1. Leviticus 13:20 (ESV)
  2. Exposition

What does the white hair on the boil mean?

Leviticus 13:20 (ESV)

20 And the priest shall look, and if it appears deeper than the skin and its hair has turned white, then the priest shall pronounce him unclean. It is a case of leprous disease that has broken out in the boil.

If it has a deep infection and white hair, then it is a serious skin disease. The man is immediately declared unclean by the priest.