Transverse erythronychia: A unique nail manifestation of COVID-19 infection and brief review of COVID-19 associated nail changes

Abstract

Over the past 2 years, a plethora of mucocutaneous manifestations have been described to be associated with coronavirus 2019 (COVID-19) infection. Nail changes attributed to COVID-19 have rarely been documented in the literature. We describe here a unique nail finding ‘transverse erythronychia’ due to COVID-19 and review the literature on the diverse nail pathology attributed to the disease.

Introduction

A gamut of mucocutaneous manifestations of COVID-19 disease has been described over the past year ranging from morbilliform, urticarial, vesicular, papulosquamous, petechial/purpuric eruptions, pernio-like lesions, livedo reticularis like rashes, and retiform purpura.^1,2 Nail unit manifestations of COVID-19 are mostly non-specific possibly caused by the sensitive nature of the nail matrix when impacted by trauma, inflammation, and hypercoagulability. We report here a unique nail predicament ‘transverse erythronychia’ following COVID-19 infection and review the literature on nail changes associated with this raging viral infection.

Case presentation

An otherwise healthy 38-year-old Indian lady presented to our facility to seek dermatological consultation regarding sudden discolouration of her nails about a week after recovering COVID-19. Approximately 23 days since the onset of symptoms, she noticed a strange patterned discolouration involving the fingernails of the left hand. On examination, we noticed linear red bands of width 2–3 mm, which was slightly convex distally and traversed the distal nail plate margin at the level of isthmus, between the lateral nail fold margins (Figure 1). This finding was observed to involve all fingernails of the left hand, few digits of right hand while the toe nails were completely spared. Her other medical and dermatological history was unremarkable. This characteristic nail presentation was diagnosed as ‘transverse erythronychia’ associated with COVID-19.

Figure 1.

Transverse erythronychia involving all fingernails of left hand and few of the right hand (a and b).

The more recognised ‘red lunula’ (reddish discolouration of the entire lunula) is associated with rheumatoid arthritis, systemic lupus erythematosus, alopecia areata, cardiac failure, hepatic cirrhosis, lymphogranuloma venereum, psoriasis, carbon monoxide poisoning, twenty-nail dystrophy, and reticulosarcoma. Red half-moon-shaped bands have been characteristically described as bordering the distal edge of lunula (‘red half-moon lunula’).

She was reassured about the benign and self-limiting nature of this condition. On follow-up after 3 months, the nail changes were not visualised.

Discussion

Erythronychia is a common and benign clinical entity characterised by red discolouration of the nails of one or multiple digits. Although the more commonly encountered ‘longitudinal erythronychia’ (extending from the proximal nail fold to the distal tip of the nail plate) is often idiopathic, it has also been associated with benign subungual tumours, malignant subungual tumours, and various cutaneous conditions and systemic diseases.³ The present description of transverse erythronychia has rarely been documented. This was first reported in four patients of Kawasaki disease.⁴ Chang et al.⁵ described a case of polydactylous transverse and longitudinal erythronychia in an elderly Caucasian male with a past of testicular carcinoma. Siragusa et al.⁶ had also previously documented similar transverse dyschromic changes in a patient of multiple system atrophy, where disturbances to microcirculatory homeostatic mechanisms secondary to multiple system atrophy were postulated to have a contributory role.

The red half-moon lunula is another novel and infrequently described manifestation of COVID-19 infection. The presentation includes appearance of a distally convex half-moon-shaped red band surrounding the distal margin of the lunula affecting all fingernails. Neri et al.⁷ first described this unique finding 2 weeks after onset of symptoms with confirmed COVID-19 diagnosis. On follow-up a month later, they noticed further widening of the bands. Méndez-Flores et al.⁸ reported the second demonstrating this sign, where the appearance was seen only 2 days after symptom onset and subsequently resolved within a week. These clinical findings are attributed to microvascular injury of the capillary network of the distal subungual arcade secondary to an inflammatory immune response and a procoagulant milieu associated with SARS-CoV-2 infection.^7,8 A similar pathomechanistic reasoning explains the occurrence of transverse erythronychia in COVID-19.

Another reported nail finding includes transverse orange nail lesions.⁹ It was noted to occur 16 weeks after COVID-19 symptoms onset, demonstrating an orange discolouration of the distal nail plate with a sharp demarcation line from unaffected area. However, unlike our case, Tammaro et al.⁹ observed a much later onset (almost 4 months) and non-resolution of the nail lesions at 1-month follow-up. Transverse leukonychia, onychomadesis, transverse grooving (Beau’s lines), and leukonychia have also been reported in a few cases. A much delayed onset, ranging from 28 to 112 days, characterised these lesions.^8,9 The clinical features of cases documenting COVID-19 associated nail changes are highlighted in Table 1.^7–13

Table 1.

Compilation of nail changes documented with COVID-19 infection.

Author/year	Country	No. of patients	Age	Sex	Comorbidities	Nail findings	Onseta (days)	Systemic symptoms of COVID-19	Hospitalisation	COVID-19 treatment received	Resolution
Neri et al./2020	Italy	1	60	F	None	Red half-moon lunula	14	Fever, cough, dyspnoea, anosmia, ageusia	Yes	HCQ, Lopinavir/Ritonavir, ceftriaxone, heparin, supplemental oxygen	Widening of bands after 1 month
Méndez-Flores et al./2020	Mexico	1	37	F	Not mentioned	Red half-moon lunula	2	Anosmia, cough, fever	No	Not mentioned	1 week
Tammaro et al./2021	Italy	1	89	F	Not mentioned	Transverse orange discolouration	112	Cough, asthenia	Not mentioned	Not mentioned	Unaltered at 1 month
Alobaida et al./2020	Saudi Arabia	1	45	M	Not mentioned	Beau’s lines	98	Diarrhoea, fever, and dyspnoea	No	Not mentioned	Not mentioned
Ide et al./2020	Japan	1	68	M	None	Beau’s lines, leukonychia, periungual desquamation	28	Fever, dyspnoea	Yes	Hydroxychloroquine, methylprednisolone	Not mentioned
Senturk et al./2021	Turkey	1	47	F	Hypertension, diabetes mellitus	Onychomadesis	84	Sore throat	Yes	Hydroxychloroquine, azithromycin, oseltamivir, ceftriaxone	Not mentioned
Fernandez-Nieto/2020	Spain	1	47	M	None	Transverse leukonychia	45	Mild COVID-19 bilateral pneumonia	Yes	Lopinavir/Ritonavir	Not mentioned
Present case	India	1	37	F	None	Transverse erythronychia	23	Fever, sore throat, cough, myalgia	No	Azithromycin, Doxycycline, vitamin C, Zinc, paracetamol	3 months

M: male; F: female.

^aCounted from onset of COVID-19 symptoms appearance.

Given the paucity of reports on nail changes in COVID-19 infection, we seek to add to the existing literature on this matter. Physicians involved in care of COVID-19 patients should continue to document observed mucocutaneous changes to better identify the diagnostic clues and understand the underlying pathophysiological mechanisms of this viral disease.

Conclusion

The evaluation of nails is often overlooked while carrying out general physical examination. Nail changes attributed to COVID-19 infection have been rarely documented in the literature. ‘Transverse erythronychia’ is a characteristic nail presentation, the presence of which should raise the suspicion of a retrospective diagnosis of COVID-19 infection.