Retronychia By Chris G Adigun, MD, Dermatology & Laser Center of Chapel Hill Reviewed / Revised Dec 2021 View Patient Education Treatment Topic Resources Acute Retronychia Acute Retronychia (Big Toe) Chronic Retronychia Chronic Retronychia (Big Toes) Retronychia is a less common form of paronychia, which is infection of the periungual tissues.