Where does “pityriasis” come from?

pityriasis (New Latin) comes from Koine Greek πιτυρίασις, from Ancient Greek πίτῡρον.

Ancestry of “pityriasis”, step by step

Step	Language	Word	Meaning
1	Koine Greek	πιτυρίασις	—
2	Ancient Greek	πίτῡρον	—

pityriasis — Etymology, Origin & Word History | Etymology Explorer