key: cord-0877498-0s71d9un
authors: Hadeler, E.; Morrison, B.W.; Tosti, A.
title: A review of nail findings associated with COVID‐19 infection
date: 2021-07-12
journal: J Eur Acad Dermatol Venereol
DOI: 10.1111/jdv.17448
sha: f81aff13efd096f0a9c527393e112b3afd045628
doc_id: 877498
cord_uid: 0s71d9un

According to recent data, up to 20% of patients with COVID-19 have cutaneous manifestations. Nails can also develop abnormalities during and after infection. In this article, we review the nail findings observed in patients with COVID-19.

and discharged patients, providing visual evidence of a vascular pathogenic component to COVID-19 infection.

Chilblain-like lesions are a commonly reported manifestation involving the digits. They are also known as 'COVID toes,' even though they can also affect fingers, and they present as erythematous, purpuric, papules and macules on the dorsal phalanges, nail folds and digital pulps (Figure 1b) . Chilblain-like lesions are predominantly found in children and adolescents. Nail findings have been reported in association with chilblain-like lesions. In a prospective study conducted by Docampo-Simon et al., two patients with chilblain-like lesions also presented with paronychia. 3 A causative link between COVID-19 and chilblains has not been firmly established despite an increase in the prevalence of these lesions during the pandemic.

Studies suggest that this well-known manifestation of COVID-19 infection may be the consequence of an exacerbated INF-a response. Very few patients presenting with chilblain-like lesions have other symptoms of COVID-19 infection, and only a few test positive for the infection when presenting with the lesions. It has been suggested that the overproduction of INF-a, which is produced at declining rates with age, may lead to rapid control of viral infection, thereby protecting younger patients from more severe disease and resulting in lower rates of positive nasopharyngeal swabs. The study by Hubiche et al. 10 also demonstrates that an increase in INF-a in patients with chilblain-like lesions could help young patients clear the virus rapidly. Other nail findings described in patients with chilblains include periungual erythema, peeling around the nail, nail fold telangiectasia and erythematous macules around the distal nail folds.

Our review of the literature did not reveal an association of nail disease with poor outcome for patients. 

Beau's lines and leukonychia in a COVID-19 patient

Transverse leukonychia (Mees' lines) nail alterations in a COVID-19 patient

Are chilblain-like acral skin lesions really indicative of COVID-19? A prospective study and literature review

The red half-moon nail sign: a novel manifestation of coronavirus infection

COVID-19 and nail manifestation: be on the lookout for the red half-moon nail sign

Transverse orange nail lesions following SARS-CoV-2 infection

Heterogeneous red-white discoloration of the nail bed and distal onycholysis in a patient with COVID-19

Dermoscopy features of COVID-19-related chilblains in children and adolescents

Nailfold capillaroscopy findings in patients with coronavirus disease 2019: Broadening the spectrum of COVID-19 microvascular involvement

Clinical, laboratory, and interferon-alpha response characteristics of patients with chilblain-like lesions during the COVID-19 pandemic

The patients in this manuscript have given written informed consent to the publication of their case details.