dandruff: [16] The word dandruff (or dandriff, as it commonly used to be) first appears, out of the blue, in the mid 16th century, with no known relatives. Its first element, dand-, remains utterly obscure, but the second part may have been borrowed from Old Norse hrufa or Middle Low German rōve, both meaning ‘scab’ (Middle English had a word roufe ‘scab, scurf’, and modern Dutch has roof).
1540s, first element obscure, second element is Northumbrian or East Anglian dialectal huff, hurf "scab," from Old Norse hrufa, from Proto-Germanic *hreufaz, source of Old English hreofla "leper."
