COVID-19, caused by the SARS-CoV-2 virus, is widely recognized as a respiratory illness. However, its systemic effects extend beyond the lungs, impacting various organ systems, including the legs and feet. These lower extremity manifestations can range from visible skin changes and swelling to more subtle neurological and circulatory issues.
Common Leg and Foot Manifestations
One frequently reported skin manifestation is known as “COVID toes,” resembling chilblains or pernio-like lesions. These typically present as swollen, discolored areas on one or more toes, which can appear red, purple, or even bluish-red. Affected toes may also be painful, itchy, and sometimes develop blisters or ulcers. This condition is observed more often in children, teenagers, and young adults, often appearing with mild or no other typical COVID-19 symptoms, and can persist for 10 to 14 days, occasionally longer.
Other rashes can appear on the legs and feet, including patchy rashes, itchy bumps, blisters, tiny pinpoint spots, or lace-like patterns. Skin discoloration, such as a mottled appearance (livedo reticularis) or a general purplish or bluish tinge, may also be observed. Swelling (edema) can affect the legs, ankles, and feet, often resulting from inflammation and fluid retention.
Generalized muscle aches and joint pain are common symptoms affecting the legs and feet during COVID-19. This discomfort can manifest as soreness, a deep ache, or cramping and spasms. Such pain can be experienced during the acute phase of the illness or may persist as part of long COVID.
Neurological Impacts
COVID-19 can affect the nervous system, leading to specific symptoms in the legs and feet. Peripheral neuropathy is a neurological impact, characterized by sensations such as numbness, tingling, or a “pins and needles” feeling. Patients may also experience burning sensations or unusual sensitivity to touch in their feet and hands, sometimes extending up into the legs and arms.
Muscle weakness or difficulty with movement can arise from nerve involvement. This weakness may be a direct result of the virus’s effect on nerves or a symptom of more severe neurological conditions. In some cases, COVID-19 has been associated with Guillain-Barré syndrome, a rare autoimmune disorder where the body’s immune system mistakenly attacks its own nerves.
Guillain-Barré syndrome often begins with tingling and weakness in the feet and legs, which can then spread to the upper body and arms. This progression can lead to significant muscle weakness and, in severe instances, paralysis.
Vascular Complications
COVID-19 carries a heightened risk of serious circulatory issues, particularly blood clot formation. Hospitalized patients with COVID-19 are at an increased risk of developing these clots. Deep vein thrombosis (DVT) is a common type of clot that forms in the deep veins of the legs.
Symptoms of DVT in the legs typically include swelling, pain, warmth, and tenderness, often accompanied by redness, especially behind the knee. A more severe complication occurs if a DVT breaks off and travels to the lungs, resulting in a pulmonary embolism (PE). Signs of a PE can include sudden shortness of breath, chest pain that worsens with breathing, and in severe cases, collapse.
Beyond large vessel clots, COVID-19 can lead to impaired circulation or damage to small blood vessels. This can manifest as painful or cold extremities, or distinctive skin changes.
Underlying Biological Mechanisms
The varied symptoms affecting the legs and feet in COVID-19 patients stem from several interconnected biological processes. One significant factor is the body’s immune response, which can sometimes become overly aggressive, leading to what is termed a “cytokine storm.” This excessive release of inflammatory signals can cause widespread inflammation throughout the body, contributing to muscle aches, pain, and swelling in the legs and feet.
Another mechanism involves endothelial dysfunction, which is damage to the inner lining of blood vessels. The SARS-CoV-2 virus can directly infect these endothelial cells or trigger an inflammatory response that harms them. This damage can disrupt normal blood flow, leading to localized swelling and discoloration, and affecting the proper function of small blood vessels in the extremities.
COVID-19 can induce a state of hypercoagulability, meaning the blood becomes more prone to clotting. This increased clotting tendency, combined with potential vessel damage and reduced mobility during illness, elevates the risk of forming blood clots in the deep veins of the legs. While direct viral invasion of muscle cells or nerves is being investigated, immune-mediated damage is considered a significant contributor to the pain, weakness, and neurological issues observed.
When to Seek Medical Attention
Prompt medical evaluation is important for certain leg and foot symptoms experienced during or after a COVID-19 infection. Sudden severe pain or rapid swelling in a leg or foot warrants immediate attention, as these can be indicators of a deep vein thrombosis (DVT). The presence of warmth, redness, or tenderness accompanying swelling in the leg should also prompt urgent medical consultation, as these are classic signs of a blood clot.
If leg symptoms are accompanied by difficulty breathing, chest pain that worsens with deep breaths, or coughing up blood, it could signal a pulmonary embolism, which is a life-threatening emergency. Any sudden onset of numbness, tingling, or weakness affecting an entire limb or one side of the body also requires immediate medical assessment, as this can indicate nerve damage or a serious neurological event.
If skin discoloration on the feet or toes darkens significantly, spreads rapidly, or if new blisters or open sores develop, seeking medical advice is important. For any persistent leg or foot symptoms that cause concern, worsen over time, or interfere with daily activities, consulting a healthcare professional is advisable for proper diagnosis and management.