Retronychia: A Case Report Including Ultrasound Imaging and Surgical Treatment.

Retronychia is a recently described disorder caused by ingrowth of the proximal nail plate into the proximal nail fold. This situation provokes chronic paronychia refractory to antimicrobial therapy. Ultrasound has been proposed as the noninvasive method of choice to confirm the diagnosis and rule out other differential diagnoses, particularly local tumors and arthritic disease. The presence of 2 or more overlapping nail plates and a reduced distance between the root of the nail plate and the base of the distal phalanx could be the ultrasound hallmarks of this condition. Nail plate avulsion is the treatment of choice and is curative. Knowledge of retronychia is still limited among dermatologists, which can lead to diagnostic and therapeutic errors and delay. This has prompted us to present this new case.