Garav and Chazazit the Egyptian Itch in Rabbinic Law

Our Rabbis taught: these are the ones for which one may not slaughter [as a sacrifice], neither in the Temple nor in the country: a beast afflicted with garav [a scab] or chazazit [lichen-rash]. But is garav disqualified - is not garav written in the Torah [as a curse, implying it is curable]? And is chazazit disqualified - is not chazazit written in the Torah? As it was taught: "garav" - this is the dry scab; "yalefet" - this is the Egyptian chazazit; for Resh Lakish said, why is it called yalefet? Because it clings and goes on clinging until the day of death. Now, the difficulty of chazazit against chazazit is no difficulty: here it speaks of the Egyptian chazazit [incurable], there of ordinary chazazit. But garav against garav is a difficulty. That too is no difficulty: this one is moist, that one is dry; the moist can be healed, the dry cannot. But is it not written, "The LORD will strike you with the boil of Egypt and with garav and with the scab" (Deuteronomy 28:27)? Since it writes "and with the scab," this garav is the moist kind, and yet it says, "of which you cannot be healed" (Deuteronomy 28:27). Rather, there are three types: the one of Scripture's curse is dry both within and without; [the one of the Mishnah is moist within and without]; and the Egyptian one was moist without and dry within - as Rabbi Joshua ben Levi said: the boil that the Holy One, blessed be He, brought, and so on.