The pathogenesis of coronavirus disease 2019 (COVID-19), the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is not yet completely understood. Thus far, it is known to affect multiple organ systems, including gastrointestinal, neurological, and cardiovascular, with typical clinical symptoms of COVID-19 including fever, cough, myalgia, headache, anosmia, and diarrhea.1 This multiorgan attack may be secondary to an exaggerated inflammatory reaction with vasculopathy and possibly a hypercoagulable state. Skin manifestations also are prevalent in COVID-19, and they often result in polymorphous presentations.2 This article aims to summarize cutaneous clinical signs of COVID-19 so that dermatologists can promptly identify and manage COVID-19 and prevent its spread.
Methods
A PubMed search of articles indexed for MEDLINE was conducted on June 30, 2020. The literature included observational studies, case reports, and literature reviews from January 1, 2020, to June 30, 2020. Search terms included COVID-19, SARS-CoV-2, and coronavirus used in combination with cutaneous, skin, and dermatology. All of the resulting articles were then reviewed for relevance to the cutaneous manifestations of COVID-19. Only confirmed cases of COVID-19 infection were included in this review; suspected unconfirmed cases were excluded. Further exclusion criteria included articles that discussed dermatology in the time of COVID-19 that did not explicitly address its cutaneous manifestations. The remaining literature was evaluated to provide dermatologists and patients with a concise resource for the cutaneous signs and symptoms of COVID-19. Data extracted from the literature included geographic region, number of patients with skin findings, status of COVID-19 infection and timeline, and cutaneous signs. If a cutaneous sign was not given a clear diagnosis in the literature, the senior authors (A.L. and J.J.) assigned it to its most similar classification to aid in ease of understanding and clarity for the readers.
Results
A search of the key terms resulted in 75 articles published in the specified date range. After excluding overtly irrelevant articles and dermatologic conditions in the time of COVID-19 without confirmed SARS-CoV-2 infection, 25 articles ultimately met inclusion criteria. Relevant references from the articles also were explored for cutaneous dermatologic manifestations of COVID-19. Cutaneous manifestations that were repeatedly reported included chilblainlike lesions; acrocyanosis; urticaria; pityriasis rosea–like cutaneous eruption; erythema multiforme–like, vesiculopapular, and morbilliform eruptions; petechiae; livedo reticularis; and purpuric livedo reticularis (dermatologists may label this stellate purpura). Fewer but nonetheless notable cases of androgenic alopecia, periorbital dyschromia, and herpes zoster exacerbations also were documented. The Table summarizes the reported integumentary findings. The eTable groups the common findings and describes patient age, time to onset of cutaneous sign, and any prognostic significance as seen in the literature.
Chilblainlike Lesions and Acrocyanosis
Chilblainlike lesions are edematous eruptions of the fingers and toes. They usually do not scar and are described as erythematous to violaceous papules and macules with possible bullae on the digits. Skin biopsies demonstrate a histopathologic pattern of vacuolar interface dermatitis with necrotic keratinocytes and a thickened basement membrane. Lymphocytic infiltrate presents in a perieccrine distribution, occasionally with plasma cells. The dermatopathologic findings mimic those of chilblain lupus but lack dermal edema.3
These eruptions have been reported in cases of COVID-19 that more frequently affect children and young adults. They usually resolve over the course of viral infection, averaging within 14 days. Chilblainlike eruptions often are associated with pruritus or pain. They commonly are asymmetrical and appear more often on the toes than the fingers.4 In cases of COVID-19 that lack systemic symptoms, chilblainlike lesions have been seen on the dorsal fingers as the first presenting sign of infection.5
Acral erythema and chilblainlike lesions frequently have been associated with milder infection. Another positive prognostic indicator is the manifestation of these signs in younger individuals.3
Morbilliform Exanthem
The morbilliform exanthem associated with COVID-19 also typically presents in patients with milder disease. It often affects the buttocks, lower abdomen, and thighs, but spares the palms, soles, and mucosae.4 This skin sign, which may start out as a generalized morbilliform exanthem, has been seen to morph into macular hemorrhagic purpura on the legs. These cutaneous lesions typically spontaneously resolve.8