Hazrat Aisha (Radiallahu anha) says, "I used to comb the hair of Sayyidina Rasulullah (Sallallahu alaihe wasallam), even when I was in the state of menstruation." (PT)
English reference (PT): Book 4, Hadith 31 (PT)
Arabic reference (PT): Book 4, Hadith 32 (PT)