Response to 'No evidence of SARS-CoV-2 infection by polymerase chain reaction or serology in children with pseudo-chilblain'. Reply from the authors

Paucity of cutaneous manifestations of COVID-19 among inpatients in a referral hospital in India

Background

Varied cutaneous manifestations of COVID-19 have been described, but most studies are based on photographic or application-based observations, without a direct observed-based evaluation by dermatologists.

Objective

To study the types of cutaneous manifestations of COVID-19 among confirmed inpatients admitted to COVID-19 wards and intensive care units (ICUs).

Methods

This cross-sectional analysis was conducted at a referral hospital in Delhi, India. Four hundred forty consecutive reverse transcription-polymerase chain reaction (RT-PCR)–confirmed cases diagnosed with moderate or severe COVID-19 and admitted to COVID-19 wards or ICUs, respectively, were included. A cutaneous finding was considered to be associated with COVID-19 if it had been described earlier as a consequence of COVID-19 and was observed at the time of or within the first 48 hours of admission (after excluding drugs and comorbidities as causes).

Results

Two hundred seventy patients with moderate COVID-19 were admitted to COVID-19 wards, whereas 170 with severe disease were admitted to ICUs. Only 7 of the 270 ward patients (2.59%) and 3 of the 170 ICU patients (1.76%) had cutaneous findings associated with COVID-19.

Conclusion

Cutaneous findings attributable to COVID-19 are infrequent, and we believe that these might have been overestimated or overemphasized in earlier studies. Although coagulopathic findings may be associated with severe COVID-19, causation cannot be established in this cross-sectional study.

Chilblains during lockdown are associated with household exposure to SARS-CoV-2: a multicentre case-control study

Objectives

During the COVID-19 pandemic, numerous cases of chilblains have been reported. However, in most cases, RT-PCR or serology did not confirm SARS-CoV-2 infection. Hypotheses have been raised about an interferon-mediated immunological response to SARS-CoV-2, leading to effective clearance of the SARS-CoV-2 without the involvement of humoral immunity. Our objective was to explore the association between chilblains and exposure to SARS-CoV-2.

Methods

In this multicentre case–control study, cases were the 102 individuals referred to five referral hospitals for chilblains occurring during the first lockdown (March to May 2020). Controls were recruited from healthy volunteers' files held by the same hospitals. All members of their households were included, resulting in 77 case households (262 individuals) and 74 control households (230 individuals). Household exposure to SARS-CoV-2 during the first lockdown was categorized as high, intermediate or low, using a pre-established algorithm based on individual data on symptoms, high-risk contacts, activities outside the home and RT-PCR testing. Participants were offered a SARS-CoV-2 serological test.

Results

After adjustment for age, the association between chilblains and viral exposure was estimated at OR 3.3, 95% CI (1.4–7.3) for an intermediate household exposure, and 6.9 (2.5–19.5) for a high household exposure to SARS-CoV-2. Out of 57 case households tested, six (11%) had positive serology for SARS-CoV-2, whereas all control households tested (n = 50) were seronegative (p = 0.03). The effect of potential misclassification on exposure has been assessed in a bias analysis.

Discussion

This case–control study demonstrates the association between chilblains occurring during the lockdown and household exposure to SARS-CoV-2.