scurvy (n.)youdaoicibaDictYouDict
1560s, noun use of adjective scurvy "covered with scabs, diseased, scorbutic" (early 15c.), variant of scurfy. It took on the narrower meaning of Dutch scheurbuik, French scorbut "scurvy," in reference to the disease characterized by swollen and bleeding gums, prostration, etc., perhaps from Old Norse skyrbjugr, which is perhaps literally "a swelling (bjugr) from drinking sour milk (skyr) on long sea voyages;" but OED has alternative etymology of Middle Dutch or Middle Low German origin, as "disease that lacerates the belly," from schoren "to lacerate" + Middle Low German buk, Dutch buik "belly."
psorayoudaoicibaDictYouDict
"Any of various skin diseases characterized by the presence of scabs or scales, usually with itching; especially scabies, mange, or (in later use) psoriasis", Late 16th cent.; earliest use found in John Banister (1532/3–?1610), surgeon. From classical Latin psōra or its etymon ancient Greek ψώρα itch, mange from an alternative form (with different vocalism) of the stem of ψῆν to rub, wipe + -ρα, suffix forming nouns.
rupiayoudaoicibaDictYouDict
"A skin disease in which there is an eruption of vesicles or pustules which develop into ulcerated sores covered by thick, dark scabs or crusts; especially a form of secondary syphilis characterized by such lesions", Early 19th cent.; earliest use found in Thomas Bateman (1778–1821), physician and dermatologist. From scientific Latin rupia from ancient Greek ῥύπος dirt, filth + classical Latin -ia.