Lévitique 13:52

FOR IT IS A LEPROSY THAT IS ‘MAM’ERETH’ (FRETTING). “Mam’ereth is an expression of ‘silon mam’ir’ (a pricking brier). The Midrashic interpretation is: attach a me’eirah (curse) to it — so that you will have no benefit from it.” This is Rashi’s language. And Onkelos translated: “a leprosy that is mechasra (pricking).” This interpretation he also derived from ‘silon mam’ir’ (a pricking brier), for in Aramaic any shrub which causes a pricking pain is called chisra. Thus: “k’chizra (as a thorn) in a ball of wool;” “take thy good-natured advice and throw it over achizri (the hedge).” And the truth of the matter is that mam’ereth is indeed an expression of curse, that it is to say, it is G-d’s curse upon the garment and house, as I have mentioned. But the Midrash which states that it is forbidden to derive any benefit from it [a leprous garment] is based [not on the word mam’ereth as Rashi had it, but] on the redundancy of expression. appears in Verses 51 and 52 in the same connection. Since one is redundant, it serves as the basis for the Midrashic interpretation mentioned. The same law applies to a leprous house, and it is derived from the verse, And he shall break down the house.
Thus also I have found in the Talmud Yerushalmi of Tractate Orlah: “If stones were removed from a house affected with leprosy and made into plaster, some Rabbis taught that they become free of their impurity, and some taught that they do not become free of their impurity. Those who said that they become free, are also of the opinion that they may now be used [for some benefit], and those who say that they do not become free are also of the opinion that they are still forbidden [to be made use of], for it is written: it is a leprosy that is ‘mam’ereth’, meaning, attach a curse to it and derive no benefit from it. Rabbi Abohu said in the name of Rabbi Yochanan: All things which must be burnt, one may derive benefit from their ashes, except for the ashes of an idol. Rabbi Chiya the son of Yosei asked Rabbi Yochanan: ‘There is the case of the ashes of a house [affected with leprosy], which is not related to idolatry, and yet you say that the ashes thereof are forbidden for any use [like the stones which have been turned into lime or plaster]! Said Rabbi Yochanan to him: ‘This is different,’ since [concerning a house affected with leprosy] it is written that it be ‘broken down.’” (Deuteronomy 12:3), we derive from a similarity of phrases the law that just as it is forbidden to have any benefit from idols, so we are under the same stricture of making any use from the stones of a house which had been affected with leprosy (P’nei Moshe, ibid.).
Metzora

צרעת ממארת, similar to Ezekiel 28,24 סילון ממאיר וקרץ מכאיב, “prickling briers and lacerating painful thorns.” We also have a similar phenomenon described in Deuteronomy 28,20 המארה והמהומה, “curse and confusion.”

צרעת ממארת היא, “it is a malignant skin disease;” the afflicted person, when he feels burning of the skin will feel tempted to peel off the affected part of the skin, and as a result it would come back on an even bigger area of his skin.