|Easton's Bible Dictionary|
Occurs only in connection with the sixth plague of Egypt (Exodus 9:9, 10). In Deuteronomy 28:27, 35, it is called "the botch of Egypt." It seems to have been the fearful disease of black leprosy, a kind of elephantiasis, producing burning ulcers.
Int. Standard Bible Encyclopedia
blanz (abha`bu`ah: only in Exodus 9:9, 10): Pustules containing fluid around a boil or inflamed sore. It is an Old English word "bleyen," used sometimes as a synonym for boil. Wyclif (1382) uses the expression "stinkende bleyne" for Job's sores. The Hebrew word is from a root which means that which bubbles up.
Blains (2 Occurrences)
Exodus 9:9 And it shall become small dust in all the land of Egypt, and shall be a boil breaking forth with blains upon man, and upon beast, throughout all the land of Egypt. (KJV JPS ASV WBS YLT)
Exodus 9:10 And they took ashes of the furnace, and stood before Pharaoh; and Moses sprinkled it up toward heaven; and it became a boil breaking forth with blains upon man, and upon beast. (KJV JPS ASV WBS YLT)