Halacha

הלכה א
מִי שֶׁהָיְתָה בּוֹ בַּהֶרֶת וְהֻחְלַט בְּאֶחָד מִסִּימָנֵי טֻמְאָה בֵּין בַּתְּחִלָּה בֵּין אַחַר הֶסְגֵּר. אוֹ שֶׁהֻסְגַּר וְאַחַר כָּךְ פָּרְחָה הַצָּרַעַת בְּכֻלּוֹ וְנֶהְפַּךְ לָבָן. בֵּין שֶׁנֶּהְפַּךְ מִתּוֹךְ הֶסְגֵּר בֵּין מִתּוֹךְ הֶחְלֵט הֲרֵי זֶה טָהוֹר. אֲבָל אִם הֻסְגַּר וְלֹא נוֹלַד לוֹ סִימַן טֻמְאָה וְנִפְטַר וּלְאַחַר הַפִּטּוּר פָּרְחָה הַצָּרַעַת בְּכֻלּוֹ הֲרֵי זֶה טָמֵא מֻחְלָט:
כסף משנה
1.
When a person had a baheret and - whether at the outset or after isolation - he was definitively deemed as impure because of one of the signs of impurity or he was isolated and then the tzara'at spread over his entire body and his skin turned white, he is pure. This applies whether it turned while he was isolated or after he was deemed definitively as impure.
If, however, he was isolated and no sign of impurity emerged and as a result, he was released from the inspection process, but after being released, the tzara'at covered his entire body, he is deemed definitively impure.

הלכה ב
הַבָּא בַּתְּחִלָּה וְהוּא כֻּלּוֹ הָפַךְ לָבָן. אִם הָיְתָה בּוֹ מִחְיָה אוֹ שְׁתֵּי שְׂעָרוֹת לְבָנוֹת מַחְלִיטִין אוֹתוֹ. אִם אֵין שָׁם סִימַן טֻמְאָה מַסְגִּירִין אוֹתוֹ שָׁבוּעַ רִאשׁוֹן. נוֹלַד לוֹ שֵׂעָר לָבָן אוֹ מִחְיָה מַחְלִיטוֹ. לֹא נוֹלַד בּוֹ כְּלוּם מַסְגִּירוֹ שָׁבוּעַ שֵׁנִי. לֹא נוֹלַד לוֹ סִימַן טֻמְאָה הֲרֵי זֶה טָהוֹר. שֶׁדִּין בַּהֶרֶת זוֹ הַגְּדוֹלָה כְּדִין הַקְּטַנָּה. הֶחְלִיטוֹ בְּשֵׂעָר לָבָן שֶׁנּוֹלַד בּוֹ וְהִשְׁחִירוּ שְׁתֵּיהֶן אוֹ אַחַת מֵהֶן. הִקְצִירוּ שְׁתֵּיהֶן אוֹ אַחַת מֵהֶן. נִסְמַךְ הַשְּׁחִין לִשְׁתֵּיהֶן אוֹ לְאַחַת מֵהֶן. הִקִּיף הַשְּׁחִין אֶת שְׁתֵּיהֶן אוֹ אַחַת מֵהֶן. אוֹ שֶׁחִלְּקָן הַשְּׁחִין וּמִחְיַת הַשְּׁחִין וְהַמִּכְוָה וּמִחְיַת הַמִּכְוָה וְהַבֹּהַק. הֲרֵי זֶה טָהוֹר. נוֹלַד לוֹ שֵׂעָר לָבָן אַחֵר אוֹ מִחְיָה הֲרֵי זֶה טָמֵא מִפְּנֵי שֶׁבָּא כֻּלּוֹ לָבָן בַּתְּחִלָּה. אֶחָד שֶׁפָּרְחָה הַצָּרַעַת בְּכֻלּוֹ כְּאַחַת וְאֶחָד שֶׁפָּשְׂתָה וּפָרְחָה מְעַט מְעַט עַד שֶׁהִלְבִּין כֻּלּוֹ. אִם מִתּוֹךְ הֶסְגֵּר אוֹ מִתּוֹךְ הֶחְלֵט טָהוֹר. וְאִם אַחַר הַפִּטּוּר טָמֵא. וְאִם בַּתְּחִלָּה יַסְגִּיר. אֶחָד שֶׁהָיָה כֻּלּוֹ מַרְאֶה אֶחָד אוֹ שֶׁהָיָה כֻּלּוֹ לָבָן בְּאַרְבַּע הַמַּרְאוֹת שֶׁבַּלֹּבֶן וּבְאַרְבַּע שֶׁל פָּתוּךְ הַכּל מִצְטָרְפִין בֵּין לְטַהֲרוֹ בֵּין לְטַמְּאוֹ כְּמוֹ שֶׁבֵּאַרְנוּ:
כסף משנה
2.
The following rules apply when a person comes initially while he is entirely white with tzara'at. If he has a patch of healthy skin or two white hairs, he is deemed definitively impure. If there is no sign of impurity, he is isolated for one week. If white hair or a patch of healthy skin emerges, he is deemed definitively impure. If no sign emerges, he is isolated for a second week. If no sign emerges, he is deemed pure, for the laws applying to this large baheret are the same as those governing a small one.
If he was deemed impure because of two white hairs that emerged and either both or one of them turned black, either both or one of them became short, a boil grew next to either of them or one of them or encompassed both of them or one of them, a boil, a healed boil, a burn, a healed burn, or a bohak divided one hair from the other, he is pure. If white hair or healthy flesh emerges, he is impure, because he came initially while entirely white.
Whether the tzara'at spread over the person's entire skin all at once or whether it spread little by little until he became entirely white, if this occurred while the person was isolated or while he was deemed definitively impure, he is pure. If it occurred after he was released from the inspection process, he is impure. And if it occurred at the outset, he should be isolated. Similarly, it is irrelevant whether the blemish is entirely of one shade or that it is entirely white, but has the four shades of white and the four shades of petuch intermingled. All of these shades can be combined and considered as a single blemish, whether to cause the person to be declared pure or to be declared impure, as we explained.

הלכה ג
הָיְתָה בּוֹ בַּהֶרֶת כִּגְרִיס וּבָהּ מִחְיָה כַּעֲדָשָׁה וְהֻחְלַט בְּמִחְיָה וּפָרְחָה הַצָּרַעַת בְּכֻלּוֹ וְאַחַר כָּךְ הָלְכָה הַמִּחְיָה. אוֹ שֶׁהָלְכָה הַמִּחְיָה תְּחִלָּה וְאַחַר כָּךְ פָּרְחָה בְּכֻלּוֹ. הֲרֵי זֶה טָהוֹר וַאֲפִלּוּ נוֹלַד לוֹ שֵׂעָר לָבָן. נוֹלְדָה בּוֹ מִחְיָה טָמֵא שֶׁנֶּאֱמַר (ויקרא יג יד) "וּבְיוֹם הֵרָאוֹת בּוֹ בָּשָׂר חַי יִטְמָא". וְהוּא שֶׁתִּהְיֶה כַּעֲדָשָׁה מְרֻבַּעַת אוֹ יֶתֶר. הָיְתָה בּוֹ בַּהֶרֶת וּבָהּ שֵׂעָר לָבָן וְהֻחְלַט בְּשֵׂעָר לָבָן וְאַחַר כָּךְ פָּרְחָה בְּכֻלּוֹ אַף עַל פִּי שֶׁשֵּׂעָר לָבָן בִּמְקוֹמוֹ עוֹמֵד טָהוֹר. שֶׁנֶּאֱמַר וּבְיוֹם הֵרָאוֹת בּוֹ בָּשָׂר חַי יִטְמָא בְּמִחְיָה מִתְטַמֵּא זֶה שֶׁנֶּהְפַּךְ כֻּלּוֹ לָבָן אַחַר הֶחְלֵט אוֹ אַחַר הֶסְגֵּר. וְאֵינוֹ מִטַּמֵּא בְּשֵׂעָר לָבָן. הֶחְלִיטוֹ בְּפִשְׂיוֹן וְאַחַר כָּךְ פָּשְׂתָה וּפָרְחָה בְּכֻלּוֹ טָהוֹר. וְאִם נִרְאֵית בּוֹ מִחְיָה טָמֵא:
כסף משנה
3.
The following rules apply when a person had a baheret the size of a gris in which there was a patch of healthy flesh the size of a lentil and he was deemed definitively impure because of the healthy flesh. Afterwards, the tzara'at spread over his entire body and the healthy flesh disappeared. Alternatively, the healthy flesh disappeared and then the tzara'at spread over his entire body. He is considered as pure. This applies even if white hair emerges. If, however, healthy skin emerges, he is impure, as Leviticus 12:14 states: "On the day he exhibits healthy flesh, he will be deemed impure," provided the healthy flesh is the size of a square superimposed on a lentil or larger.
Different rules apply if one had a baheret with white hair and he was deemed impure because of it and afterwards, the tzara'at spread over his entire body. Even though the white hair remains in place, he is pure, as can be derived from the verse: "On the day he exhibits healthy flesh, he will be deemed impure." Implied is that a person whose entire skin turned white after being deemed definitively impure or being isolated becomes impure because of healthy flesh, but not because of white hair. If he was deemed impure because his blemish spread and then it continued to spread and covered his entire body, he is pure. If he exhibits any healthy flesh, he is impure.

הלכה ד
אַף רָאשֵׁי אֵיבָרִים שֶׁאֵינָן מִטַּמְּאִין מִשּׁוּם מִחְיָה שֶׁבְּתוֹךְ הַבַּהֶרֶת מִטַּמְּאִין וּמְעַכְּבִין אֶת הַנֶּהְפָּךְ כֻּלּוֹ לָבָן. כֵּיצַד. מֻחְלָט אוֹ מֻסְגָּר שֶׁהִלְבִּין כֻּלּוֹ בְּצָרַעַת חוּץ מִכַּעֲדָשָׁה בָּשָׂר חַי אֲפִלּוּ בְּרֹאשׁ אֶצְבָּעוֹ אוֹ בְּרֹאשׁ חָטְמוֹ וְכַיּוֹצֵא בָּהֶן הֲרֵי הוּא בְּטֻמְאָתוֹ. וְכֵן זֶה שֶׁנֶּהְפַּךְ כֻּלּוֹ לָבָן וְטָהַר אִם חָזַר בּוֹ כַּעֲדָשָׁה בָּשָׂר חַי אֲפִלּוּ בְּרֹאשׁ אֶחָד מִן הָאֵיבָרִים הֲרֵי זֶה מֻחְלָט. נֶהְפַּךְ כֻּלּוֹ לְמַרְאֵה צָרַעַת חוּץ מִכַּעֲדָשָׁה אֲפִלּוּ בְּרֹאשׁ אֶחָד מִן הָאֵיבָרִים שֶׁנֶּהְפַּךְ לְבֹהַק הֲרֵי זֶה טָמֵא מֻחְלָט שֶׁנֶּאֱמַר (ויקרא יג יג) "וְהִנֵּה כִסְּתָה הַצָּרַעַת", לֹא הַבֹּהַק. אֲפִלּוּ הָיְתָה מִקְצָת הָעֲדָשָׁה בָּשָׂר חַי וּמִקְצָתָהּ בֹּהַק הֲרֵי זוֹ סִימַן טֻמְאָה. נֶהְפַּךְ כֻּלּוֹ לְמַרְאֵה צָרַעַת וְטִהַר וְאַחַר כָּךְ חָזַר בּוֹ בָּשָׂר כְּמַרְאֵה הַבֹּהַק הֲרֵי זֶה טָהוֹר עַד שֶׁיֵּרָאֶה בּוֹ כַּעֲדָשָׁה בָּשָׂר חַי שֶׁנֶּאֱמַר (ויקרא יג יד) "וּבְיוֹם הֵרָאוֹת בּוֹ בָּשָׂר חַי", לֹא בֹּהַק. חָזַר בּוֹ כַּעֲדָשָׁה מִקְצָתָהּ בָּשָׂר חַי וּמִקְצָתָהּ בֹּהַק אֵינוֹ סִימַן טֻמְאָה וַהֲרֵי הוּא בְּטָהֳרָתוֹ:
כסף משנה
4.
Even the tips of limbs that do not impart impurity as healthy flesh when they are located in the midst of a baheret, do impart impurity and prevent a person from being deemed pure if his entire flesh turns white.
What is implied? If a person who was definitively deemed impure or who was isolated whose entire flesh turned white because of tzara'at with the exception of a lentil's size of healthy flesh, even if the healthy flesh is located on his fingertip, the tip of his nose, or the like, he remains impure.
Similarly, if a person's entire flesh turned white and he was declared pure and then a lentil's size of healthy flesh returned, even at the tips of one of his limbs, he should be definitively deemed impure. If his flesh turned entirely to a shade of tzara'at except for a lentil's size portion - even on the tips of his limbs that turned to a bohak, he should be deemed definitively impure, as can be derived from Leviticus 13:12: "If... the tzara'at will cover the entire skin...." Implied is that it must be covered by tzara'at, not a bohak. Even if part of the lentil's size portion was healthy flesh and part was a bohak, it is a sign of impurity.
If a person's entire flesh turned to one of the shades of tzara'at and he was declared pure and then a portion of his flesh turned to the color of a bohak, he remains pure until he exhibits a lentil's size of healthy flesh, as implied by the verse: "On the day he exhibits healthy flesh...." Implied is that he must exhibit healthy flesh, not a bohak. If a lentil's size portion of flesh [changed appearance, part was healthy flesh and part was a bohak, it is not considered a sign of impurity and the person is still considered as pure.

הלכה ה
כָּל טָמֵא שֶׁפָּרְחָה הַצָּרַעַת בְּכֻלּוֹ טָהוֹר. נִתְגַּלָּה מִמֶּנּוּ כַּעֲדָשָׁה בָּשָׂר חַי נִטְמָא. חָזַר וְנִתְכַּסָּה בְּצָרַעַת טָהוֹר. חָזַר וְנִתְגַּלָּה נִטְמָא אֲפִלּוּ מֵאָה פְּעָמִים. הִתְחִיל הַבָּשָׂר הַחַי לְהִתְגַּלּוֹת וַהֲרֵי הוּא מוֹסִיף וְהוֹלֵךְ וְהַצָּרַעַת מִתְמַעֶטֶת הֲרֵי זֶה בְּטֻמְאָתוֹ עַד שֶׁתִּתְמַעֵט הַבַּהֶרֶת מִכִּגְרִיס:
כסף משנה
5.
Whenever tzara'at spreads over the entire body of an impure person, he becomes pure. If a lentil's size portion of healthy flesh was revealed, he is impure. If his entire flesh was again covered with tzara'at, he is pure, If healthy flesh was again revealed, he is impure. These rulings are given even if the cycle repeats itself 100 times.
If healthy flesh began to be revealed and it continues to grow and the size of the tzara'at shrinks, the person remains impure until the baheret becomes smaller than a gris.

הלכה ו
כָּל הָרָאוּי לִטַּמֵּא בְּנֶגַע הַבַּהֶרֶת מְעַכֵּב הַהוֹפֵךְ כֻּלּוֹ לָבָן וְכָל שֶׁאֵינוֹ רָאוּי לִטַּמֵּא בְּנֶגַע הַבַּהֶרֶת אֵינוֹ מְעַכֵּב. כֵּיצַד. פָּרְחָה בְּכֻלּוֹ אֲבָל לֹא בָּרֹאשׁ וּבַזָּקָן בַּשְּׁחִין וּבַמִּכְוָה הַמּוֹרְדִין. אוֹ שֶׁנִּשְׁאַר פָּחוֹת מִכַּעֲדָשָׁה בָּשָׂר חַי סָמוּךְ לַשְּׁחִין וְלַמִּכְוָה הַמּוֹרְדִין וְלָרֹאשׁ וְלַזָּקָן הֲרֵי זֶה טָהוֹר. חָזַר הָרֹאשׁ וְהַזָּקָן וְנִקְרְחוּ וְכֵן אִם חָיוּ הַשְּׁחִין וְהַמִּכְוָה וְהֶעֱלוּ צָרֶבֶת הֲרֵי זֶה טָמֵא עַד שֶׁתִּפְרַח הַצָּרַעַת בָּהֶן שֶׁהֲרֵי הֵן רְאוּיִין לְבַהֶרֶת. הָיוּ בָּהּ שְׁתֵּי בֶּהָרוֹת אַחַת יֵשׁ בָּהּ סִימַן טֻמְאָה וְאַחַת טְהוֹרָה וּפָרְחָה הַטְּהוֹרָה לַטְּמֵאָה וְאַחַר כָּךְ פָּרְחָה בְּכֻלּוֹ הֲרֵי זֶה טָהוֹר מִפְּנֵי שֶׁהָיָה מֻחְלָט בְּטֻמְאָה אַף עַל פִּי שֶׁהַטְּהוֹרָה הִיא שֶׁפָּרְחָה. וְלֹא עוֹד אֶלָּא אֲפִלּוּ הָיוּ אַחַת בִּשְׂפָתוֹ הָעֶלְיוֹנָה וְאַחַת בִּשְׂפָתוֹ הַתַּחְתּוֹנָה אוֹ בִּשְׁתֵּי אֶצְבְּעוֹתָיו אוֹ בִּשְׁנֵי רִיסֵי עֵינָיו וּכְשֶׁהֵן נִדְבָּקִין זֶה לָזֶה נִרְאִין שְׁתֵּי הַבֶּהָרוֹת כְּבַהֶרֶת אַחַת הוֹאִיל וּפָרְחָה בְּכֻלּוֹ טָהוֹר:
כסף משנה
6.
Any portion of skin that is fit to contract impurity because of baheret but remains healthy prevents a person whose entire flesh is becoming white from being placed in that category. Any portion of skin that is not fit to contract impurity because of baheret does not prevent a person whose entire flesh is becoming white from being placed in that category although that portion of skin remains healthy.
What is implied? When tzara'at spreads over a person's entire skin, but not on his head or his chin, nor onto a festering boil or burn or there is less than a lentil's size portion of healthy flesh next to a festering boil or burn or to his head or chin, he is pure. If the hair fell from the head and the chin or if a scab formed over the boil or the burn, the person is impure until the tzara'at spreads to them, for they are fit to contract impurity because of a baheret.
If there were two beharot, one had a sign of impurity and one was pure, the pure one spread to the impure and then covered the person's skin entirely, he is deemed pure. The rationale is that he was previously deemed definitively impure, even though it was the pure one that spread. Furthermore, this ruling applies even if one of the beharot was on his upper lip and the other on his lower lip or on two of his fingers or on his two eyelids, and thus when they are closed together, the two beharot appear as one. Nevertheless, since tzara'at spread over the person's entire skin, he is pure.

הלכה ז
יֵשׁ מַרְאֶה נִגְעוֹ לְכֹהֵן וְנִשְׂכַּר מִפְּנֵי שֶׁהִקְדִּים לְהַרְאוֹתוֹ וְלֹא נִתְאַחֵר. וְיֵשׁ מַרְאֶה וּמַפְסִיד. כֵּיצַד. מִי שֶׁהָיָה מֻחְלָט וְהָלְכוּ לָהֶן סִימָנֵי טֻמְאָה וְלֹא הִסְפִּיק לְהַרְאוֹתוֹ לַכֹּהֵן עַד שֶׁפָּרְחָה בְּכֻלּוֹ טָהוֹר. וְאִלּוּ קָדַם וְהֶרְאָה לַכֹּהֵן וּפְטָרוֹ קֹדֶם שֶׁיַּהֲפֹךְ וְנֶהְפַּךְ אַחַר הַפִּטּוּר הָיָה מֻחְלָט כְּמוֹ שֶׁבֵּאַרְנוּ. הָיְתָה בּוֹ בַּהֶרֶת וְאֵין בָּהּ כְּלוּם וְלֹא הִסְפִּיק לְהַרְאוֹתוֹ לַכֹּהֵן עַד שֶׁפָּרְחָה בְּכֻלּוֹ הֲרֵי זֶה טָמֵא וְצָרִיךְ הֶסְגֵּר. וְאִלּוּ קָדַם וְהֶרְאָה לַכֹּהֵן וְהִסְגִּירוֹ קֹדֶם שֶׁיַּהֲפֹךְ וְנֶהְפַּךְ מִתּוֹךְ הֶסְגֵּר הָיָה טָהוֹר כְּמוֹ שֶׁבֵּאַרְנוּ:
כסף משנה
7.
There are those who show their blemishes to a priest and benefit from doing so, because they showed it to him early and did not delay, and others who suffer from doing so.
What is implied? A person was definitively deemed impure. His signs of impurity disappeared, but he did not have the opportunity to show this development to a priest before the tzara'at spread over his entire body. He is pure. If, however, he had acted earlier and showed it to the priest previously, he would have been released from the inspection process before it spread over his entire body. Thus it would have spread after he was released, in which instance, he would be deemed definitively impure, as we explained.
If he had a baheret without any signs of impurity and he did not have the opportunity to show it to a priest before it spread over his entire body, he is impure and must be isolated. If, however, he had acted earlier and had shown it to the priest, he would have been isolated before it spread. Thus it would have spread after he was isolated, in which instance, he would be pure, as we explained.

טהרה הלכות טומאת צרעת פרק ז
Taharah Tumas Tzara’as Chapter 7