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The most common causes of what looks like a rash or red dots on the lower legs are either immune-mediated inflammation like eczema or psoriasis, or a skin infection like cellulitis. Other causes of red blotches on the lower legs can arise from an allergic reaction to certain foods or contact with poisonous plants. Read below for more information on on other causes, related symptoms like swollen ankles or scaly skin on lower legs, and treatment options.
Lower leg redness symptoms explained
Lower leg redness can be caused by a host of conditions, both benign and more concerning. One of the most common and serious is cellulitis, an infection of the skin. Veins that cannot carry blood back to the heart can cause a backup and blockage of the arteries of the leg can also cause pain in the leg. Finally, a simple and very common rash like psoriasis or eczema can also cause redness in the lower legs.
Common characteristics lower leg redness
Associated characteristics of lower leg redness may include the following.
- Dry, scaly, flaky, or leathery skin that may be intensely itchy
- Skin plaques: Large, red, scaly patches of skin that persist.
- Pain or swelling of the leg or legs
- Warmth of the area
- A visible bump or bumps
- Abscess: A pus- or fluid-filled bump in the skin indicating an infection.
What causes redness in lower legs?
Causes of lower leg redness can be categorized as infectious, due to blood vessels or blood flow, and various forms of inflammation.
Infections of the skin or the blood vessels of the leg are serious because it can track from the skin into the blood or muscle and lead to shock or infection of the fascia which can cause amputation or death.
- Cellulitis: This can cause an area of inflammation because of the entry of bacteria into the skin. It is one of the most common causes of skin infection. Usually, cellulitis affects older adults and can occur in individuals with no underlying conditions. Abscesses typically occur when the skin barrier is disrupted due to trauma, skin inflammation (e.g. psoriasis or eczema) or swelling due to lymphedema or venous backup. Most cases of cellulitis are caused by streptococcus a type of bacterium that lives on the skin though cellulitis can be caused by animal bites, plant thorns, and bacteria that live in the mouth or the nose, in the case of a bite. Cases are almost universally treated with antibiotics when they come to medical attention.
- Suppurative thrombophlebitis: This refers to an infected blood clot in the veins of the lower extremities. When the vein is superficial, treatment is optional, but when the clot is in a deep vein (deep vein thrombosis or DVT), treatment is necessary to cause the clot to dissipate, to prevent recurrence, and to the prevent the clot traveling to the lungs and causing a pulmonary embolism (PE). Without either extraction or dissolution of the clot, the infection will not disappear. Because it is already in a vein, it will continuous allow small flecks of bacteria into the venous system which may travel through the blood and cause serious illness.
- Skin abscess: This is a collection of pus within the skin or just beneath the skin which can cause overlying redness and even feed infection of the skin causing a cellulitis. Generally, the treatment for an abscess is through an incision and drainage procedure, where the area is then packed with material that will keep it from closing and allow it to heal from the bottom of the wound outward.
The backup of blood into the legs can cause redness as blood pools in the lower extremities. There are many causes of backup and the most common and one of the most dangerous is covered below.
- Venous stasis dermatitis: This is a common cause of inflammation of the skin and occurs in individuals who have "chronic venous insufficiency" or veins that are unable to help blood move upward toward the heart. Generally, venous statous dermatitis causes red, scaly, dry patches across the leg. Often swelling and redness are most severe at the ankle. The rash is not often itchy, but when it is scratched, it can cause inflammation of the lower leg. Over time the leg may darken as a chemical in the blood begins to stain surrounding tissues. Occasionally, inflammation of the fat can occur and this can cause pain in both legs. Venous stasis is managed frequently through compression, walking, and in rare cases, by drugs that help make the vein less flaccid (e.g. phlebotonic drugs).
- Compartment syndrome: Like any disorder that blocks blood flow, the structure of the foot can cause inflammation as the cells that are deprived of oxygen struggle to survive with decreased blood flow. This is generally a very quick process and the only treatment is to restore blood flow to the lower leg as well as oxygen. This is done by decompressing the leg with a fasciotomy, in which the leg is opened to allow swollen tissue to swell outward instead of inward. When the tissue has stopped swelling, the leg is reclosed. This is a medical emergency needing immediate attention.
Rashes are common and can affect the legs. Not every cause of redness in the lower legs is life- or limb-threatening. It is possible to have redness from common rashes that may affect the arms, back, or belly as well.
- Eczema: This is also known as atopic dermatitis and refers to a long-term, itchy, and red skin disorder. It commonly affects children but can also affect adults. In adults, eczema is usually localized to the areas of the body that flex and tends to result in thickened and very itchy skin. Skin affected by eczema may also be reactive and turn red with minimal irritation or contact. Eczema may cause red bumps either on its own or because of scratching caused by intense itchiness.
- Psoriasis: This most commonly causes plaques or very large scales across the body. They may appear on the knees or backside but can also occur on the legs. Often these red areas are very distinct margins and may be reddened in people with lighter pigment and darkened in people with darker pigment. In some rare types of psoriasis (e.g. erythrodermic psoriasis) redness and scaling may be present throughout the body from head to toe.
This list does not constitute medical advice and may not accurately represent what you have.
Irritant contact dermatitis
Irritant contact dermatitis means a skin reaction that is caused by directly touching an irritating substance, and not by an infectious agent such as a bacteria or virus.
Common causes are soap, bleach, cleaning agents, chemicals, and even water. Almost any substance can cause it with prolonged exposure. Contact dermatitis is not contagious.
Anyone who works with an irritating substance can contract the condition. Mechanics, beauticians, housekeepers, restaurant workers, and health care providers are all susceptible.
Symptoms include skin that feels swollen, stiff, and dry, and becomes cracked and blistered with painful open sores.
A medical provider can give the best advice on how to heal the skin and avoid further irritation. Self-treatment can make the problem worse if the wrong creams or ointments are used.
Diagnosis is made through patient history, to find out what substances the patient comes into contact with, and through physical examination of the damaged skin.
Treatment involves avoiding the irritating substance if possible. Otherwise, the person can use petroleum jelly on the hands underneath cotton and then rubber gloves.
Top Symptoms: rash with well-defined border, itchy rash, red or pink, rough patch of skin, painful rash, red rash
Symptoms that always occur with irritant contact dermatitis: rash with well-defined border
Symptoms that never occur with irritant contact dermatitis: fever, black-colored skin changes, brown-colored skin changes, blue-colored skin changes
Allergic contact dermatitis of the lower leg
Allergic contact dermatitis is a condition in which the skin becomes irritated and inflamed following physical contact with an allergen. Common products known to cause allergic dermatitis include plants, metals, soap, fragrance, and cosmetics.
Top Symptoms: lower leg redness, lower leg itch, scabbed area of the lower leg
Symptoms that always occur with allergic contact dermatitis of the lower leg: lower leg redness
Cellulitis is a bacterial infection of the deep layers of the skin. It can appear anywhere on the body but is most common on the feet, lower legs, and face.
The condition can develop if Staphylococcus bacteria enter broken skin through a cut, scrape, or existing skin infection such as impetigo or eczema.
Most susceptible are those with a weakened immune system, as from corticosteroids or chemotherapy, or with impaired circulation from diabetes or any vascular disease.
Symptoms arise somewhat gradually and include sore, reddened skin.
If not treated, the infection can become severe, form pus, and destroy the tissue around it. In rare cases, the infection can cause blood poisoning or meningitis.
Symptom of severe pain, fever, cold sweats, and fast heartbeat should be seen immediately by a medical provider.
Diagnosis is made through physical examination.
Treatment consists of antibiotics, keeping the wound clean, and sometimes surgery to remove any dead tissue. Cellulitis often recurs, so it is important to treat any underlying conditions and improve the immune system with rest and good nutrition.
Top Symptoms: fever, chills, facial redness, swollen face, face pain
Symptoms that always occur with cellulitis: facial redness, area of skin redness
Urgency: Primary care doctor
Squamous cell carcinoma
Squamous cells are the small, flat skin cells in the outer layer of the skin. Squamous cell carcinoma (SCC) a type of skin cancer that usually appears as a tiny, painless bump or patch. The most common spots for this cancer are the head (including scalp, lips, ears, and mouth), legs, and the backs of the hands and the arms.
Top Symptoms: worsening face redness, rough skin on the face, scabbed area of the face
Urgency: Primary care doctor
Solar (actinic) keratosis
Actinic keratosis, also known as solar keratosis, is the most common skin condition caused by sun damage over many years. It appears as small, rough, raised growths that may be hard and warty.
Top Symptoms: unchanged face redness, rough skin on the face, thickened skin with a well-defined border
Urgency: Primary care doctor
Allergic reaction to poison ivy/oak/sumac
Plants of the Toxicodendron genus are found throughout the continental United States, and exposure to these plants is a leading cause of contact dermititis, a medical term used to describe irritation and itching of the skin.
Top Symptoms: rash, itchy rash, red rash, skin changes on arm, stinging or burning rash
Symptoms that always occur with allergic reaction to poison ivy/oak/sumac: itchy rash, rash
Symptoms that never occur with allergic reaction to poison ivy/oak/sumac: fever
Treatments for red and swollen lower legs
When to see a doctor for lower leg redness
Treatment depends on the cause of redness. Blocked vessels should be unclogged, pooling blood should be moved, rashes should be treated, and infections should be cured. Some details are covered below; however, seeing a medical professional may be necessary for proper treatment.
- Dissolving a clot: If you suspect that your redness is caused by a clot that is infected, you will likely need treatment to treat or dissolve the clot and to treat the underlying infection. To begin these medications, you may need to be admitted to the hospital.
- Compression clothing: If you suspect that your redness is caused by chronic pooling of blood in the lower extremities, clothes that compress the legs (e.g. compression socks) are essential tools to channel blood up and out of the vasculature and back toward the heart. They can both prevent swelling and decrease already chronic swelling.
- Rash treatment: Rashes like eczema or psoriasis are frequently treated with steroid creams, by altering the diet or your exposure to allergens, or even anti-itch medications if redness is produced by scratching.
- Antibiotics: Cellulitis and other rashes caused by infection must be treated with appropriate antibiotics that are sufficient to eliminate the causative bacteria.
When lower leg redness is an emergency
You should seek help without delay if:
- You lose feeling in your lower legs
- You feel intense pain in your legs
- You feel short of breath, feel chest pain, or feel as though you might lose consciousness
- Your leg swelling does not improve over time
- Your leg feels colder than its partner
FAQs about lower leg redness
How does lower leg redness develop?
Lower leg redness is usually caused by inflammation, specifically dilation of blood vessels in the lower leg after some sort of damage to the leg. Damage is a broad term, but anything that causes the body to begin an inflammatory process or anything that causes the body to send extra blood cells to an area can cause lower leg redness. Additionally, redness can also be caused if the body is unable to remove fluid from a limb because of damage to the vessels that carry fluid or damage to the pump (e.g. heart) that moves fluid.
What are common causes of lower leg redness?
Lower leg redness is usually caused by inflammation of the skin along the lower leg. Inflammation of the skin can be caused by injury to the skin via infection or a lack of blood outflow from the leg. Damage to lymph nodes, non-healing wounds or ulcers, blood clots, or arterial blockage are all important mechanisms that may cause lower leg redness. Each of these mechanisms can cause blood or lymph to build up in the leg, and when that fluid is unable to drain, this can predispose you to infection.
How can I prevent the most common causes of lower leg redness?
The most common causes of lower leg redness are likely mild trauma, sunburn, or mild infection. Preventing mild trauma can be done by wearing clothing that covers the legs and being careful to not over-exert yourself while exercising. Stretching beforehand and making yourself aware of the potential causes of injury may also prevent mild trauma. Sunscreen, appropriate clothing, and a conservative effort to stay out of the sun can prevent sunburn. Mild infections can be prevented by wearing proper clothing to prevent scratches and bruises.
What signs suggest that lower leg redness is dangerous or life-threatening?
Lower leg redness on a single leg and a change in temperature (e.g. warmer or cooler than the opposing leg), a loss of sensation, swelling, loss of motion, or a loss of pulse are all signs that you may have a condition that requires emergency care. You may need a physician to assess for subtle signs of pulselessness or swelling in the lower leg that may be signs of a limb-threatening or life-threatening condition.
How long does lower leg redness usually last?
Lower leg redness is commonly caused by infection, and in mild cases, if the body is able to clear the infection, it can do so in two weeks or less. Stubborn infections may last longer and need medical treatment. Other medical conditions can also contribute significantly to lower leg redness, including clots blocking blood flow and damage to arterial circulation.
Questions your doctor may ask about lower leg redness
- Is the red area flaky and rough to the touch?
- Any fever today or during the last week?
- Did your symptoms start after you were exposed to nickel (commonly found in jean snaps, metal pens, paper clips, cigarettes, etc.)?
- Did you possibly brush into poison ivy, poison oak, or poison sumac?
Self-diagnose with our free Buoy Assistant if you answer yes on any of these questions.
Ezekiel Richardson is a fourth-year medical student at UPenn, currently applying into Emergency Medicine. He completed an undergraduate degree with a concentration in health disparities at Stanford University. After graduation, he spent a year working in the Maryland Department of Health as a John Gardner Public Service Fellow. Between his third and fourth year of medical school, he completed multiple publications on public health and health accessibility through the Center for Emergency Care and Policy Research Fellowship. He has participated as a teaching assistant in anatomy, histology, and doctoring ethics courses at UPenn. Outside of medical school, he enjoys cooking, volunteering, and traveling in support of his partner’s work on girls’ education in Africa.
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