An Updated Overview on Retronychia

Abstract

Retronychia is an inflammatory process of the proximal nailfold caused by backward ingrowth of the nail plate. It appears to be secondary to proximal nail plate rupture caused primarily by wearing tight shoes, or related to a traumatic origin such as sports or dance. The proximal nail fold appears painful and inflamed in the acute form, whereas in the chronic state, the nail plate appears yellowish and thickened in addition to the inflammation. It primarily affects the great toe, sometimes bilaterally, and occasionally the fingers. It is sometimes accompanied by the development of granulation tissue near the proximal nail fold. A notably female predominance has been reported, especially in young or middle ages. Its diagnosis is based on the clinical triad: interruption of nail growth, proximal paronychia with elevation of proximal nail plate over the proximal nail fold, and xantonychia.

Nail avulsion is the treatment of choice and it is curative in most cases. However, mild cases may be initially treated with conservative therapies, including topical or intralesional steroids, chemical avulsion of the nail and clipping back the onycholytic nail plate.

Retronychia is a potentially underdiagnosed disease, with only a few reports in the English, French, Spanish, and Asian literature. This topic is updated in this review, which is illustrated with clinical and ultrasound images.