Skin can become blue or purple due to bruising, but this color change can also indicate that not enough oxygen-rich blood is reaching the area. The feet are particularly prone to discoloration as they are further away from the heart.
Temporary changes in skin color can be harmless, but persistent or reoccurring discoloration in the feet might signify a health problem.
In this article, we look at some of the possible causes of purple feet and how to treat them.
Foot injuries can cause purple bruises.
Sprains, strains, or dropping something onto the foot can cause bruising, which tends to make the skin appear blue or purple. Such an injury will also often cause pain and swelling. People can usually treat minor foot injuries at home using RICE therapy:
- Rest. Avoid doing unnecessary activities and placing weight on the injured foot for prolonged periods.
- Ice. Apply an ice pack to the injured foot.
- Compression. Wrap the injured foot in a bandage. The bandage should fit snugly but not be tight enough to prevent blood circulation.
- Elevation. Use pillows or a footstool to raise the foot whenever possible.
Over-the-counter nonsteroidal anti-inflammatory medications, such as ibuprofen or aspirin, can help reduce pain and swelling.
For more severe injuries, a doctor may order an X-ray to check for broken bones in the foot. Treatment for a broken foot depends on the type and severity of the fracture.
Raynaud's disease, also known as Raynaud's phenomenon, is a common condition that can cause the blood vessels in the hands or feet to temporarily spasm and constrict. This behavior blocks the flow of blood, which can lead to the affected areas turning blue, purple, red, or white.
Attacks of Raynaud's disease can also cause symptoms that include pain, numbness, and pins and needles. These attacks can make it difficult for a person to use their feet or fingers.
Most cases of Raynaud's are mild. Keeping the feet and hands warm and dry during cold weather and minimizing stress can help prevent attacks. For people with more severe Raynaud's, a doctor may prescribe medication to help control symptoms.
Vasculitis can cause a rash that appears red or purple.
Lupus, or systemic lupus erythematosus, is an autoimmune condition, which means that the body's immune system mistakenly attacks healthy tissues and organs. Symptoms of lupus vary considerably in type and severity, and they can affect many different areas of the body, including the feet.
Lupus can lead to vasculitis, which is inflammation of the blood vessels. When vasculitis occurs in the feet, it can cause a rash in the form of red or purple dots on the skin. This rash can appear on other parts of the body too. Vasculitis may also cause numbness, tingling, and loss of strength in the foot.
Anyone with symptoms of lupus should see a doctor. Treatment of lupus depends on the symptoms. Mild vasculitis that only affects a person's skin will typically require less extensive treatment than lupus that affects multiple body regions.
Peripheral artery disease
Peripheral artery disease (PAD) is a narrowing of the arteries outside the core of the body. It restricts blood flow to some of the outer parts of the body, including the limbs.
PAD often affects the legs, and people may experience symptoms that include pain, cramping, tingling, and weakness. The reduced blood flow can also cause the legs and feet to turn blue or purple gradually. However, some people with PAD may not have any symptoms.
Anyone with symptoms of PAD should see a doctor. Without treatment, the condition can progress and lead to serious complications, such as severe ischemia and gangrene.
Lifestyle changes, medications, and surgical interventions can slow or halt the progression of the condition and reduce the risk of complications. Beneficial lifestyle measures include doing regular exercise, avoiding tobacco smoking, and eating a healthful diet.
Diabetes is a condition that affects the regulation of blood sugar levels. Too much sugar in the blood can lead to a range of symptoms, including foot problems that result from damage to the peripheral blood vessels and nerves. People with diabetes also have a high risk of developing PAD.
Uncontrolled blood sugar levels can cause the blood vessels in the legs and feet to become narrow and stiff. The resulting reduction in blood flow to the feet can lead to:
- purple or blue coloring
- cold feet
- nerve damage
- pain and cramping
- pins and needles
- slow healing of cuts and wounds
Nerve damage can also make it difficult for a person to feel cuts and other injuries on the feet.
People with diabetes can reduce or prevent foot problems by:
- regularly checking the feet for cuts, sores, injuries, and other issues
- keeping blood sugar levels under control through lifestyle changes and medications
- eating a heart-healthy diet to control cholesterol
- lowering blood pressure if necessary
- not smoking
- exercising regularly
Severe frostbite can cause permanent tissue damage.
Frostbite is damage to the skin and tissues that results from exposure to freezing temperatures. The body's extremities, such as the hands and feet, are especially prone to frostbite.
Signs of frostbite can include:
- discoloration of the skin, which may be gray, blue, or purple
- pins and needles
- skin that feels unusually hard or resembles wax in appearance
Frostbite can permanently damage the body's tissues. In extreme cases, a doctor may need to amputate the affected part of the body.
To avoid frostbite:
- Dress warmly and in layers when going outside in the cold. Wear warm socks and water-resistant boots and cover all exposed skin when it is extremely cold.
- During the cold months, avoid going outside if local weather authorities issue frostbite warnings.
- Avoid getting the hands or feet wet when out in the cold. If they do get wet, go inside and dry the skin.
- Check the skin every so often for signs of pain, discoloration, or numbness. Monitor children's skin and ensure that they are staying warm and dry when playing outside in the cold.
People with conditions that affect blood circulation have a higher risk of frostbite. Risk factors include:
- Raynaud's disease
- previous frostbite
Anyone who has signs or symptoms of frostbite after being out in the cold should seek immediate medical attention.
There are many possible causes of purple feet. Skin discoloration can result from bruising following a minor injury. However, purple or blue skin can also indicate a restriction of blood flow to the feet, and this can be a symptom of an underlying health condition.
Conditions that can affect blood circulation in the feet include Raynaud's disease, PAD, lupus, diabetes, and frostbite. Anyone who experiences persistent or reoccurring discoloration of the feet should see a doctor.
People with chronic conditions that can affect blood circulation should go for regular medical checkups and follow their doctor's advice for managing their symptoms.