A painful, red leg is a condition that can have various causes. The most common are a thrombosed leg, inflammation of the skin (erysipelas) and joint inflammation (arthritis). Based on the complaints, age, medical background and risk factors, a cause can often be found with targeted diagnostics. This article describes the most common causes, the associated diagnostics and their treatment.
Table of contents
- Anatomy
- Thrombotic leg
- Erysipelas
- Arthritis
How the calf muscle pump and venous valves work (click to enlarge) / Source: OpenStax College, Wikimedia Commons (CC BY-3.0)
Anatomy
The human leg is divided into the thigh, knee, lower leg, ankle and foot. It has a number of joints (hinge points), consisting of the hip, the knee, the upper and lower hocks and the joints of the foot. It is supplied with oxygen-rich blood by arteries, which after consumption is returned with low oxygen through the veins. When walking, the sole of the foot and calf muscles function as a mechanical pump to pump oxygen-poor blood against gravity. The venous vessels contain valves that prevent flow against gravity.
Thrombotic leg
Cause and complaints
Redder and thicker right leg due to a deep vein thrombosis / Source: James Heilman, MD, Wikimedia Commons (CC BY-SA-3.0)
In the case of a thrombosed leg, a blood clot has developed due to prolonged stagnation of the blood. This usually grows over time, resulting in occlusion of the venous vessel. The normal function of the clot is to prevent blood from flowing out of the vessels after a wound. However, in the case of a thrombosed leg, this function is disrupted and a clot has formed in the vessel itself. The symptoms of a thrombosed leg consist of a painful, warm, red and/or swollen leg.
Risk factors
There are a number of risk factors that increase the risk of developing a thrombosed leg, these include:
- A broken bone or surgery on the leg
- A recent operation in any area
- A recent pregnancy or postpartum period
- Long-term immobilization of the leg (e.g. a car or plane trip longer than 6 hours or a plaster cast)
- Certain types of oral contraception (‘the pill’)
- Serious diseases that affect clotting such as cancer
- Overweight
- Clotting disorders (e.g. factor V Leiden)
- As age progresses, the chance of occurrence increases
Diagnostics
One of the most common forms of diagnosis is an ultrasound scan of the venous vascular system of the leg. This often allows a clot to be clearly identified. Another form of diagnostics is a so-called d-dimer. This value is determined in the blood and is particularly applicable when there is a relatively low suspicion of a thrombosed leg.
Prevention
Prevention is an important part of a thrombosed leg. It is wise to use the leg as frequently as possible during prolonged periods of sitting still, for example by walking a bit during a break. It also helps to drink enough. In case of immobilization with a plaster cast, a mild form of blood thinning can be prescribed, for example fraxiparine.
Therapy
The standard treatment for a thrombosed leg consists of so-called anticoagulants (blood-thinning agents), preventing causes as far as possible (for example stopping oral contraception) and prescribing an elastic stocking to treat the swelling. It often takes several months for the clot to dissolve. The anticoagulants consist of subcutaneous injections with a form of heparin. At the same time, tablets are started (for example Sintrom or Marcoumar). The injections work very quickly, the tablets require days to charge. As soon as the blood has sufficiently anticoagulated, the injections can be stopped. The duration of treatment is usually between three and six months.
Complication
One of the complications of a thrombosed leg is the formation of a clot that gets stuck in the pulmonary circulation. The part of the clot then becomes dislodged in the leg vessel, continues its way to the superior vena cava and the right atrium and then becomes blocked in the arterial pulmonary circulation. This can cause shortness of breath and chest pain and is definitely a reason for urgent contact with a doctor.
Reddish right leg due to erysipelas / Source: Grook Da Oger, Wikimedia Commons (CC BY-SA-3.0)
Erysipelas
Cause and complaints
Erysipelas (other terms: bell rose or erysipelas) is an acute, bacterial infection of the skin that spreads through the lymphatic vessels. Complaints arise of a warm, red and painful leg. In addition, people suffer from general malaise and fever. It is characterized by a so-called lymphangitis picture, the formation of stripe-shaped redness in the direction of the lymphatic vessels. There is a so-called porte dentree, the place where the bacteria has entered the body. This is often a wound. People with diabetes mellitus, older age and fluid in the legs (edema) have an increased risk of a complicated course.
Diagnostics
In general, the doctor’s clinical view is sufficient to make the diagnosis. Blood tests including inflammation values can provide an idea of the course of the disease. Blood cultures can be of added value if an atypical pathogen is expected.
Therapy
The standard treatment is antibiotics, usually flucloxacillin. This is often given in the hospital via an IV, but tablets are also available. A treatment usually lasts 7 to 10 days. It may take two weeks for the skin to return to normal. Increased redness or becoming increasingly ill during the antibiotic treatment are not a good sign. It is then important to contact a doctor.
Arthritis
Arthritis (joint inflammation) can be a cause of a red, swollen and painful leg. The causes are diverse and include an autoimmune disorder that causes antibodies to be formed against one’s own tissue, infection of an (artificial) joint and osteoarthritis. The treatment is as diverse as the number of causes. Pain relief, especially paracetamol and NSAIDs, can relieve the symptoms. In the case of inflammation of one joint (monoarthritis), an infectious cause (for example with bacteria) is likely, while multiple joints may indicate a different cause.
In summary, there are a number of different causes that can cause a painful and red leg. In general, it is wise to consult a doctor in a timely manner for this condition, partly because further problems can be prevented by adequately treating a specific cause (for example antibiotics for erysipelas).
