Muwatta Imam Malik Book of Hajj, Hadith 246

Yahya related to me from Malik from Abd al-Karim ibn Malik al- Jazari from Abd ar-Rahman ibn Abi Layla from Kab ibn Ujra that one time he was with the Messenger of Allah ﷺ in ihram, and he was suffering from lice on his head. The Messenger of Allah ﷺ told him to shave his head, saying, "Fast three days, or feed six poor people, two mudds for each person, or sacrifice a sheep. If you do any of those it will be enough for you."

حَدَّثَنِي يَحْيَى، عَنْ مَالِكٍ، عَنْ عَبْدِ الْكَرِيمِ بْنِ مَالِكٍ الْجَزَرِيِّ، عَنْ عَبْدِ الرَّحْمَنِ بْنِ أَبِي لَيْلَى، عَنْ كَعْبِ بْنِ عُجْرَةَ، أَنَّهُ كَانَ مَعَ رَسُولِ اللَّهِ ﷺ مُحْرِمًا فَآذَاهُ الْقَمْلُ فِي رَأْسِهِ فَأَمَرَهُ رَسُولُ اللَّهِ ﷺ أَنْ يَحْلِقَ رَأْسَهُ وَقَالَ " صُمْ ثَلاَثَةَ أَيَّامٍ أَوْ أَطْعِمْ سِتَّةَ مَسَاكِينَ مُدَّيْنِ مُدَّيْنِ لِكُلِّ إِنْسَانٍ أَوِ انْسُكْ بِشَاةٍ أَىَّ ذَلِكَ فَعَلْتَ أَجْزَأَ عَنْكَ " .