75-year-old man • recent history of hand-foot-mouth disease • discolored fingernails and toenails lifting from the proximal end • Dx?

Onychomadesis, sometimes considered a severe form of Beau’s line,^5,6 is defined by the spontaneous separation of the nail plate from the nail matrix. Although the nail will initially remain attached, proximal shedding will eventually occur.⁷ When several nails are involved, a systemic source—such as an acute infection, autoimmune disease, medication, malignancy (eg, cutaneous T-cell lymphoma), Kawasaki disease, skin disorders (eg, pemphigus vulgaris or keratosis punctata et planters), or chemotherapy—may be the cause.^6-8 If only a few nails are involved, it may be associated with trauma, and in rare cases, onychomadesis can be idiopathic.^5,7

In this case, all signs pointed to onychomadesis. All of the patient’s nails were affected (discolored and lifting), his nail loss involved spontaneous proximal separation of the nail plate from the nail matrix, and he had a recent previous infection: HFMD.

DISCUSSION

Onychomadesis is a rare nail-shedding disorder thought to be caused by the temporary arrest of the nail matrix.⁸ It is a potential late complication of infection, such as HFMD,⁹ and was first reported in children in Chicago in 2000.¹⁰ Since then, onychomadesis has been noted in children in many countries.⁸ Reports of onychomadesis following HFMD in adults are rare, but it may be underreported because HFMD is more common in children and symptoms are usually minor in adults.¹¹

Onychomadesis following hand-foot-mouth disease (HFMD) may be underreported in adults because HFMD is more common in children and symptoms in adults are minor.

Molecular studies have associated onychomadesis with coxsackievirus (CV)A6 and CVA10.⁴ Other serotypes associated with onychomadesis include CVB1, CVB2, CVA5, CVA16, and enteroviruses 71 and 9.⁴ Most known outbreaks seem to be caused by CVA6.⁴

No treatment is needed for onychomadesis; physicians can reassure patients that normal nail growth will begin within 1 to 4 months. Because onychomadesis is rare, it does not have its own billing code, so one can use code L60.8 for “Other nail disorders.”¹²

Our patient was seen in the primary care clinic 3 months after his initial visit. At that time, his nails were no longer discolored and no other abnormalities were present. All of the nails on his fingers and toes were firmly attached and growing normally.

THE TAKEAWAY

The sudden asymptomatic loss of multiple fingernails and toenails—especially with proximal nail shedding—is a rare disorder known as onychomadesis. It can be caused by various etiologies and can be a late complication of HFMD or other viral infections. Onychomadesis should be considered when evaluating older patients, particularly when all of their nails are involved after a viral infection.

CORRESPONDENCE
Jon F. Peters, MD, MS, FAAFP, 14486 SE Lyon Court, Happy Valley, OR 97086; peters-nw@comcast.net