Most chilblains observed during the COVID‐19 outbreak occur in patients who are negative for COVID‐19 on polymerase chain reaction and serology testing*

Abstract

Summary Background Acral lesions, mainly chilblains, are the most frequently reported cutaneous lesions associated with COVID‐19. In more than 80% of patients tested, nasopharyngeal swabs were negative on reverse transcription polymerase chain reaction (RT‐PCR) for SARS‐CoV‐2 when performed, and serology was generally not performed. Methods A national survey was launched on 30 March 2020 by the French Society of Dermatology asking physicians to report cases of skin manifestations in patients with suspected or confirmed COVID‐19 by using a standardized questionnaire. We report the results for acral manifestations. Results We collected 311 cases of acral manifestations [58.5% women, median age 25.7 years (range 18–39)]. The most frequent clinical presentation (65%) was typical chilblains. In total, 93 cases (30%) showed clinical suspicion of COVID‐19, 67 (22%) had only less specific infectious symptoms and 151 (49%) had no clinical signs preceding or during the course of acral lesions. Histology of skin biopsies was consistent with chilblains. Overall, 12 patients showed significant immunological abnormalities. Of the 150 (48%) patients who were tested, 10 patients were positive. Seven of 121 (6%) RT‐PCR‐tested patients were positive for SARS‐CoV‐2, and five of 75 (7%) serology‐tested patients had IgG anti‐SARS‐CoV‐2. Tested/untested patients or those with/without confirmed COVID‐19 did not differ in age, sex, history or acral lesion clinical characteristics. Conclusions The results of this survey do not rule out that SARS‐CoV‐2 could be directly responsible for some cases of chilblains, but we found no evidence of SARS‐CoV‐2 infection in the large majority of patients with acral lesions during the COVID‐19 lockdown period in France. What is already known about this topic? About 1000 cases of acral lesions, mainly chilblains, were reported during the COVID‐19 outbreak. Chilblains were reported to occur in young people within 2 weeks of infectious signs, which were mild when present. Most cases did not have COVID‐19 confirmed by reverse transcription polymerase chain reaction (RT‐PCR), and few serology results were available. What does this study add? Among 311 patients with acral lesions, mainly chilblains, during the COVID‐19 lockdown period in France, the majority of patients tested had no evidence of SARS‐CoV‐2 infection. Overall, 70 of 75 patients were seronegative for SARS‐Cov‐2 serology and 114 of 121 patients were negative for SARS‐CoV‐2 RT‐PCR.

COVID toes: where do we stand with the current evidence?

“…( Baeck et al, 2020c , Ko et al, 2020 ). Conversely, RT-PCR and anti-SARS-CoV-2 serology were mostly negative ( Herman et al, 2020 , Baeck et al, 2020a , Caselli et al, 2020 , El Hachem et al, 2020 , Neri et al, 2020 , Roca-Ginés et al, 2020 , Rouanet et al, 2020 , Rizzoli et al, 2020 , Mahieu et al, 2020 , García-Legaz Martínez et al, 2020 , Garcia-Lara et al, 2020 , Freeman et al, 2020b , Colonna et al, 2020 , Le Cleach et al, 2020 , Lesort et al, 2020 , Stavert et al, 2020 , Denina et al, 2020 ). Negative RT-PCR on nasopharyngeal swabs could suggest that chilblains are a late symptom of COVID-19.…”

COVID‐19 cutaneous manifestations: simplifying the confusion

“…However, most of these acral chilblain lesions showed negative COVID-19 PCR and serology and they resolved on their own. 3,4 With further pathology, immunohistochemistry and electron microscopy studies, [5][6][7][8] This pathophysiology was also shown to be similar to that occurring in the lung. 5 The retiform-like purpuric lesions are an advanced form of the coagulopathies with thrombi in larger vessels which could lead to strokes, pulmonary emboli, and an elevated D-Dimer with a poorer prognosis.…”

Negative tests for SARS‐CoV‐2 infection do not rule out its responsibility for chilblains

“…They hypothesized that the situation could be due to the media stating that chilblains were caused by SARS-CoV-2 infection and leading to a higher rate of consultation or the lockdown leading to more inactivity and long periods at home barefoot on a cold floor. 1 We do not agree with this explanation. We recently published cases of chilblains enrolled during the COVID-19 pandemic.…”

“…Negative tests for SARS-CoV-2 infection do not rule out its responsibility for chilblains DOI: 10.1111/bjd.19483 DEAR EDITOR, We read with great interest the report of Le Cleach et al discussing chilblains as a manifestation of the COVID-19 pandemic. 1 They reported 311 patients with acral lesions occurring during the COVID-19 lockdown in France. The most frequent clinical presentation of these acral lesions was typical chilblains.…”