asboe-hansen sign asboe-hansen sign the asboe-hansen sign (also known as "indirect nikolsky sign'" or "nikolsky ii sign") refers to the extension of a blister to adjacent unblistered skin when pressure is put on the top of the bulla. this sign is named for the danish physician gustav asboe-hansen (1917–1989). it is considered an indirect diagnostic tool in toxic epidermal necrolysis (ten).