TETTER (בֹּ֥הַק; ἀλφός). Tetter is a term used (pemphigus), crusted tetter (impetigo), dry tetter (crusty eczema), and scaly tetter (psoriasis).
As used in Leviticus 13:39, it does not mean any of these diseases, nor does it mean freckles, as tr. in the KJV. The men and women reporting had white patches of skin. Diagnosis was necessary because a white patch is occasionally an early symptom of leprosy.
When declared non-contagious, it was prob. vitiligo—irregular areas of de-pigmented skin. The bleached out areas spread centrifugally, sometimes involving the hair and producing white streaks. The cause is unknown. It is disfiguring, but not dangerous.
Egyptian women were acquainted with vitiligo. They are said to have restored some of the normal color by chewing plants found along the banks of the Nile. Staining the white patches was also resorted to, as it is in our own generation.
International Standard Bible Encyclopedia (1915)
The term "freckled spot" in the King James Version is thus rendered in the Revised Version (British and American). The eruption referred to in Le 13:39 is a pale white spot on the skin. This is described by Gorraeus as an eruption arising from a diseased state of the system without roughness of skin, scales or ulceration. It did not render the sufferer unclean, although it is difficult of cure. The disease is commonly known by its Latin name vitiligo. Pliny recommended the use of capers and lupins to remove it.
See Freckled Spot; Leprosy.