Easton's Bible Dictionary (1897)
Occurs only in connection with the sixth plague of Egypt (Ex. 9:9, 10). ” It seems to have been the fearful disease of black leprosy, a kind of elephantiasis, producing burning ulcers.
Smith's Bible Dictionary (1863)
” It seems to have been the black leprosy, a fearful kind of elephantiasis.
Hastings' Dictionary of the Bible (1898) & Schaff's Bible Dictionary
BLAINS . Ex 9:9. Burning pustules or ulcers, which broke out upon the Egyptians and all their beasts, and constituted the sixth plague. " — Smith. Perhaps reference is made to this plague in Deut 28:27.