Inflamed skin tumors.
And the LORD said unto Moses and unto Aaron, Take to you handfuls of ashes of the furnace, and let Moses sprinkle it toward the heaven in the sight of Pharaoh. 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. ( Exodus 9:8-9 )
Bibliography Information"Entry for 'Blains'". A King James Dictionary.