39 the priest is to examine them, and if the spots are dull white, it is a harmless rash that has broken out on the skin; they are clean.

Read Leviticus 13:39 Using Other Translations

Then the priest shall look: and, behold, if the bright spots in the skin of their flesh be darkish white; it is a freckled spot that groweth in the skin; he is clean.
the priest shall look, and if the spots on the skin of the body are of a dull white, it is leukoderma that has broken out in the skin; he is clean.
the priest must examine the affected area. If he finds that the shiny patches are only pale white, this is a harmless skin rash, and the person is ceremonially clean.