Fromskin +‎worm, in later use partly afterGermanHautwurm.

skinworm (pluralskin worms)

1. A smallworm or otherparasite which infects theskin.
   • 1603,Michel de Montaigne, chapter 12, inJohn Florio, transl.,The Essayes […], book II, London:[…]Val[entine] Simmes forEdward Blount […],→OCLC:

     Alike desires perturbe both askinne-worme[translatingciron], and an Elephant.

• wormskin