The clinical spectrum of Coronavirus Disease 2019 (COVID-19) continues to be described as it spreads globally. In addition to the most common clinical features of fever, cough and fatigue, the literature also describes five skin cutaneous manifestations common in patients with COVID-19 at various timepoints in the disease: pseudo-chillblains, maculopapular eruptions, vesicular, urticarial and vaso-occlusive lesions. Interestingly, in a recent worldwide review by Tan, Tam and Oh (2020) of 1211 patients with COVID-19 skin manifestations, 1172 (96.9%) patients were from Europe and the United States, and 39 (3.1%) were from Asian populations. This difference in prevalence could be due to underreporting in skin-of-colour populations as well as limited diagnostic tests for COVID-19 in certain regions.
Signs and symptoms
Tan et al. (2020) have classified skin manifestations into five major clinical patterns:
1. Pseudo-chillblains: acral areas of erythematous or violaceous papules (may physically resemble chillblains) that are asymmetrically distributed and are more common in young adults. Vesicles and pustules with purpuric areas are also described. These are most common among patients in Europe and the United States.
2. Maculopapular rash: associated with pruritus and predominantly involving the trunk.
3. Vesicular lesions: usually occurring at the onset of COVID-19 symptoms, usually involving the trunk. Herpetiform, varicella-zoster-like and monomorphic vesicle formation have been described.
4. Urticarial lesions: oedematous papules and plaques that disappeared within 24 hours, mostly on the trunk and occasionally palmar. More than 50% of affected patients were middle-aged women.
5. Vaso-occlusive lesions: netlike violaceous lesions consisting of irregularly broken macules with an annular patter (livedo racemosa), painful purpuric stellate lesions (retiform purpura), and ischaemic lesions on the digits or toes (acral ischaemia).
The current gold standard for diagnosis of COVID-19 is reverse transcriptase (RT) polymerase chain reaction (PCR) to detect SARS-CoV-2 viral ribonucleic acid (RNA).
Rashes containing macules and papules are the second most common cutaneous manifestation of COVID-19 and it is important to note that there have been reports of misdiagnosed cases of COVID-19 as viral illness in patients with a maculopapular rash. This is of importance in Southeast Asia where dengue virus is endemic and may have a similar presentation. Given the current pandemic, the presence of a maculopapular rash should prompt suspicion of COVID-19.
Complications and Prognosis
Pseudo-chillblains were the most common COVID-19 skin manifestation in Tan et al.’s study (2020). These lesions appeared in the later stages of COVID-19 and were associated with indolent disease progression. On the other hand, vaso-occlusive lesions were the least common and associated with poorer outcomes, including being at higher risk of severe
pneumonia requiring intensive care, elevated levels of D-dimer and disseminated intravascular coagulation (Galvan Casas et al., 2020; Zhang et al., 2020).
1. Tan, S. W., Tam, Y. C., & Oh, C. C. (2020). Skin manifestations of COVID-19: A worldwide review. JAAD international.
2. Galván Casas, C., Catala, A. C. H. G., Carretero Hernández, G., Rodríguez‐Jiménez, P., Fernández‐Nieto, D., Rodríguez‐Villa Lario, A., … & García‐Doval, I. (2020). Classification of the cutaneous manifestations of COVID‐19: a rapid prospective nationwide consensus study in Spain with 375 cases. British Journal of Dermatology, 183(1), 71-77.
3. Zhang, Y., Cao, W., Xiao, M., Li, Y. J., Yang, Y., Zhao, J., … & Li, T. S. (2020). Clinical and coagulation characteristics in 7 patients with critical COVID-2019 pneumonia and acro-ischemia. Zhonghua xue ye xue za zhi= Zhonghua xueyexue zazhi, 41(4), 302-307.