Recurrent Onychomadesis of the Toenails in Children and Adults: A Case Series

• Onychomadesis has been attributed to viral infections, autoimmune disorders, drug side effects, and physical trauma.

• A subset of patients has a recurrent form of onychomadesis without a clear trigger.

• Certain cases of recurrent onychomadesis with no previously identified etiology may be due to microtrauma.

• Urea 40% cream is a helpful treatment.

Onychomadesis is proximal separation of the nail plate from the nail matrix and nail bed. It is a severe form of Beau’s lines, which result from interruptions in nail matrix cell proliferation due to trauma or illness [1]. Onychomadesis has been attributed to viral infections (particularly coxsackieviruses), autoimmune disorders, drug side effects, and physical trauma, but some cases have no known etiology [2-5]. Involvement of the toenails may be more prevalent in athletes, particularly runners [5].

A subset of patients has a recurrent form of onychomadesis without a clear trigger [6]. These nail changes can be distressing for patients and/or guardians. Information about treatment, natural history, and detailed risk factors is lacking in the literature. To fill this gap, we reviewed our known cases of recurrent onychomadesis.

This work was conducted at Washington University School of Medicine in St. Louis, St. Louis, MO, USA, and the University of Bologna, Bologna, Italy. The Institutional Review Board of Washington University School of Medicine (St. Louis, MO, USA) and the Ethics Committee of the University of Bologna (Bologna, Italy) approved this retrospective case series. Data were gathered via chart abstraction. Cases of onychomadesis were considered recurrent if they had multiple layers of nails separated proximally from the nail bed. Herein, we present 11 pediatric (ages <18 years) and 40 adult patients with recurrent onychomadesis of the toenails (data in Table 1).

All patients had involvement of the great toes, which in all cases were their longest toes. Morphology was remarkably similar – multilayered onychomadesis caused thickening of the affected nails, with moderate (shown in Fig. 1a) or marked (shown in Fig. 1b) hyperkeratosis. Forty-four (86%) patients had bilateral involvement. Two patients had involvement of the second toes (shown in Fig. 1a), in addition to the great toes. No patients had fingernail involvement. Twenty-seven (53%) patients participated in active hobbies or sports. Four patients (8%, all children) had anatomic anomalies of the feet, 3 with congenital malalignment of the great toes and one with pes planus. Two children had neuromuscular and neurological diagnoses.

Urea cream (20–40%, 44/47 using 40%) was the primary treatment. Urea 40% cream produced improvement in 32/44 (73%) patients. One patient had improvement after bilateral great toenail avulsion, but the nails did not completely normalize. No patient had recent history of viral infection, documentation of an autoimmune diagnosis, nor known potential causative medications, making infectious, autoimmune, and drug triggers less likely.

For this series of 51 patients with recurrent onychomadesis of the toenails, we propose microtrauma associated with footwear as the underlying cause as all cases had involvement of the longest toe(s). Notably, many patients participated in active hobbies or sports, including running. Four cases had anatomic abnormalities of the feet, which may further support a traumatic etiology. The lateral deviation of nails in congenital malalignment of the great toenails (seen in 3 cases) can predispose these patients to microtrauma [7]. Many patients saw improvement with application of urea 40% cream, which promotes softening, enables trimming, and facilitates chemical avulsion when desired [8].

One pediatric patient had dystrophic nails since birth. There are reports of a rare genetic form of onychomadesis, including one of a mother and daughter with the condition [9]. In our case, no other family members had the condition. This study is limited by its retrospective nature. Some data points, including anatomic abnormalities and involvement in sports, may not have been documented in patient charts.

Recurrent onychomadesis may be underrecognized. This series illustrates the spectrum of clinical findings in this condition, from thin layering to marked hyperkeratosis. Due to the periodicity of nail shedding and exclusion of other possible etiological factors, the cases herein were most likely trauma induced. The cornerstone of treatment is to minimize injury to affected digits. Urea 40% cream can be part of this strategy, as it can make the nail smoother and more resistant to trauma.

This study protocol was reviewed and approved by the Institutional Review Board of Washington University School of Medicine (St. Louis, MO, USA) and the Ethics Committee of the University of Bologna (Bologna, Italy). Institutional Review Board ID number: 201911013. No identifiable photos or data are included, and therefore consent was not necessary. The study approval included the waiver of the need for written informed consent from the patients to publish the case series and any accompanying images.

The authors declare no conflicts of interest.

No funding was received for this manuscript.

Dana Sous contributed to design of the work, acquisition and interpretation of data, drafting of the manuscript, and coordination of revisions. Michela V.R. Starace contributed to acquisition and interpretation of data and critical revision of the manuscript. Lu Chen, Elizabeth L. Nieman, Milan J. Anadkat, and Bianca Maria Piraccini contributed to interpretation of data and critical revision of the manuscript. Carrie C. Coughlin contributed to design of the work, acquisition and interpretation of data, and critical revision of the manuscript. All authors approved the final version of the manuscript and agree to be accountable for the work.

The data that support the findings of this study are not publicly available due to the potential for patient identification in this case series, but are available in aggregate from the corresponding author (C.C.C.).