John Calvin Commentary Leviticus 13:29

"And when a man or woman hath a plague upon the head or upon the beard," — Leviticus 13:29 (ASV)

If a man or woman. What is spoken of here is not the baldness that so often occurs in old age; but that loss of hair, which is the consequence of leprosy, is distinguished from any other, whose cause may be some ailment, and which nevertheless does not defile a person. But, since some kinds of baldness do not differ so greatly at first sight from leprosy—such, for instance, as ophiasis and alopecia⁸—it is therefore necessary to distinguish them.

⁸ “Ophiasis, (ὀφιασις Gr.,) a disease, in which the hair grows thin, and falls off, leaving the parts smooth and winding like the folds of a serpent.”,) a disease, in which the hair grows thin, and falls off, leaving the parts smooth and winding like the folds of a serpent.”