What is a leg rash?
A leg rash is an inflammatory reaction of the skin on the legs that may extend to the feet. Leg rashes can be caused by a wide variety of mild to serious diseases, disorders and conditions. Leg rashes can affect a small to large area of one or both legs and can occur in all age groups and populations.
Leg rashes vary greatly in appearance, extent and severity depending on the underlying cause. Leg rashes may or may not be itchy and can be red, white, purple or silver in color. The texture of a leg rash can be flat, raised, bumpy or scaly and include flaking off or peeling of skin cells. Leg rashes can also appear as dots or spots or occur over a large, solid continuous area.
A leg rash can be a sign of a relatively minor condition, such as irritant contact dermatitis caused by exposure to an irritating substance. A rash on the legs can also be caused by an allergic reaction to a variety of allergens (allergic contact dermatitis).
Other causes of leg rashes include viral infections, autoimmune disorders, and varicose veins. Leg and foot rashes are also a complication of poorly managed diabetes and peripheral artery disease, which can cause skin changes due to poor blood flow to the extremities.
Leg rashes can have several serious causes. A rash of purple spots on the legs or other areas can indicate a potentially serious condition, such as allergic purpura. Any rash that is associated with allergies combined with shortness of breath, wheezing, or swelling of the face, mouth or throat is a symptom of a serious, potentially life-threatening allergic reaction called anaphylaxis. Seek immediate medical care (call 911) if you, or someone you are with, have any of these symptoms.
Seek prompt medical care if you do not have life-threatening symptoms but your leg rash is getting worse, does not improve within a few days, or you develop other symptoms.
What other symptoms might occur with a leg rash?
A leg rash can occur by itself or with other symptoms that affect the skin and possibly other areas of the body. Symptoms vary depending on the underlying disease, disorder or condition. For example, you may have flu-like symptoms if the leg rash is due to infection or inflammation. Some coexisting symptoms, such as anxiety and irritability, may be due to the underlying condition, or they may be caused by constant itching of the leg rash.
Skin symptoms that may occur with a leg rash
A leg rash may occur with other skin-related symptoms including:
Bleeding (from broken skin)
Blistering and possibly oozing of discharge from the rash or surrounding skin
Burning or pain
Change in skin texture
Redness, irritation or inflammation
Scaling, flaking or peeling skin
Skin that is unusually cold to the touch, possibly a sign of peripheral artery disease
Swelling or puffiness around the rash
Other symptoms that may occur with a leg rash
In some cases, a leg rash may occur with symptoms that are related to other areas of the body including:
Irritability in infants and children
Joint pain or achiness and swelling
Numbness or burning in the lower legs and feet
Stress, anxiety or depression
Symptoms of poor blood flow to the extremities (sores that do not heal, cold extremities, and muscle cramping)
Serious symptoms that might indicate a life-threatening condition
In some cases, a leg rash may occur with other symptoms that might indicate a serious or life-threatening condition that should be immediately evaluated in an emergency setting. Seek immediate medical care (call 911) if you, or someone you are with, have any of these life-threatening symptoms including:
Bloody stools or urine that is bloody, red or pink
Chest pain, pressure or tightness
Difficulty breathing, wheezing, or shortness of breath
Fainting or change in level of consciousness
High fever (higher than 101 degrees Fahrenheit)
Severe headache or abdominal pain
Sudden swelling of the mouth, lips, tongue, face, or throat
What causes a leg rash?
Leg rashes can be caused by a wide variety of diseases and conditions, such as infection, inflammation, allergic reaction, parasite and insect bites, and autoimmune processes. For example, an acute leg rash that appears suddenly may be caused by an allergic reaction or sensitivity to a particular substance, such as poison ivy, hair waxing or shaving, or an insect bite.
Serious causes of leg rashes include a severe allergic reaction with anaphylaxis (tightening and closing of the airways) and cellulitis (an invasive bacterial or fungal infection of the skin and surrounding tissues).
Infectious causes of a leg rash
A leg rash may be caused by an infection including:
Bacterial infection, such as from streptococcal and staphylococcal bacteria
Chickenpox (viral infection)
Folliculitis (infection or inflammation of a hair follicle)
Measles (viral infection)
Rocky Mountain spotted fever
Viral infections such as roseola
Allergic causes of a leg rash
A leg rash may be caused by an allergic reaction including:
Eczema (atopic dermatitis), including chronic eczema
Irritant contact dermatitis, such as poison ivy, poison oak, or poison sumac
Autoimmune and inflammatory causes of a leg rash
A leg rash may be caused by autoimmune and inflammatory disorders including:
Cutaneous lupus (autoimmune disease that affects the skin)
Discoid eczema (often due to dry skin)
Erythema nodosum (inflammatory disorder)
Vasculitis (inflammation of blood vessels)
Parasite or insect causes of a leg rash
A leg rash may be caused by parasites or insects including:
Fleas or ticks (ticks carry the bacteria that cause Rocky Mountain spotted fever)
Mites (parasites that cause scabies)
Mosquitoes (mosquitoes also carry parasitic diseases)
Other causes of a leg rash
A leg rash may also accompany the following conditions:
Anxiety and stress
Heat (heat rash)
Life-threatening causes of a leg rash
In some cases, a leg rash may accompany a serious or life-threatening condition, including a severe allergic reaction called anaphylaxis. Life-threatening conditions include:
Erythema multiforme (type of allergic reaction)
Toxic epidermal necrolysis (skin and mucosal loss due to a severe medication reaction)
What are the potential complications of a leg rash?
In some cases, a leg rash can lead to complications, especially if there is severe itching and scratching that leads to breakdown of the skin. Scratching can introduce bacteria or fungus in the layers of skin, resulting in infections. Complications include:
Bacterial or fungal infection of the skin
Cellulitis (an invasive bacterial or fungal infection of the skin and surrounding tissues)
Open sores and lesions
Permanent change in skin texture, scarring
Permanent skin discoloration
Complications of underlying causes of a leg rash, such as diabetes or peripheral artery disease, can also occur. You can best reduce the risk of complications of a leg rash and its underlying causes by following the treatment plan you and your health care provider develop specifically for you.