A condition affecting the area surrounding or above the fingernail or toenail, particularly nail bed inflammation or skin overgrowth.
From epi- (Greek 'upon') + onychia (from onyx 'nail' + -ia, a noun suffix). An anatomical term for pathological conditions of the nail region.
Your fingernails are surrounded by several different anatomical regions, and doctors needed specific names for each one—epionychia refers to problems 'upon the nail'! It's the kind of specificity that makes medical terminology seem like a secret language.
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