Rod Tucker discusses what research has uncovered about a link between skin rashes and Covid-19
Covid-19 has proven to be a complex condition, and one set of symptoms that have gained attention are the associated skin problems. In the first publication to describe the clinical signs and symptoms, among a group of 1,099 people from Wuhan, China, it was reported that just 0.2% of patients with Covid-19 reported cutaneous symptoms, though the article offered no specific details of what the authors had observed.
As case numbers rose across the world, routine clinical care in virtually all specialities came to a grinding halt, and specialists from a variety of different clinical areas were deployed to the front-line. It was only when this happened, that dermatologists, now working with Covid patients, started to notice some peculiar changes to the skin of infected patients.
The first detailed account of the cutaneous signs of Covid-19 were reported by a group of Italian dermatologists. After reviewing infected patient’s drug histories, and excluding 60 individuals who had been started on a new medicine within the past 15 days (which might have represented an adverse drug reaction), they were left with 88 patients. Within this sample, 20.4% (18) developed skin manifestations, including erythematous rashes, chicken pox-like reactions and widespread urticarias.
Other reports appeared detailing similar rashes, but mounting and supportive evidence that Covid-19 could lead to skin changes arose from an unlikely source.
In March 2020, a group from Kings’ College, London, established the COVID Symptom Study, in which infected patients could self-report their symptoms via a smartphone app. The study provided useful patient data, and as the number of people registering and reporting via the app increased, it was becoming clear that a fever and persistent cough, were not the only prominent Covid-19 symptoms.
Early on, based on symptoms reported through the app, the team campaigned for anosmia (loss of taste/smell) to be added to the main Covid-19 symptom list. In June 2020, with approximately 4 million people reporting their symptoms, the team first proposed that skin rashes be considered as a fourth key sign of Covid-19 infection.
In data published from the group, which included over 330,000 people, it was found that 17% of those who tested positive for Covid-19 described a skin rash as the first symptom of infection. Furthermore, 21% of those who stated that they developed a rash as the only symptom were later confirmed to be infected with Covid-19.
Skin rashes and Covid-19
Given this clear evidence that skin rashes can be associated with Covid-19, what should the pharmacy team continue to look out for, especially given the fact that this can be the only symptom in an otherwise healthy person?
The most commonly-described skin changes in people with Covid-19 include:
Commonly affecting the trunk or limbs but sometimes the face, in around 20% of cases. Furthermore, one case study reported a patient initially presenting with odynophagia (difficulty swallowing) and an urticarial rash on the hands and face before the onset of other Covid-19 symptoms.
This most commonly affects acral surfaces such as the toes: it has become known as Covid toes, and resembles chilblains. When this condition was first observed in those with Covid-19, it was somewhat puzzling. Chilblains are commonly seen in patients during the colder weather and in those poor circulatory conditions such as Raynaud’s’ syndrome. These lesions were appearing during the warmer spring weather and often in younger people. Given this paradox, dermatologists have felt that pseudo-chilblains were most likely to be caused by Covid-19. The condition can be asymptomatic, although in some patients it can result in both itch and tenderness, and sometimes occurs after the development of oedema.
An erythemato-papular rash or erythemato-vesicular (i.e., chicken-pox like) presentation consisting of small and pruritic blisters has been identified in several reports. The rash itself can be localised or even generalised to the whole body, and it seems that patients develop the rash at the onset of symptoms and can take up to 10 days to resolve.
These are purple coloured rashes caused by blood leaking into the skin, and have also been reported in patients with Covid-19.
Lesions occurring in the mouth, eyes and genitals have also been described.
Questioning patients
Although many of the above rashes can present due to a variety of other conditions, e.g., urticarias can be caused by an adverse drug reaction, pharmacy staff should always enquire about any other symptoms to try and rule out Covid-19. Nevertheless, the appearance of pseudo-chilblains should raise the index of suspicion that a patient has Covid-19.
Useful Covid-19 skin resources
British Association of Dermatologists Covid-19 Skin patterns
Centre for Evidence-based dermatology coronavirus dermatology resource
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