Chilblains is a common cutaneous finding during the COVID-19 pandemic: A retrospective nationwide study from France

To the Editor: Coronavirus disease 19 (COVID-19), a pneumonia associated with severe acute respiratory syndrome coronavirus 2 (SARS-Cov2), was first identified in Wuhan, China, in December 2019, and was characterized as a pandemic by the World Health Organization on March 11, 2020. Fever, dry cough, dyspnea, fatigue, anorexia, ageusia, and anosmia are common symptoms of COVID-19. Reported skin manifestations of COVID-19 include erythematous lesions, sometimes with dengue-like petechiae,¹ and urticaria and chickenpox-like vesicles.²

We performed a retrospective observational nationwide study of skin lesions encountered during the COVID-19 pandemic in France from March 18 to April 9, 2020, in an outpatient setting of French private practices. Patients gave informed consent for the publication of their photographs. The study enrolled 277 patients, half were male, and the median age was 27 years (range, 2-98 years).

The lesions were classified into 6 categories: urticarial in 26 (9%; Fig 1 , A), vesicular in 41 (15%; Fig 1, B), acral in 142 (51%; Fig 1, C), morbilliform in 25 (9%; Fig 1, D and E), petechial in 7 (3%), livedo reticularis in 4 (1%), and other types in 41 (15%). Some patients presented with cutaneous signs fitting in multiple categories (detailed in Table I ). Acral lesions were unexpectedly common (n = 142). Chilblain-like lesions were the most frequent of the acral lesions (106 of 142 [75%]; Fig 1, C; Supplemental Fig 1, available via Mendeley at https://doi.org/10.17632/2f9rpvh9vd.1). Vesicular acral (dyshidrosis-like) lesions were reported in 20 patients (14%). Acrodynia was present in 18 patients (6%), sometimes isolated.

Fig 1.

Different types of skin rashes observed during the COVID-19 pandemic: (A) urticaria-like; (B) vesicular or chickenpox-like; (C) chilblains; (D) maculopapular; and (E) pityriasis rosea-like.

Table I.

Characteristics of the patients

Characteristic∗	No. (%) or median (range)
All patients	277
Male sex	129/259 (50)
Age, y	27 (2-98)
SARS-Cov2 PCR test	34/277 (12)
Positive PCR test	25/34 (74)
Contact with a patient with COVID-19	31/277 (11)
Suggestive extracutaneous symptoms†	103/277 (37)
Fever	48/277 (17)
Respiratory symptoms	44/277 (16)
Anosmia/ageusia	18/277 (6)
Digestive symptoms	16/277 (6)
Acrodynia	18/277 (6)
Morbilliform lesions	25/277 (9)
Male sex	10/21 (48)
Age, y	29 (2-70)
Location of lesions
Trunk or limbs	25/25 (100)
Face	2/25 (8)
Acral lesions	142/277 (51)
Male sex	67/132 (51)
Age, y	27 (6-73)
Type of lesions
Chilblains	106 (75)
Dyshidrosis-like lesions	20 (14)
Other	16 (11)
Location of lesions
Hands	23/34 (68)
Feet	18/34 (53)
Vesicular lesion	41 (15)
Male sex	22/38 (58)
Age, y	43 (8-74)
Type and location of lesions
Vesicles/varicella-like lesions of the trunk and limbs	21 (51)
Acral dyshidrosis-like lesions	20 (49)
Livedo reticularis	4 (1)
Male sex	1/2 (50)
Age, y	15
Urticarial lesions	26 (9)
Male sex	13/23 (57)
Median age (range)	3 (2-23)
Location of lesions
Trunk and limbs	24 (92)
Face	2 (8)
Petechial lesions	7 (3)
Male sex	5/7 (71)
Age, y	21 (5-70)
Location of lesions
Diffuse	3/7 (43)
Acral	2/7 (29)
Limbs	2/7 (29)
Other types of lesions‡	41 (15)
Male sex	11/36 (31)
Median age (range)	40 (1-98)
Location of lesions, n (%)
Trunk and limbs	33/41 (80)
Face	8/41 (20)

PCR, Polymerase chain reaction; SARS-Cov2, severe acute respiratory syndrome coronavirus 2.

^∗Some patients presented with cutaneous signs fitting in multiple categories.

^†There were 19 patients who reported suggestive extracutaneous symptoms and contact with a patient with COVID-19.

^‡Including eczema-like, angiomatous, and annular lesions.

Among the 277 patients, 34 had a SARS-Cov2 polymerase chain reaction (PCR) test, of which 25 (74%) were positive, and 7 of these 25 (28%) had acral lesions. Among the patients without a positive PCR test, 115 patients had suggestive extracutaneous symptoms (detailed in Table I) or reported a close contact with a patient with COVID-19, or both. In addition, 59 patients had isolated chilblains (without any past history of chilblains and in the absence of cold exposure), without associated extracutaneous symptoms; this may suggest cutaneous symptoms of COVID-19, because this finding has been documented in some patients with a positive SARS-Cov2 PCR test in our case series and in 2 recently published case reports.^{3 , 4} Histologic examination of 3 chilblain-like lesions showed a lichenoid dermatitis with a perivascular and eccrine mononuclear infiltrate and vascular microthrombi in 2 cases.

Owing to the retrospective, outpatient setting and the limited number of available SARS-Cov2 PCR tests in France to date, most patients were not tested. However, the number of observed chilblain-like lesions in patients without significant past medical history is extremely unusual during the spring season in France, especially because people are staying inside, and may suggest a link with COVID-19.

Finally, the presence of microthrombi in patients with chilblains is consistent with the altered coagulation status observed in patients with severe COVID-19.⁵ Although the number of tested patients does not allow us to draw firm conclusions regarding a direct link between SARS-Cov2 and these skin lesions, the unexpected outbreak of acral skin lesions in this epidemic context requires further investigation.