Evaluation of Chilblains as a Manifestation of the COVID-19 Pandemic

Abstract

Importance: During the coronavirus disease 2019 (COVID-19) pandemic, several cases of chilblains have been reported.

Objective: To determine if chilblains are associated with COVID-19.

Design, setting, and participants: This monocentric case series was conducted at the Department of Dermatology at Cliniques universitaires Saint-Luc, a tertiary care hospital in Brussels, Belgium, between April 10 and April 17, 2020. We evaluated a total of 31 referred patients who had recently developed chilblains.

Main outcomes and measures: Real-time reverse transcriptase-polymerase chain reaction (RT-PCR) was used to detect severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA on nasopharyngeal swabs for all patients and in skin biopsy specimens for 22 patients. Blood samples from all patients were tested for specific anti-SARS-CoV-2 immunoglobulin (Ig) M and IgG antibodies. All patients had extended blood analyses. Histologic (22 patients) and immunofluorescence examinations (15 patients) were performed on the skin biopsy specimens.

Results: The 31 patients were generally in good health; most were teenagers or young adults, and 19 were women. Histopathologic analysis of skin biopsy specimens (22 patients) confirmed the diagnosis of chilblains and showed occasional lymphocytic or microthrombotic phenomena. Immunofluorescence analyses showed vasculitis of small-diameter vessels in 7 patients. In all patients, SARS-CoV-2 RNA remained undetected by RT-PCR on nasopharyngeal swabs and in biopsy samples of the skin lesions. The IgM and IgG antibody titers were negative for SARS-CoV-2 in all patients (<1.0 arbitrary unit/mL). No significant abnormalities in blood test results were suggestive of systemic disease. Antinuclear antibody titers were low in 7 patients and higher in 1 patient.

Conclusions and relevance: Chilblains appeared not to be directly associated with COVID-19 in this case series. Lifestyle changes associated with community containment and lockdown measures are a possible explanation for these lesions.

Figure 1.. Clinical Aspects of Chilblains Observed

A, Patient 15 had erythematous macules as well as bullous lesions on the second and fourth toes of the left foot. B, Patient 20 had purplish erythematous macules located in the periungual area of all toes and some erythematous macules on the backs of the feet, at the root of some toes. C, Patient 18 had purplish erythematous macules on all toes, vesicular in places, with some additional lesions on the backs of the feet. D, Patient 10 had discrete periungual, annular erythematous lesions, vesicular at the center, on the second and third toes. E, Patient 13 had purplish erythematous macular periungual lesions. F, Patient 1 had annular erythematous macules on the fourth and fifth fingers.

Figure 2.. Histopathologic Images of Skin Biopsy Specimens

A. The epidermis shows scattered necrotic keratinocytes and focal vacuolar alteration of the basal layer (hematoxylin-eosin, original magnification ×20). B, In some samples, full-thickness epidermal necrosis is seen with subepidermal cleavage (hematoxylin-eosin, original magnification ×10). C, All biopsy specimens reveal heavy perivascular lymphocytic infiltrates in the superficial and deep dermis; eccrine extension of the infiltrates is often present (hematoxylin-eosin, original magnification ×5). D, Some specimens show lymphocytic vasculitis (mural and perivascular infiltrates of lymphocytes) (hematoxylin-eosin, original magnification ×20).