Man Lā Yaḥḍuruh al-Faqīh
Hadith 11312699 - وَ قَالَ لَهُ مُعَاوِيَةُ بْنُ عَمَّارٍ : اَلْمُحْرِمُ يَحُكُّ رَأْسَهُ فَتَسْقُطُ اَلْقَمْلَةُ وَ اَلثِّنْتَانِ فَقَالَ «لاَ شَيْءَ عَلَيْهِ وَ لاَ يُعِيدُهَا» قَالَ كَيْفَ يَحُكُّ اَلْمُحْرِمُ قَالَ «بِأَظْفَارِهِ مَا لَمْ يُدْمِ وَ لاَ يَقْطَعْ شَعْرَهُ».
Hadith.2699 - Mu'awiyah ibn Ammar asked him about a person in the state of ihram who scratches their head, causing one or two lice to fall off.
Imam (as) said: "There is no penalty upon them, nor do they need to replace the lice."
He asked: "How should the person in ihram scratch?"
Imam (as) replied: "With their nails, as long as they do not cause bleeding or cut any hair."