The discussion surrounding those suffering from Tzoraat focuses not on the actual illness but the mitzvot relating to becoming clean after having been rendered unclean as a result of the illness. Interestingly, the Torah itself doesn’t make a direct connection between the disease of Tzoraat and lashon hahrah or any other sin. There are however several Tanaitic texts that draw the connection between lashon harah and Tzoraat such as the Sifra on Sefer Vayikra. There is also a discussion in the Talmud (Eruchin 15a), which makes the connection although a bit tenuous. The Rambam, however makes a clear connection between the two, but treats it more within the framework of haggadah / musar rather than halachah.
Rabbi Israel Meir Hacohen from Radin, better known as the Chafetz Chaim was the first to actually connect the Tzoraat with lashon harah from a non haggadic and purely halachic position. The Chafetz Chaim recognized the extreme difficulty of human behavior in avoiding lashon harah but was determined to alter normative behavior by employing the use of halachah. It was his goal to create not only the awareness but also the practice of observing the halachot surrounding lashon harah as one would practice all the other 613 mitzvot. He was very clear that lashon harah wasn’t about musar but about halachah.
There were those who disagreed with the approach of the Chafetz Chaim and their argument centered on two points: Lashon harah, although important, can only be maintained through personal ethical conduct which is relative, by nature. This can’t be defined by halacha only by the will of the individual to distill in himself exemplary conduct and behavior. A second position was because observing this mitzvah demanded practically super human qualities that most of us are lacking, it was better to sin as a shogeg than as a mezid.
There is, of course, a more obvious problem with the construct of the Chafetz Chaim: If lashon harah is so connected to Tzorat then practically the entire Jewish community ought to be walking around with Tzorat. The convenient answer is that Tzorat was manifested only when there was a Temple, because then it was possible to be remedied through the good offices of the Priest. However, in a post exilic period, when there is no Temple and there are no “active” Priests, there can be no remedy; hence there is no true manifestation of the Tzorat. If this is the case than from a strictly halachic point of view we ought to be able to partake in lashon harah!