Paronychia is an infection of the fold of skin surrounding a nail (the nail fold). It may develop suddenly (acute paronychia) due to a bacterial infection, or gradually (chronic paronychia), usually due to a yeast infection.
Acute paronychia causes pain and swelling on the side of the nail fold and a build-up of pus around the nail. Chronic paronychia causes similar symptoms but does not usually produce a build-up of pus.
Treatment is with antibiotics or antifungal medications. With acute paronychia, it may also be necessary to drain a build-up of pus