פירוש על נגעים 3:5

הנתקים (bald/blanched spot on the head or on the beard) – plagues that are on the head or on the beard are called נתקים.

Head or beard ( negaim become unclean for two weeks and by one of the following two signs: by yellow thin hair or by a spreading. Today's mishnah deals with negaim that are found on the head or beard. This topic is dealt with directly in Leviticus 13:29. Such negaim are identified by a thin yellow hair (Leviticus 13:30) or by spreading.

בשער צהוב דק בתחלה (with thin golden hair at the beginning) – if at the beginning golden hair appeared on him, he (i.e., the Kohen) declares him to be a certified leper.

"By yellow thin hair" in the beginning, at the end of the first week, at the end of the second week, or after they have been pronounced clean. The yellow thin hair can serve as an identifying mark at the beginning of the examination period, or at the end of any of the weeks of isolation.

צהוב – similar to gold.

"Or by a spreading," at the end of the first week, at the end of the second week or after they have been pronounced clean. The spreading must occur at the end of at least one of the weeks.

בסוף שבוע ראשון ובסוף שבוע שני – if at the end of the first week it spread or their appeared on him golden hair, he (i.e., the Kohen) declares him to be a certified leper. But if not, he isolates him/shuts him up, for the second [week], but if at the end of the second week it spreads, or golden hair appears, he (i.e., the Kohen) declares him to be a certified leper. But if not, he releases him. But if after the release, it spread, or golden hair appears, he (i.e., the Kohen) declares him to be a certified leper.

They become unclean for two weeks which are only thirteen days. Same as mishnah three.