vitiligo vs disease of the skin

vitiligo and disease of the skin both are nouns.

Word	Noun	Adjective	Verb	Adverb
vitiligo	Yes	No	No	No
disease of the skin	Yes	No	No	No

As nouns, disease of the skin is a hypernym of vitiligo; that is, disease of the skin is a word with a broader meaning than vitiligo:

vitiligo: an acquired skin disease characterized by patches of unpigmented skin (often surrounded by a heavily pigmented border)
disease of the skin: a disease affecting the skin

Other hypernyms of vitiligo include skin disease, skin disorder.

vitiligo (noun)	disease of the skin (noun)
an acquired skin disease characterized by patches of unpigmented skin (often surrounded by a heavily pigmented border)	a disease affecting the skin