Messenger of Allah صلی اللہ علیہ وآلہ وسلم in Ihram and he suffered an infestation of head lice. The Messenger of Allah صلی اللہ علیہ وآلہ وسلم commanded him to shave his head and told him: “Fast for three days, or feed six poor persons two Mudds each, or sacrifice a sheep. Whichever one of these you do will be sufficient for you.” (Sahih)