COVID-19 is primarily a respiratory illness, but it is a systemic disease that can affect nearly every organ system. Beyond the lungs, the infection triggers widespread inflammation that significantly impacts the lower extremities. The legs and feet are common targets for the virus’s effects, manifesting through skin changes, nerve issues, and circulatory problems. This involves the dermatological, nervous, and vascular structures within the feet and legs.
Direct Skin Manifestations
One of the most recognized dermatological signs linked to the infection is “COVID toes.” These lesions resemble pernio or chilblains, but they appeared frequently in COVID-19 patients, often in warmer weather. The appearance usually involves one or more toes becoming swollen and developing a distinct discoloration, ranging from pink or bright red to a purplish hue.
These changes are believed to be a form of vasculopathy, indicating an inflammatory process within the small blood vessels of the skin. The affected areas may feel itchy, tender, or painful, and sometimes small blisters or rough skin patches form. “COVID toes” frequently occur in people with mild or asymptomatic cases, suggesting a localized immune response is responsible.
The feet and legs can also display less specific, generalized skin reactions during an active infection. These include maculopapular or morbilliform rashes, which appear as flat spots and small raised bumps, typically on the extremities. In severe cases, a lacy, net-like pattern called livedo reticularis or purpuric spots may appear, signaling serious clotting issues within the skin’s blood vessels.
Musculoskeletal and Neuropathic Symptoms
Many individuals experience significant muscle pain in their legs, known as myalgia, during the acute phase of COVID-19. This aching is one of the most common non-respiratory symptoms, sometimes appearing before typical signs like fever or cough. This widespread muscle discomfort results from the body’s overactive inflammatory response, where cytokines are released to fight the virus but also cause pain and weakness in muscle tissue.
Muscle involvement can manifest as weakness, stiffness, or fatigue that makes movement difficult, especially in the lower limbs. The virus may also directly affect muscle cells by attaching to ACE2 receptors on their surface, contributing to damage and pain. While acute myalgia typically resolves as the initial illness clears, persistent leg muscle aches are reported in some Long COVID cases.
COVID-19 is also associated with peripheral neuropathy, involving the small nerves in the feet and lower legs. Neuropathy symptoms include abnormal sensations like tingling, numbness, burning, or “pins and needles” in the feet. This nerve damage may arise from systemic inflammation or potentially from the virus directly invading peripheral nerves.
Symptoms range from mild, intermittent sensations to intense, persistent pain that interferes with daily life. In rare instances, the virus is linked to Guillain-Barré syndrome, a post-infectious process causing rapid muscle weakness and paralysis, often beginning in the lower extremities. Neuropathic symptoms can arise during the acute illness or develop weeks to months afterward as a component of Long COVID.
Vascular and Circulatory Complications
The most concerning effect of COVID-19 on the legs involves the vascular system and the increased risk of blood clotting. The infection induces hypercoagulability, meaning the blood is more prone to forming clots, which can lead to Deep Vein Thrombosis (DVT). DVT occurs when a blood clot develops in a deep vein, most commonly in the legs or thighs.
The virus initiates this process through two mechanisms: damage to the blood vessel lining and a massive inflammatory response. The virus uses the ACE2 receptor to enter cells lining the blood vessels, causing endothelial injury. This injury, combined with the immune system’s cytokine release, promotes the expression of clotting factors.
DVT symptoms are often localized and distinct, typically affecting only one leg. The affected leg may show sudden, severe swelling and a feeling of warmth, accompanied by pain or tenderness, especially in the calf or thigh. The skin over the clot may also appear red or discolored.
DVT represents a significant risk because the clot can detach and travel to the lungs, causing a life-threatening blockage called a Pulmonary Embolism (PE). Hospitalized patients, particularly those in intensive care, have a substantially higher risk of developing DVT. This risk underscores why the virus’s effects on the lower limb circulatory system are among the most serious complications.
Symptom Duration and Medical Guidance
The duration of lower extremity symptoms is highly variable. Acute symptoms like myalgia and generalized aches typically last one to two weeks during the initial illness. If muscle pain or leg fatigue persists beyond 30 days, it is classified as a symptom of Long COVID and can continue for months.
“COVID toes” generally resolve spontaneously, often lasting several weeks before discoloration and swelling disappear. Persistent peripheral neuropathy, characterized by chronic tingling or burning in the feet, can last for a prolonged period, sometimes a year or more. Treatment for persistent issues focuses on managing symptoms and reducing inflammation.
It is important to recognize specific “red flag” symptoms that require immediate medical attention, particularly those related to DVT and PE.
Red Flag Symptoms
- Sudden, severe swelling, pain, warmth, or tenderness noticeably worse in one leg, which requires urgent evaluation for a possible blood clot.
- Symptoms indicating a pulmonary embolism, such as sudden labored breathing, chest pain, or an irregular heartbeat, which require emergency care.
- Any sudden loss of sensation.
- Change in the color of the foot that suggests a lack of blood flow.