Sonography of the Nail

Ultrasonographic Criteria for Diagnosing Unilateral and Bilateral Retronychia

“…In addition, in nail psoriasis, there are other concomitant US signs, such as hypoechogenicity and increased thickness of the nail bed, loss of definition of the ventral plate, hyperechoic deposits in the ventral plate, loss of definition of both plates, and wavy and thickened plates. All of these signs differ greatly from the US findings for retronychia . However, a psoriatic nail can develop retronychia, particularly in late or severe stages; therefore, we must be aware to recognize these entities on US.…”

“…The US equipment was a LOGIQ E9 XD Clear system with high, linear, and compact linear variable‐frequency transducers working in an upper range between 15 and 18 MHz (GE Healthcare, Waukesha, WI). The same settings were used in all cases and followed the recommendations of guidelines for performing dermatologic US studies and the reported techniques for examining the nail on US, which included grayscale and color Doppler evaluations in at least 2 perpendicular axes …”

“…Retronychia is a nail disorder characterized by embedding of the proximal nail plate into the proximal nail fold, which clinically appears as an apparent halt to nail growth with a chronic proximal paronychia . It may be an underestimated condition that can appear after or concomitant to a severe illness, can be related to stress‐relevant situations, can be secondary to trauma, including sports injuries, or can appear as an idiopathic episode . Additionally, it has been reported that retronychia may have a similar etiology as Beau lines and onychomadesis.…”

“…Moreover, this condition is usually unresponsive to only antibiotics, and commonly, management is surgical (onysectomy: ie, proximal avulsion of the nail) . Retronychia can appear in association with onychomadesis (ie, fragmentation of the nail plate), and since its original description in 1999, there have been an increasing number of case reports …”

“…Ultrasonography (US) has been shown to be useful for supporting the diagnosis of this condition . For example, a decreased distance between the origin of the nail plate and the base of the distal phalanx in comparison with the contralateral side has been reported in retronychia .…”