With the onset of the pandemic in January 2020, we began to learn the effects of the COVID 19 virus went well beyond just being a respiratory infection. Reports began to emerge in the spring of that year about its cutaneous manifestations including the much-discussed phenomenon of chilblain-like lesions [1] colloquially dubbed “COVID toes” [2]. Following this, a flurry of papers ensued describing cases of chilblains – in excess of the normally expected numbers for a springtime and in previously unaffected, younger populations [3-8]. Studies of Google searches also highlighted a significant spike in searches related to chilblains in the early part of 2020 [9].
Gradually, scientific theory began to unravel the mystery [10, 11] as the pandemic moved into new waves with the emergence of the alpha, beta, gamma, delta and omicron strains of the virus along with the vaccination programme. A recent UK based study [12] published in the British Journal of Dermatology investigated the cutaneous manifestations of the COVID-19 infection as new strains emerged. The study retrospectively examined data collected from the ZOE COVID study app, which was downloaded by the public and recorded patient reported data throughout the pandemic and subsequent waves.
The researchers particularly wanted to examine and compare skin signs during the delta and omicron waves. They focussed on five common skin manifestations of COVID-19 infection:
• Chilblain like lesions (acral lesions)
• A rash accompanied by burning paraesthesia
• A rash on the arms or torso
• Urticarial rash on the body or face
• Unusual hair loss
The study app collected patient entered data along with their COVID test status, any reported symptoms and latterly when they had had their vaccination. The data set consisted of over 348 000 users including nearly 43 000 confirmed COVID infections and 156 000 other (non-related) illnesses. Skin related symptoms were reported by 17.6% (Delta wave) and 9.6% of participants (Omicron wave) with skin symptoms having a shorter duration in the later wave. The researchers noted that reported acral lesions declined from 3.1% (during the initial wave) to 1.1% (delta wave) to 0.7% (omicron wave). Generally, the type of cutaneous symptoms were similar in both the vaccinated and unvaccinated groups, except for the burning rash which was less common after vaccination.
This study suggests that COVID toes may be reducing as new variants of COVID infection emerge. This has been anecdotally noted in an earlier paper [13] which suggested that the numbers of new chilblains cases being reported to dermatologists is falling to near pre-pandemic rates. Of course, this may be down to increased awareness amongst patients not consulting when they observe it or possibly due to the effects of vaccination [14]. This concurs with the UK study, which is based on patient reported rates, so potentially reinforces this theory. Of course, further work would be required to prove this but only time will tell.
Image Courtesy of C.Webb
References
1. Mazzotta, F. and E. Bonifazi, A new vasculitis at the time of Covid-19. Dermatologia Pediatrica, 2020.
2. Bristow, I.R. and A.M. Borthwick, The mystery of the COVID toes - turning evidence-based medicine on its head. J Foot Ankle Res, 2020. 13(1): p. 38.
3. Alramthan, A. and W. Aldaraji, A case of COVID-19 presenting in clinical picture resembling chilblains disease. First report from the Middle East. Clinical and Experimental Dermatology, 2020. n/a(n/a).
4. Nirenberg, M.S. and M. del Mar Ruiz Herrera, Foot Manifestations in a COVID-19 Positive Patient: A Case Study. Journal of the American Podiatric Medical Association, 2020.
5. Landa, N., et al., Chilblain-like lesions on feet and hands during the COVID-19 Pandemic. International Journal of Dermatology, 2020. 59(6): p. 739-743.
6. el-Azhary, R., Re: Chilblain-like lesions on feet and hands during the COVID-19 pandemic. International Journal of Dermatology, 2020. 59(6): p. 748-748.
7. Andina, D., et al., Chilblains in children in the setting of COVID-19 pandemic. Pediatric Dermatology, 2020. 37(3): p. 406-411.
8. Bascuas-Arribas, M., et al., Evolution of incidence of chilblain-like lesions in children during the first year of COVID-19 pandemic. Pediatric Dermatology, 2022. 39(2): p. 243-249.
9. Hughes, M., et al., Further evidence that chilblains are a cutaneous manifestation of COVID-19 infection. Br J Dermatol, 2020.
10. Battesti, G., et al., New insights in COVID-19-associated chilblains: a comparative study with chilblain lupus erythematosus. Journal of the American Academy of Dermatology, 2020.
11. Lipsker, D., A chilblain epidemic during the COVID-19 pandemic. A sign of natural resistance to SARS-CoV-2? Med Hypotheses, 2020. 144: p. 109959.
12. Visconti, A., et al., Cutaneous Manifestations of SARS-CoV-2 infection during the Delta and Omicron waves in 348,691 UK users of the UK ZOE COVID Study App. British Journal of Dermatology, 2022. n/a(n/a).
13. Willyard, C., Are 'COVID toes' actually caused by the coronavirus? Nature, 2022. 603(7903): p. 779.
14. Roberts, M. Study reveals why some people get Covid toe condition. [BBC News Website] 2021 [cited 2022 December]; Available from: https://www.bbc.co.uk/news/health-58801462.