When the COVID-19 pandemic swept across the globe in early 2020, healthcare providers and researchers scrambled to understand the myriad ways SARS-CoV-2 could affect the human body. While respiratory symptoms dominated early clinical descriptions, a peculiar dermatological manifestation soon captured medical attention: “COVID toes,” or as it became known in medical literature, pernio-like lesions associated with COVID-19 infection.
COVID toes emerged as one of the pandemic’s more puzzling symptoms, appearing primarily in children, adolescents, and young adults who otherwise experienced mild or even asymptomatic infections. The condition presented as red or purple lesions on the toes, and less commonly on the fingers, resembling chilblains or pernio—a inflammatory condition typically triggered by exposure to cold and damp conditions. However, these lesions appeared in patients regardless of climate or season, suggesting a different underlying mechanism.
The lesions themselves varied in appearance but shared common characteristics. Patients typically developed discolored patches ranging from pink to dark purple, often accompanied by swelling, tenderness, and itching or burning sensations. Some cases presented with small blisters or pustules. Unlike traditional chilblains, which affect individuals exposed to cold weather, COVID toes appeared year-round and in warm climates, immediately distinguishing them from their cold-weather counterpart. The lesions most commonly affected the dorsal surface of the toes, though they could appear on any digit or even the heels.
What made COVID toes particularly intriguing was their demographic distribution. While COVID-19 generally posed greater risks to older adults and those with comorbidities, this dermatological manifestation predominantly affected younger, healthier individuals. Many patients with COVID toes had no other symptoms of COVID-19, or their respiratory symptoms were minimal. This raised important questions about the body’s immune response to SARS-CoV-2 and why certain individuals developed these unusual skin manifestations while others did not.
The timeline of COVID toes also proved distinctive. Unlike many COVID-19 symptoms that appeared early in infection, these lesions often emerged later in the disease course or even after other symptoms had resolved. In some cases, they appeared weeks after initial infection, making it challenging to establish a definitive causal relationship. This delayed presentation suggested the lesions might result from the body’s immune response rather than direct viral damage to tissue.
Researchers proposed several mechanisms to explain COVID toes. The leading hypothesis centered on the immune system’s response to viral infection. The body’s interferon response—a crucial first-line defense against viruses—appeared particularly robust in younger individuals with COVID toes. This strong interferon response might trigger inflammation in small blood vessels, particularly in the extremities, leading to the characteristic lesions. Microscopic examination of affected tissue revealed inflammatory changes in blood vessel walls and signs of clotting in small vessels, supporting this vascular inflammation theory.
Another proposed mechanism involved the formation of microclots in small blood vessels of the toes. SARS-CoV-2 infection is known to increase clotting risk throughout the body, and this hypercoagulable state might manifest in the tiny vessels of the digits, causing reduced blood flow and tissue damage. The purple or blue coloration of some lesions supported this hypothesis, as it suggested compromised circulation.
Diagnosis of COVID toes presented challenges. While the clinical appearance was often distinctive, confirming a connection to COVID-19 proved difficult. Many patients with COVID toes tested negative for active infection via PCR testing, likely because the lesions appeared after the acute infection had cleared. Antibody testing sometimes helped establish prior infection, but in the pandemic’s early days, testing limitations and the timeline of antibody development complicated matters. Dermatologists and infectious disease specialists had to rely on clinical presentation, patient history, and exclusion of other causes.
Treatment approaches varied, reflecting the uncertainty about underlying mechanisms. Most cases resolved spontaneously within weeks, requiring only supportive care and symptom management. Clinicians recommended keeping the affected areas warm, elevating the feet, and avoiding tight footwear. For more symptomatic cases, topical corticosteroids helped reduce inflammation and itching. Some severe cases warranted oral medications, including corticosteroids or vasodilators to improve circulation. The self-limiting nature of most cases meant aggressive intervention was rarely necessary.
The prognosis for COVID toes generally proved excellent. While the lesions could be painful and concerning, they typically resolved completely without permanent damage. Most patients recovered within two to eight weeks, though some cases persisted longer. Scarring was uncommon, and recurrence appeared rare. This benign course provided some reassurance to affected patients and their families.
COVID toes also highlighted the importance of recognizing diverse COVID-19 manifestations. Early in the pandemic, narrow case definitions focusing solely on respiratory symptoms may have led to underrecognition of infections, particularly in younger individuals with atypical presentations. The identification of COVID toes and other dermatological findings expanded understanding of how SARS-CoV-2 affects different body systems and different age groups.
As the pandemic evolved through various waves and viral variants, the prevalence of COVID toes appeared to decrease, though reports continued. Whether this reflected changing viral characteristics, increased population immunity, or improved recognition and reporting of other symptoms remains unclear. Researchers continue studying these lesions to better understand immune responses to COVID-19 and why certain individuals develop particular manifestations.
COVID toes ultimately represents more than just an unusual symptom—it exemplifies the complexity of viral infections and host immune responses. This distinctive manifestation taught clinicians to maintain broad differential diagnoses, reminded researchers of the importance of studying diverse disease presentations, and demonstrated how a novel pathogen can surprise us with unexpected clinical features. As we continue to live with COVID-19, understanding all its potential manifestations, including COVID toes, remains crucial for comprehensive patient care.