A few weeks ago, the peculiar symptom of loss of smell and taste was reported as an early symptom of COVID-19 infection. This generally preceded the lung symptoms, the most prominent finding in the infection. Now more unexpected symptoms are being reported, including diarrhea, heart involvement, strokes, and skin rashes.
In one report from Italy, 20% of the patients had a skin rash, half at the onset of illness, and half later. There was not one specific type of rash; some were like hives, others a lacy pattern called livedo reticularis, and others were described as “chilblains” or “pernio,” with frostbite like lesions, and some were even like chickenpox.
What should you do if you develop such an odd rash? If you are not otherwise ill, self-quarantine for fourteen days, in case you have COVID-19. There is no point in going to the doctor for this—we still don’t have accurate tests to diagnose COVID-19, and you risk either infecting yourself or others by going out needlessly. You should seek care immediately if you are seriously ill, but not otherwise.
Sebastiano Recalcati, MD, from the Alessandro Manzoni Hospital in Lecco, Italy, described some of the early cases. In his series, the rash was more commonly on the trunk, and there was minimal or no itching. In a more recent series, the lesions were primarily on the fingers or toes. Biopsies showed some lymphocytic (type of blood cell) infiltration around blood vessels.
Dr. Ramon Grimalt, dermatology professor at UIC-Barcelona, also provided early reports from Spain noting that children and teens were being seen with pernio, or chilblains, of fingers and toes. These lesions are caused by cold, which causes inflammation of blood vessels in the skin in some people. These kids generally had no or few respiratory or other symptoms of COVID-19. The Spanish General Council of Official Colleges of Podiatrists opened a registry to collect all these unusual cases. They warned that while these skin lesions were benign (not a problem, in themselves) they were notable as a sign of asymptomatic infection with coronavirus. The American Academy of Dermatologists has its own registry and is looking for submissions from health care professionals.
The lesions were described as “pseudo-frostbite” by the National Union of Dermatologists-Venereologists (SNDV) (another European group), because these sometimes painful lesions popped up without cold exposure. In one interesting case in “Amici DermPed,” the child’s mother and sister had more classic symptoms of COVID-19, with fever, cough, and shortness of breath the week before the boy developed skin lesions on his feet.
A more unusual rash was noted in Bangok. There, a patient presented with a skin rash called a petechial rash (like tiny bruises) and low platelet count. These symptoms are typical for dengue fever, a common mosquito-borne viral infection there, so it was assumed that was causing the patient’s symptoms. Only later, after the patient was admitted to a tertiary medical center with breathing problems, was the COVID-19 diagnosed.
Clinicians are warned of one other masquerader. The pernio type rash, especially if there are painful pustular blisters on a reddish base, might be mistaken for community-associated MRSA (methicillin-resistant Stapylococcus aureus) lesions. It had become common understanding in practice that if a person came in complaining of a painful “spider bite,” they more likely had an MRSA infection.
Dr. Ilan Schwartz, assistant professor of infectious disease at University of Alberta, has an excellent thread on Covid toes that starts here.
Each of these rashes now seen with COVID-19 are signs of blockage or inflammation in small blood vessels. Curiously, patients with such rashes, especially children, seem to have a milder course thus far.
This seems a bit surprising to me, since we now are seeing that one common thread in more severe cases is abnormal clotting. This is why use of anticoagulants for COVID-19 patients is increasingly recommended. Yet people are developing clots even while on anticoagulants. Severe strokes in young adults was just described as yet another complication of COVID-19, though this was in otherwise healthy young adults.
Mild clotting is seen in the lungs, kidneys, heart and extremities. Broadway actor Nick Corduro had to have his leg amputated from clotting from the virus and has had quite a few complications.
We don’t understand clearly why these clots are happening. We do know that the receptor for SARS-CoV-2, the virus that causes the COVID-19 infection, is found on the lining of blood vessels (vascular endothelial cells). The receptor is called angiotensin converting enzyme 2 (ACE-2). So perhaps this is why so much heart involvement is being seen with COVID-19. In a small study from Washington state, a third of the patients developed heart involvement.
While our understanding of COVID-19 has been progressing relatively quickly, there is still so much we don’t know. This virus appears to be acting like syphilis, “the great imitator,” with so many different manifestations in people—and we don’t know why that is true. Surprisingly, the CDC just listed symptoms of coronavirus—but doesn’t list these rashes that have been popping up for weeks.
COVID can cause a wide range of symptoms in people, but we don’t know why there is such a variety. Blood vessel inflammation appears to be a common denominator. Why those with skin rashes often may have mild courses, is a great mystery.