The story of COVID toes continues to unfold as covered in my previous blogs (click here and click here). I recently attended the PCDS Spring Meeting (online, of course) and was interested to see the presentation by Dr George Kravvas, a dermatologist from Bristol, discussing the dermatological manifestations of COVID 19 [1]. He opened the talk discussing the phenomenon we now know as COVID toes – chilblain-like lesions (pseudo-chilblains) which have frequently been observed over the pandemic. Of course, a question that has hung over the diagnosis has been are they really chilblains or a sign of COVID 19 exposure? Dr. Kravvas suggested that chilblains occurring over the warmer periods were certainly suspicious, particularly in those without a previous history of chilblains. He suggested a COVID test would be appropriate, even though frequently these tests are negative. Treatment is not needed in most cases, but topical steroids and analgesia may help for troublesome lesions. Typically, they heal within 14 days.
He went onto discuss a similar presentation that had been alluded to in the recent literature by Mehta and colleagues [2]. They report a subset of patients (both adults and children), who appear to have more persistent digital lesions. This was first reported last year in a small group of 6 patients whose chilblains lasted over 60 days (click here). The lesions resemble the vasculopathy sometimes observed in rheumatological diseases. Where lesions persist for more than a month, they recommend further investigations to rule out other causes, which may possibly have been triggered initially by the COVID-19 infection. Routine blood screening can be helpful here including anti-nuclear antibodies (ANA), extracted nuclear antigen (ENA) and antineutrophil cytoplasmic antibodies (ANCA). Typically, patients present with chilblain-like lesions on a dusky blue background similar to acrocyanosis. Limbs typically may be described by patients as burning hot forcing them to immerse them in cold water. This can be counterproductive as it may exacerbate the condition further.
Nailfold Capillary Abnormalities seen under dermoscopy as reported by Natalello (3)
Dermoscopy can also be helpful in these cases. By studying the nail fold capillaries (also known as capillaroscopy) can demonstrate any changes. A study by Natallelo and colleagues [3] of the nail folds of COVID patients (acute and recovered) demonstrated that acute disease showed microhaemorrhages and capillary oedema compared to recovered patients who mainly demonstrated swollen capillaries in reduced numbers. The suggested treatment for long COVID chilblains to date has been suggested as topical steroids, oral aspirin and vasodilators such as nifedipine [2].
References
1. Kravvas, G. Skin manifestations of COVID 19. in Primary Care Dermatology Society Spring Meeting. 2021. Online: PCDS.
2. Mehta, P., et al., Chilblain-like acral lesions in long COVID-19: management and implications for understanding microangiopathy. The Lancet Infectious Diseases, 2021.
3. Natalello, G., et al., Nailfold capillaroscopy findings in patients with coronavirus disease 2019: Broadening the spectrum of COVID-19 microvascular involvement. Microvascular Research, 2021. 133: p. 104071. https://doi.org/10.1016/j.mvr.2020.104071