Exodus 4:6

and Aaron spoke all the words which Yahweh had spoken to Moses. He then did the signs in the sight of the people.

then the priest shall look at it. And if the hair in the bright spot has turned white and it appears to be deeper than the skin, it is leprosy; it has broken out in the burn. Therefore, the priest shall pronounce him unclean; it is an infection of leprosy.

But the cloud withdrew from over the tent, and behold, Miriam was leprous, as white as snow. And Aaron turned toward Miriam, and behold, she was leprous.

“Thus the leprosy of Naaman shall cling to you and to your seed forever.” So he went out from his presence a leper as white as snow.