COVID-19 is a novel type of respiratory tract infection. Like all respiratory infections, it affects the upper and also lower respiratory tract, depending on its severity. COVID-19 produces symptoms typical of respiratory infections, notably throat soreness, coughing, nose stuffiness alternating with a runny nose, but also chest tightness or pressure and breathing difficulties in more severe forms. Symptoms such as fever, fever alternating with chills, body aches, fatigue and malaise also occur, but are nonetheless typical of respiratory tract infections as a result of immune system involvement. But there are other symptoms of COVID-19 that aren’t quite typical, that is, we wouldn’t normally associate them with a respiratory infection. Read on to find out more about these 4 atypical Coronavirus symptoms and what exactly causes them.
(1) COVID toes and fingers
Dubbed COVID toes by the media, the symptom refers to a type of skin rash occurring on toes, but also fingers. The rash presents with red or purplish spots on the skin of the toes and also fingers, but there usually is no itching involved like in the case of a true rash such as urticaria or hives (although there can be since there’s still so much to learn about the novel Coronavirus). COVID toes look a lot like chilblains or chill burns, a type of tissue damage caused by excessive exposure to low temperatures and humidity. This is a relatively ‘new’ Coronavirus symptom, that is, only recently associated with COVID-19, although it is known that there are many other viral infections that cause cutaneous manifestations (e.g. chicken pox). One study on COVID-19 patients in northern Italy found the incidence of COVID toes to be as high as 20% (source: J Eur Acad Dermatol Venereol. 2020 Mar 26. See study).
What is the mechanism behind COVID toes? Experts suggest that the symptom dubbed as COVID toes is caused by instances of ischemia brought on by reduced blood flow and, subsequently, reduced oxygenation of limbs. This is believed to be a result of a Coronavirus-associated clotting problem, a newly discovered complication arising from the COVID-19 infection. However, the tissue damage resulting in the rash known as COVID toes is not permanent and should resolve itself over the course of days or weeks. Nevertheless, if the disease progresses to severe forms, the symptom should be brought to the attention of medical personnel, even if resolved by that time, as it can indicate an underlying blood clotting issue with the potential for fatal complications (e.g. pulmonary embolisms). Complications arising from blood clotting issues brought on by the novel Coronavirus infection can be successfully treated with anticoagulants.
(2) Non-specific rashes
It’s highly unusual to get rashes on the body when you have a viral respiratory infection. Or so you’d think. However, many viral infections produce cutaneous manifestations, whether it’s chicken pox, rubella, measles or rubeola, the common cold or COVID-19. Coronavirus-related skin rashes can vary immensely in appearance and mimic other conditions. While they can occur almost anywhere on the body, the torso, extremities and even face have been reported to be the most likely areas affected. It is believed that immune system implication as a result of a systemic infection, affecting more than just the respiratory system, is the most likely cause for COVID-19 rashes.
Symptoms of Coronavirus rashes may include the following:
- Covid toes and fingers: chilblain-like presentation
- Petechiae-like rash: tiny, round, pinpoint-like red, purple or brown spots on the skin (source)
- Livedoid rashes: patches of bluish skin discoloration due to deoxygenated or insufficiently oxygenated blood supplying capillaries
- Erythematous rash: patches of red, inflamed or irritated skin
- Hives or urticaria-like rash (observed to be of low incidence)
- Chicken pox or varicella-like rash: small, red dots, bumps or blisters on the skin (reported to be of low incidence)
The true incidence of cutaneous manifestations of the novel Coronavirus infection is largely unknown and existing data is based mostly on local reports. Reports which do not account for undiagnosed cases, cases of sub-clinically symptomatic individuals (those with not enough symptoms or symptoms not serious or evident enough to be diagnosed with the novel Coronavirus) and other otherwise relevant factors that would have provided a more factual representation of the prevalence of COVID-19 cutaneous symptoms, aka rashes.
(3) Loss of smell
Anosmia, or loss of smell, is one of the most recently confirmed symptoms of COVID-19. From data collected up to this point, loss of smell is not that uncommon of a symptom of COVID-19 as one would think. Approximately 2 out of 3 or 30% of confirmed Coronavirus cases experienced some degree of loss of smell, based on data from South Korea, China, Germany and Italy. See source. Affected individuals report partial to total loss of smell lasting from under a week to up to 3 weeks or more. According to reports, Coronavirus-associated loss of smell appears early in the infection and can be considered one of the earliest signs of COVID-19. In addition to this, it is often also one of the few symptoms present in mild forms of the disease, if not the only one. See the complete list of COVID-19 symptoms.
The loss of smell can be explained by, first, inflammation produced at the level of the nasal passages. It is known that the nose is one of the most common points of entry of 2019-nCov or SARS-CoV-2, aka the novel Coronavirus. Cells in the nose are also filled with ACE2 receptors to which the virus attaches, meaning the novel Coronavirus does produce infection at the level of the nose in incipient stages. This results in inflammation that can lead to loss of smell. Moreover, as the immune system activates, inflammatory cytokines are produced as part of the immune system response, adding to the inflammation and contributing to the symptom.
Of all the atypical symptoms of COVID-19, loss of smell is likely the most disputed. Anosmia has been generously documented in scientific literature and some of the most likely triggers for it are respiratory infections, particularly respiratory infections of viral origin such as the common cold or COVID-19. Interestingly enough, the common cold, which is a viral respiratory infection just like COVID-19, largely caused by rhinoviruses (up to 80%) and coronaviruses other than the novel Coronavirus (up to 15%), also presents with loss of smell as a defining symptom. For this reason, a lot of people refuse to accept anosmia as an early symptom indicative of COVID-19, attributing it to the common cold or other more common respiratory infections. Their reasoning is largely based on the fact that COVID-19 is a serious disease, whereas the common cold isn’t, so if the symptoms aren’t severe, it can’t be COVID.
Add the fact that the current pandemic overlaps with the spring season and related seasonal allergies, whose more defining symptoms are a runny nose, nasal congestion, red, watery, itchy eyes and loss of taste and smell, unless tested and confirmed with COVID-19, people with mild symptoms such as a headache or some degree of loss of smell might go undiagnosed. Also see the Difference between Allergy, Cold, Flu, Sinus Infection.
(4) Loss of taste
If you’ve experienced a sudden loss of taste sometime in the past few months, or just haven’t been able to taste much of anything at one point or another during the current pandemic, there are a few causes you can consider, including the common cold, the flu, sinusitis, pharyngitis or a sore throat, seasonal allergies and the novel Coronavirus infection. In the initial stages, the Coronavirus infection is limited to the upper respiratory tract which includes the nose and throat. It stands to reason that the mouth and taste perception can also be affected since they’re right where the action is.
While one of the symptoms considered atypical for Coronavirus, loss of taste is actually not as unusual as one would think. For one, taste perception is affected by the ability to smell which basically means we can taste (things) better if we are also able to smell well. If the olfactory senses are impacted by the Coronavirus infection, and they are, there will also be a reduced ability to taste.
A likely explanation for the loss of taste with COVID-19 is the virus’ nervous system involvement. More exactly, the novel Coronavirus, 2019-nCov or SARS-CoV-2, produces infection by biding to cells that have an ACE2 receptor (the angiotensin-converting enzyme 2). ACE2 receptors are found throughout the brain tissue and allow the virus to enter the nervous system. By producing infection in nerve cells of the cerebral cortex which are responsible, among other things, for perception (taste, smell, sight, sound, touch etc.), the novel Coronavirus impacts our ability to taste. Infected cells no longer respond to stimuli correctly and the gustatory perception is impacted. This results in lowered ability to taste, distortions of taste perception and even complete lack of taste. However, the loss of taste due to COVID-19 is temporary. The unusual or atypical symptom is actually considered by some to be a sign of mild disease and has been reported in mild forms of COVID-19 along with loss of smell.
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