Leprosy is the word the translators chose to use in place of the Hebrew word Sara'at.
The definition of leprosy is-
Leprosy, also known as Hansen's disease, is a chronic infectious disease caused by Mycobacterium leprae. The disease mainly affects the skin, the peripheral nerves, mucosal surfaces of the upper respiratory tract and the eyes. Leprosy is known to occur at all ages ranging from early infancy to very old age.
The definition of Sara'at-
Leviticus 13:2 says, "The Hebrew word sara'at was used for various diseases affecting the skin, not necessarily leprosy. ... The Hebrew word in question is sara'at. In Arabic the root meaning is stricken, smitten of God." Sara'at is a ritualistic term, denoting defilement or uncleanness.
The leprosy or Sara'at of Naaman in which Gehazi was cursed accompanied a sign or a mark of the whitening of the skin, showing Gehazi had been stricken with this condition which more or less showed Naaman had been cursed, but not necessarily that he'd have boils and ulcers, respiratory tract infections as a typical leper would have.
The leprosy of Naaman only seemed to be skin deep, and there is nothing written to imply otherwise.
2 Kings 5-13-14
13 And his servants came near, and spake unto him, and said, My father, if the prophet had bid thee do some great thing, wouldest thou not have done it? how much rather then, when he saith to thee, Wash and be clean?
14 Then went he down, and dipped himself seven times in Jordan, according to the saying of the man of God: and his flesh came again like unto the flesh of a little child, and he was clean.
Notice in the above verses, Naaman only had to wash himself, and his skin became like that of a little child. His flesh, not his organs or respiratory system. He didn't have to grow any new limbs or any such thing. The sign of him being smitten, stricken, or cursed, was his skin becoming white as snow. The sign of his being healed was that his flesh became like the flesh of a little child, not the flesh of a newborn, but the flesh of a little child. Little children tend to have a healthy glow about their skin which has by the time they are past infancy, has gained its color and radiance.
Also not the case of Miriam
9And the anger of the LORD was kindled against them; and he departed. 10And the cloud departed from off the tabernacle; and, behold, Miriam became leprous, white as snow: and Aaron looked upon Miriam, and, behold, she was leprous. 11And Aaron said unto Moses, Alas, my lord, I beseech thee, lay not the sin upon us, wherein we have done foolishly, and wherein we have sinned. 12Let her not be as one dead, of whom the flesh is half consumed when he cometh out of his mother's womb.
Again, Miriam didn't have to grow any new limbs or have a healing of boils, or respiratory infection. The sign of Miriam's healing would be when her skin color was restored to its former state instead of the snow-white condition caused by the curse G-d had placed upon her. The curse in which Miriam's skin became like an infant who is half consumed by his mother's womb being still white and under-developed.
Another example of a sign of sara'at is Moses placing his hand in his and bosom and it turning leprose/sara'at, or white as snow.
And the Lord said furthermore unto him, “Put now thine hand into thy bosom.” And he put his hand into his bosom; and when he took it out, behold, his hand was leprous as snow.
Notice once again, a sign of Moses having leprosy or Sara'at, was simply his skin becoming white. Nowhere does the verses state he had any of the conditions usually accompanied with the type of leprosy we know of today, nor not even the same type of leprosy found in Leviticus which is accompanied by a scab or bright spot
When a man shall have in the skin of his flesh a rising, a scab, or bright spot, and it be in the skin of his flesh like the plague of leprosy; then he shall be brought unto Aaron the priest, or unto one of his sons the priests:
Not one place in the bible does it ever mention anyone being cursed, afflicted, stricken, smitten, with melanin as some heretics previously taught. Truth be told, melanin would have been and still is a blessing to the people living in "Africa" and the so-called middle east today, it is the color of the human creation from the beginning, which he formed in His image and in His likeness, nothing lacking. Without melanin, the rate of skin cancer for that climate would have increased as it has today amongst some of its non-melanated population today.
Humans with light skin pigmentation have skin with low amounts of eumelanin, and possess fewer melanosomes than humans with dark skin pigmentation. Light skin provides better absorption qualities of ultraviolet radiation. This helps the body to synthesize higher amounts of vitamin D for bodily processes such as calcium development. Light-skinned people who live near the equator with high sunlight are at an increased risk of folate depletion. As a consequence of folate depletion, they are at a higher risk of DNA damage, birth defects, and numerous types of cancers, especially skin cancer.
The distribution of light-skinned populations is highly correlated with the low ultraviolet radiation levels of the regions inhabited by them. Historically, light-skinned populations almost exclusively lived far from the equator, in high latitude areas with low sunlight intensity; for example, in Northwestern Europe. Due to colonization, imperialism, and increased mobility of people between geographical regions in recent centuries, light-skinned populations today are found all over the world