The evidence is the narration of Kaʿb ibn ʿUjrah. He said, “Lice were harming my head, so I was taken to the Prophet ﷺ while the lice were falling across my face. He said, ‘I did not think your hardship had reached what I am now seeing. Do you have a sheep to offer?’ I replied, ‘No.’ Thereupon the verse was revealed: ‘…then a ransom of fasting, or charity, or sacrifice’ (Q 2:196). He explained, ‘That means fasting three days, or feeding six needy people, or slaughtering a sheep.’” This hadith is agreed upon, and the harm in question was not caused by the hair itself but by the lice.

A pilgrim may wash his hair with sidr (lotus leaves) or the like, for in the two Ṣaḥīḥs it is related that the Prophet ﷺ washed his head while in ihram, then ran his hands through his hair, moving them forwards and backwards.

Shaykh Taqī al-Dīn (may Allah have mercy on him) said, “By consensus he may perform a ritual bath for janābah—such as if he has a nocturnal emission while in ihram—and likewise for any other reason.”

Third prohibition: for a male pilgrim to cover his head, because the Prophet ﷺ forbade wearing turbans and burnooses.

The eminent Ibn al-Qayyim (may Allah have mercy on him) stated, “Anything that is contiguous and in contact with the head and is intended to conceal it—such as a turban, hat, skullcap, and the like—is unanimously prohibited.”

It makes no difference whether the covering is customary, like a turban, or unconventional, such as wrapping the head with paper, clay, henna, or a bandage.