The Ba'al HaTurim wrote (Shemot 8:12) in his description and reason for the plague of lice: "Ve'hach – twice. Here, 'Ve'hach et afar ha'aretz' (and strike the dust of the earth). And elsewhere, 'Ve'hach kaf el kaf' (strike hand to hand) (Yechezkel 21:19). This teaches that the lice were hitting and clapping on their faces and on all their flesh. The reason for the lice is because the Egyptians prevented the Israelites from going to the bathhouses, and as a result, their clothes became filled with lice. Therefore, the Egyptians were stricken with lice."