Akkadian

šullu - a pockmark or wart (CAD š 3, 241; AHw. 1266 )

Exact reconstruction of the sibilant is difficult since Akk. š does not correspond to Hbr. and Jud. s (note that the irregularities of PS sibilant reflexation in Akk. observed elsewhere are confined to the reverse situation: Akk. s instead of the expected š).Cf. šūlu ‘a partial or complete perforation’ [CAD š 2 451], [AHw 1237]. This word, found mostly in descriptions of internal organs, is once used to denote a feature of a newborn’s appearance and can be plausibly understood as a kind of skin eruption identical to šullu (šūlu), cf. discussion in [Holma 1912 22]. 

PS
*š/sVl(V)ˁ- - (kind of) disease causing scales on the skin; leprosy (SED I No. 243)