to have impetigo, ringworm, mange, scabies, or some kind of itch, a cutaneous disease (see Molina)
Alonso de Molina:
xixioti. ni. (pret. onixixiot.) tener empeynes, o sarna. Alonso de Molina, Vocabulario en lengua castellana y mexicana y mexicana y castellana, 1571, part 2, Nahuatl to Spanish, f. 160r. col. 1. Thanks to Joe Campbell for providing the transcription.