Anatomical changes in retronychia and onychomadesis detected using ultrasound.

The nail, a fast-growing organ, is sensitive to changes in the germinal matrix, and, as would be expected, a severe systemic illness can affect the growth rate of the ungual matrix, which occasionally results in temporary growth arrest (Beau’s line). Thus, recovery from growth arrest can be associated with onychomadesis, also called nail shedding, a condition that indicates the separation of the nail plate from the nail matrix area, after a (4to 8-week) period of latency after systemic insult. The length in the long axis of the furrow represents the exact duration of the disease that has affected the matrix. The keratinized nail bed alone fills the gap between the old and new nail plate. In the case of onychomadesis, its manifestations are transient and resolve within several months.