It is well known that COVID-19 (SARS-CoV-2 virus) causes symptoms such as fever, sore throat, dry cough and shortness of breath. Not much has been reported with regards to if, and how, COVID-19 affects the skin except for a few sparse case reports in the medical literature.
Viral infections often cause rashes and COVID-19 seems to be no exception. While viruses such as chicken pox and measles cause a rash that is very distinctive and diagnostic of the disease, the skin manifestations of COVID-19 are quite varied and non-specific. The skin signs of COVID-19 infections are therefore not diagnostic of the disease but may alert a treating physician to help diagnose patients with mild or atypical symptoms and may prevent complications.
How does COVID-19 cause skin manifestations? 1
- It can be due to the direct effect of the body’s immune response to the virus resulting in a viral exanthem. This is a common rash that accompanies many viral infections and not just COVID-19.
- Systemic complications of COVID-19 can cause skin signs such as vasculitis (inflammation of blood vessels) and thrombi (blood clots) in blood vessels which could result in dry gangrene.
- COVID-19 can also increase the risk of drug reactions and drug interactions which can also result in skin signs.
Why is it important to be aware of skin signs in COVID-19?
Skin signs are probably overlooked in these patients because dermatologists might not be actively involved in the management of COVID-19 patients. Another reason why skin signs might be underreported is that doctors could be focused only on the respiratory signs and may be missing skin signs.
It is important to be aware that COVID-19 could potentially cause skin signs as it may lead to the diagnosis of patients with atypical symptoms and prevent patients from developing complications such as dry gangrene of a finger or toe. A severe drug reaction may also be potentially fatal. Thus, early recognition and prompt management of skin manifestations is imperative as it may prevent avoidable complications.
Clinical picture of skin signs in COVID-19:
Viral exanthem picture
Viral exanthems are divided into different groups according to their morphology (i.e. how they look on skin examination). The differently groups include the morbilliform rash, petechial/purpuric rash, urticarial rash and chicken pox-like blistering rash.
The skin signs in COVID-19 may mimic what is seen in other types of viruses such as the morbilliform rash which is classically seen in measles patients. Petechial rash is seen in other infections such as meningococcal meningitis. Urticarial rashes (resembling hives) have also been described in other viral and bacterial infections.2
Vasculitis and thrombi-related complications
There have been a few cases of finger or toe cyanosis (blue discolouration) with bullae (large blisters) and dry gangrene. Transient unilateral livedo reticularis (mottled, netlike purplish discolouration of the skin) of the leg has also been described. Rarely, red papules on the fingers have been seen that resemble lupus erythematosus (called chilblains lupus).
Drug-related rashes
Drugs have been trialled in COVID-19 patients as these may cause unwanted side-effects such as a drug rash. Chloroquine may cause itching and hair loss. Azithromycin and antiretrovirals may result in a morbilliform rash. Systemic corticosteroids may cause a myriad of skin signs such as bruising, stretch marks (striae) and acne.
Conclusion
COVID-19 is a systemic disease and one should have a holistic view and be aware that other organ systems such as the skin may also be infected. The skin may also alert one to the diagnosis and potential complications such as drug reactions.
References:
- Suchonwanit P, Leerunyakul K, Kositkuljorn C. Cutaneous manifestations in COVID-19: Lessons learned from current evidence. Journal of the American Academy of Dermatology (2020).
- Kang JH. Febrile Illness with Skin Rashes. Infect Chemother. 2015 Sep; 47(3): 155–166.
Classification of the cutaneous manifestations of COVID‐19: a rapid prospective nationwide consensus study in Spain with 375 cases. BJD 28th of April 2020. https://doi-org.ez.sun.ac.za/10.1111/bjd.19163