paronychia; whitlow
Medical term for inflammation of the skin around a fingernail or toenail. 'Whitlow' and 'felon' are older or less common English synonyms; 'agnail' is rare.
Paronychia is a condition where the skin around the nail becomes red and swollen.
It is said that diabetic patients are prone to paronychia.
Compound of 爪 (sō, 'nail') + 周囲 (shūi, 'surrounding area') + 炎 (en, 'inflammation').