The skin condition erythema nodosum causes red, tender, and painful bumps to form on the lower legs and occasionally on other parts of the body. The disease is neither serious nor contagious, but can indicate an underlying issue. The purpose of this blog post is to explain what causes erythema nodosum, how to diagnose it, how to treat it, and how to prevent it.
Erythema nodosum occurs when the layer of fat under the skin becomes inflamed or irritated. The exact cause of this inflammation is not always known, but it can be triggered by:
An infection, such as strep throat, tuberculosis, hepatitis B, or coccidioidomycosis.
A medication, such as the contraceptive pill, antibiotics, or sulfa drugs.
A health condition, such as inflammatory bowel disease, sarcoidosis, cancer, or pregnancy.
An allergic reaction, such as to food, insect bites, or chemicals.
In some cases, no specific cause can be identified. This is called idiopathic erythema nodosum.
There are red, tender, and painful bumps on the shins of people with erythema nodosum. The bumps can range in size from a grape to an orange and may feel warm to the touch. They usually appear over a period of one to two weeks, and then slowly fade into flat, purple or brown patches, similar to bruises. They do not leave scars, but it may take several weeks or months for them to disappear completely.
Other symptoms that may accompany erythema nodosum include:
Fever
Malaise (feeling unwell)
Fatigue
Joint pain
Swollen ankles
Diarrhea
Abdominal pain
The severity and duration of the symptoms may vary from person to person, depending on the cause and the individual's immune system.
A doctor can usually diagnose erythema nodosum by observing the bumps and feeling them. Sometimes, a skin biopsy may be performed to confirm the diagnosis and rule out other conditions. A skin biopsy involves taking a small sample of skin tissue and examining it under a microscope.
To find out the underlying cause of erythema nodosum, the doctor may also order some tests, such as:
Blood tests, to check for signs of infection, inflammation, or autoimmune disorders.
Throat swab, to test for streptococcal infection.
Chest x-ray, to look for signs of tuberculosis or sarcoidosis.
Skin test, to check for exposure to coccidioidomycosis.
Urine test, to check for signs of kidney problems.
Stool test, to check for signs of inflammatory bowel disease.
The type and number of tests may vary depending on the suspected cause and the individual's medical history.
The treatment of erythema nodosum depends on the cause and the severity of the symptoms. The main goals of treatment are to:
Relieve the pain and inflammation of the skin bumps.
Treat the underlying condition or infection, if any.
Prevent complications or recurrence of the condition.
Some of the treatment options include:
Resting and elevating the affected legs, to reduce swelling and discomfort.
Applying cold or warm compresses, to soothe the skin and ease the pain.
Wearing compression stockings, to improve blood circulation and prevent blood clots.
Taking anti-inflammatory medicines, such as ibuprofen or naproxen, to reduce inflammation and pain. These medicines should be used with caution and under the doctor's guidance, as they may have side effects or interact with other medications.
Taking antibiotics, if the cause is a bacterial infection, such as strep throat or tuberculosis.
Taking antiviral medicines, if the cause is a viral infection, such as hepatitis B.
Taking antifungal medicines, if the cause is a fungal infection, such as coccidioidomycosis.
If the cause is an autoimmune disorder, such as inflammatory bowel disease or sarcoidosis, corticosteroids can be taken. Although these medicines can suppress the immune system and reduce inflammation, they can also have serious side effects, so it is important to consult with your doctor before taking them.
It may be necessary to take other medicines, such as colchicine, potassium iodide, or thalidomide, if the cause is unknown or other treatments do not work. As well as their benefits, these medicines may have serious side effects, so they should only be taken under doctor's supervision.
In some cases, erythema nodosum may resolve on its own without any specific treatment, especially if the cause is mild or transient. However, it is important to consult a doctor if the symptoms persist or worsen, or if there are signs of complications, such as:
Severe pain or swelling of the legs
Difficulty walking or moving the legs
Skin ulcers or infections
Blood clots or deep vein thrombosis
Kidney problems or kidney failure
Eye problems or vision loss
Lung problems or breathing difficulties
Heart problems or chest pain
The prevention of erythema nodosum depends on the cause and the individual's risk factors. Some of the general measures that may help prevent or reduce the risk of erythema nodosum include:
Avoiding or limiting exposure to potential triggers, such as allergens, chemicals, or insect bites.
Taking care of the skin, by keeping it clean, moisturized, and protected from injuries or infections.
Following a healthy lifestyle, by eating a balanced diet, drinking plenty of water, exercising regularly, and managing stress.
Quitting smoking, as smoking can impair the immune system and increase the risk of infections and inflammation.
Getting vaccinated, as some vaccines can protect against certain infections that may cause erythema nodosum, such as hepatitis B or tuberculosis.
Taking medicines as prescribed, and informing the doctor of any side effects or allergies to medications.
Seeking medical attention promptly, if there are signs of infection, inflammation, or other health problems.
Occasionally, erythema nodosum can cause red, tender, and painful bumps on the lower legs, as well as other parts of the body. Even though erythema nodosum isn't a serious disease or contagious, it may indicate an underlying issue. Several factors can cause erythema nodosum, including an infection, a medication, a health condition, or an allergic reaction. Rest, compresses, medicines, or other therapies may be used to treat erythema nodosum, depending on its cause and severity. In order to prevent erythema nodosum, you can avoid or limit exposure to potential triggers, take good care of your skin, follow a healthy lifestyle, quit smoking, get vaccinated, take medicines as prescribed, and seek medical attention as soon as possible. Even though erythema nodosum can be distressing and uncomfortable, it can be managed and treated with proper care and guidance from a doctor.
