Can you tell if you have COVID-19 by looking at your toes?

By Shilacshan Lingakumar

When one is infected with COVID-19, there are many symptoms that are present such as a cough, shortness of breath, a fever and sneezing. COVID-19 can also show symptoms on the skin in some cases, particularly on one’s toes which is informally called “COVID toes”.

According to the American Academy of Dermatology Association, some patients who test positive for the coronavirus develop discoloured and swollen toes. There appears to be no restriction regarding the age group and these symptoms are present with others, such as a cough but they tend to be mild. Along with the swelling and discoloration, COVID toes can also include blisters, itching or pain and some people develop painful raised bumps or areas of rough skin or see a small amount of pus. It looks similar to chilblains which are small, itchy, red patches that can appear after you have been in the cold.

In July 2020, an asymptomatic doctor, had endured a two-week period of a burning itch of her fingers and toes with erythema (abnormal redness) and purple papules. Erosions were present on her fingers, and nail fold telangiectasia (visible blood vessels on skin) was seen. 

It is postulated that the mechanism could be direct endothelial damage inflicted by the virus or a link to endothelial dysfunction from the increased number of thrombotic events in COVID-19 patients due to increased thrombin generation that inhibits fibrinolysis – blood clots caused by the virus and immune response. The second BMJ article is a case report, details a case of COVID toes in late April 2020. She was prescribed gabapentin and codeine (30 mg) with acetaminophen (300 mg) to alleviate the pain but that was not successful. After these medications failed, the patient was started on ropinirole, which provided almost complete relief of the muscle symptoms. The patient did have a history of antiphospholipid syndrome (APS), which is an autoimmune disorder which occurs when your body's immune system makes antibodies that attack phospholipids – blood clots are one of the symptoms of APS. But this is fairly unique and many other sufferers of COVID toes do not have APS, so in this woman’s case, APS may have merely worsened the symptoms. 

Another potential mechanism suggested is the cytokine production which is part of a normal immune response. Joseph Roche, an associate professor in the physical therapy program at Wayne State University, hypothesises that an accumulation of two peptides, des-Arg(9)-bradykinin, abbreviated to DABK, and bradykinin was causing this. Early evidence also suggests that COVID Toes may be part of a wider range of skin rashes formed due to COVID-19 and may be a characteristic for Post-Acute COVID-19 symptoms. (also known as Long COVID)

Much is unknown about COVID toes and other “weird” symptoms of COVID-19 – scientists are still learning. 

References and further reading:

https://www.aad.org/public/diseases/coronavirus/covid-toes

https://www.bmj.com/content/370/bmj.m2245

https://www.nhs.uk/conditions/chilblains/

https://rarediseases.info.nih.gov/diseases/5824/antiphospholipid

https://www.bmj.com/content/370/bmj.m3026

https://www.vox.com/21445038/covid-19-symptoms-treatments-bradykinin-cytokine-storm

https://www.nytimes.com/2020/05/01/health/coronavirus-covid-toe.html