COVID-19 can nail you in so many ways

By Elizabeth Yim, MD, MPH, FAAD, and John Montgomery Yost, MD, MPH, FAAD
July 13, 2022
Vol. 4, No. 28

During these difficult and quite frankly, scary times, we have heard numerous reports of various cutaneous manifestations by the SARS-COV-2 infection (COVID-19), thanks to our colleagues. Much of the buzz have been reports of Covid toes, vesicular eruptions, urticarial, livedoid or retiform purpura eruptions. The pernio-like eruption is hypothesized to be a result of type 1 interferon response and endothelial dysfunction and activation. (1) We would like to point out that cutaneous findings reported in Fitzpatrick skin types (FST) III to V may be more subtle compared with FST I and II. (2)

Much less reported are findings on the nails that may be related to COVID-19 infection. The first manifestations reported is the red half-moon nail sign that occurs 2-14 days after diagnosis of covid infection. (3,4) It appears as an asymptomatic transverse convex red band located at the distal margin of the lunula. Transverse leukonychia have also been reported in a hospitalized patient 6 weeks after developing symptoms. (5) Other nail changes include Beau’s lines and onychomadesis (6), which typically occur 1-3 months after development of symptoms. An orange discoloration along distal nails have also been reported in patient four months after developing COVID-19 symptoms (7), and just as periungual desquamation has been reported in children with severe Kawasaki disease (and potentially with multi-system inflammatory syndrome in children, MIS-C) and adults recovering from severe COVID-19 infection. (8,9) Another late manifestation of nail findings reported is a heterogenous red-white discoloration of the nail bed with distal onycholysis. (10)

Although biopsies were not done in these case reports, the observed nail changes were hypothesized to be an indicator of microvascular injury likely complement-mediated or indicative of a procoagulant state resulting from an inflammatory immune response similar to what we observe in chilblains or “Covid toes.” Nailfold capillaroscopy in 82 hospitalized COVID-19 patients in Italy showed pericapillary edema, enlarged capillaries sludge flow and low capillary density. (11)

Although many of the case reports of nail signs in patients with COVID-19 infection are reported in adult patients between the ages of 37-89 years, we anticipate that there will be more reports in pediatric patients in the future. We also suspect that there will soon be a number of case reports of nail findings witnessed in patients receiving the COVID-19 mRNA vaccines. Dr. Lipner’s group from Cornell has already reported nail psoriasis being triggered by Pfizer-BioN Covid-19 mRNA vaccine. (12) Nail changes reported were onycholysis, subungual hyperkeratosis, and irregular nail pitting that were observed 7 days after the patient’s second vaccine dose.

Point to Remember: Nail findings are often a late manifestation of COVID-19 infection, usually appearing after symptoms have resolved. Dermatologists we should be aware of reported nail findings to help educate our patients and reassure them that these changes do not reflect active COVID-19 infection.

Our editor’s viewpoint

Warren R. Heymann, MD, FAAD

It is not surprising that nails are affected by COVID-19 — no organ or tissue is spared. The literature on this topic is well-reviewed by Drs. Yim and Yost. Some of the changes described would be expected (such as Beau’s lines, transverse leukonychia, and onychomadesis), as seen with any severe systemic illness. More specifically, COVID-19 has a potentially devastating effect on vasculature as the hyperinflammatory state caused by SARS-CoV-2 infection may result in endothelial dysfunction. In another study of nailfold microscopy in 31 patients with SARS-CoV-2 infection (25 COVID-19 and 6 MIS-C patients compared to 58 healthy controls) it was demonstrated that patients with MIS-C had a higher frequency of capillary ramification and neoangiogenesis compared with COVID-19 patients, allowing the authors to conclude that nailfold capillaroscopy is a simple, non-invasive method for evaluation of microvascular involvement. (13). There is so much more to learn about the cutaneous (and appendageal) manifestations of COVID-19. I was intrigued by the case report by Tammaro et al (7) of an 89-year-old woman who developed orange discolorations at the end of the fingernail beds 16 weeks after her acute infection. The etiology of this discoloration is unknown (the appearance reminded me of nicotine stains — I hope the patient did not take up smoking post-COVID-19!). Unfortunately, as I am writing this viewpoint, the pandemic is still with us, despite the administration of “booster” vaccines. The AAD COVID-19 registry is still open. Please report your patients’ findings so that these dermatologic oddities can continue to be sorted out.

1. Frumholtz L, Bouaziz JD, Battistella M, Hadjadj J, Chocron R, Bengoufa D, Le Buanec H, Barnabei L, Meynier S, Schwartz O, Grzelak L, Smith N, Charbit B, Duffy D, Yatim N, Calugareanu A, Philippe A, Guerin CL, Joly B, Siguret V, Jaume L, Bachelez H, Bagot M, Rieux-Laucat F, Maylin S, Legoff J, Delaugerre C, Gendron N, Smadja DM, Cassius C; Saint-Louis CORE (COvid REsearch). Type I interferon response and vascular alteration in chilblain-like lesions during the COVID-19 outbreak. Br J Dermatol. 2021 Oct 5. doi: 10.1111/bjd.20707. Epub ahead of print. PMID: 34611893.

2. Daneshjou R, Rana J, Dickman M, Yost JM, Chiou A, Ko J. Pernio-like eruption associated with COVID-19 in skin of color.JAAD Case Rep. 2020 Sep;6(9):892-897.

3. Neri I, Guglielmo A, Virdi A, Gaspari V, Starace M, Piraccini BM. The red half‐moon nail sign: a novel manifestation of coronavirus infection. J Eur Acad Dermatology Venereol 2020; 34: e663–e665.

4. Méndez-Flores S, Zaladonis A, Valdes-Rodriguez R. COVID-19 and nail manifestation: be on the lookout for the red half-moon nail sign. Int J Dermatol. 2020;59(11):1414.

5. Fernandez-Nieto D, Jimenez-Cauhe J, Ortega-Quijano D, Diaz- Guimaraens B, Dominguez-Santas M, Martinez-Rubio J. Transverse leukonychia (Mees' lines) nail alterations in a COVID-19 patient. Dermatol Ther. 2020;17:e13863

6. Alobaida S, Lam JM. Beau lines associated with COVID-19. Can Med Assoc J. 2020;192(36):E1040.

7. Tammaro A, Adebanjo GAR, Erasmus HP, et al. Transverse orange nail lesions following SARS-CoV-2 infection. Dermatol Ther. 2021;34(1):e14688

8. Lindsley CB. Nail-bed lines in Kawasaki disease. Am J Dis Child. 1992;146 (6):659-660.

9. Nakamoto T, Ishikane M, Sasaki R, Ohmagari N. Periungual desquamation in a Japanese adult recovering from severe COVID-19. Int J Infect Dis. 2021;102:37-39.

10. Demir B, Yuksel EI, Cicek D, Turkoglu S. Heterogeneous red-white discoloration of the nail bed and distal onycholysis in a patient with COVID-19. J Eur Acad Dermatol Venereol. 2021;35(9):e551-e553.

11. Natalello G, De Luca G, Gigante L, et al. Nailfold capillaroscopy findings in patients with coronavirus disease 2019: Broadening the spectrum of COVID-19 microvascular involvement. Microvasc Res. 2021;133:104071

12. Ricardo JW, Lipner SR. Case of de novo nail psoriasis triggered by the second dose of Pfizer-BioNTech BNT162b2 COVID-19 messenger RNA vaccine. JAAD Case Rep. 2021;17:18-20. 

13. Çakmak F, Demirbuga A, Demirkol D, Gümüş S, Torun SH, Kayaalp GK, Ömeroglu RE, Somer A, Uysalol M, Yıldız R, Ayaz NA. Nailfold capillaroscopy: A sensitive method for evaluating microvascular involvement in children with SARS-CoV-2 infection. Microvasc Res. 2021 Nov;138:104196. doi: 10.1016/j.mvr.2021.104196. Epub 2021 Jun 10. PMID: 34097919; PMCID: PMC8190529.

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