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Toenail ridges

At the recommendation of his physician during a telehealth visit 9 months earlier, a 25-year-old man presented to the Family Medicine Skin Care Clinic for evaluation of ridges on his toenails. He did not recall any injuries or severe illness over the previous year but mentioned that he had been under stress due to the COVID-19 pandemic. Examination revealed transverse ridges on both great toenails with lesser changes on the other toenails.

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Toenail ridges

Transverse ridges that grow out with the nails are called Beau lines, also known as Beau’s ridges. This contrasts with Mees lines which are transverse white bands that grow out with the toenails, are nonpalpable, and are attributed to arsenic poisoning.

Beau lines are caused by a disruption in nail growth that can result from trauma, hypotension, or systemic or severe illness; they have also been reported in cases of COVID-19.1 Beau lines can occur on a single nail if the trauma or injury is isolated to 1 digit. If there was a systemic illness or stress, the lines can affect all 20 nails. The time of the inciting event can be approximated by how far the lines are from the cuticle. While there is some variability, it usually takes 12 to 18 months to grow an entirely new toenail. If the Beau lines have grown halfway out, then the stressor likely occurred 6 to 9 months earlier.

In this image, some asymmetry is visible between the right and left great toenails and there are some subtle distal changes, raising the possibility that there was more than 1 injury to this patient’s system (or prolonged difficulty). The patient said that to his knowledge, he had not been infected with COVID-19. However, hair and nail changes may be the only finding in some individuals who have been infected with COVID-19.1

This patient was counseled regarding the nature of this disorder and that without knowing what illness or injury caused the change, it was a benign finding. He was advised that it did not appear to be onychomycosis and did not require any medications or antifungal therapy. The patient was told to follow up if any changes developed.

Image courtesy of Daniel Stulberg, MD. Text courtesy of Daniel Stulberg, MD, FAAFP, Department of Family and Community Medicine, University of New Mexico School of Medicine, Albuquerque.

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