A panniculitis marked by the sudden formation of painful nodes on the extensor surfaces of the lower extremities, with lesions that are self-limiting but tend to recur; associated with arthralgia and fever; may be the result of drug sensitivity or associated with sarcoidosis and various infections. Deep biopsies show a septal panniculitis with infiltration by lymphocytes and scattered multinucleated giant cells. Syn: Nodal fever.
Erythema nodosum is an inflammatory disorder that is characterized by tender, red nodules ranging in size from 1 to 5 centimeters most commonly located over the shins but occasionally involving the arms or other areas.
Erythema nodosum is a type of skin inflammation that is located in a certain portion of the fatty layer of skin. Erythema nodosum (also called EN) results in reddish, painful, tender lumps most commonly located in the front of the legs below the knees. The tender lumps, or nodules, of erythema nodosum range in size from 1 to 5 centimeters. The nodular swelling is caused by a special pattern of inflammation in the fatty layer of skin.
Erythema nodosum can be self-limited and resolve on its own in three to six weeks. Upon resolution, it may leave only a temporary bruised appearance or leave a chronic indentation in the skin where the fatty layer has been injured.
There are several scenarios for the outcome of erythema nodosum. Typically, these areas of nodular tenderness range in size from about a dime to a quarter and they may be tender and inflamed off and on for a period of weeks. They usually then resolve spontaneously, each one of the little areas of inflammation shrinking down and then becoming flat rather than raised and inflamed. They leave a bruised appearance. Then, they resolve spontaneously completely. Other lesions can sometimes pop up elsewhere. This may occur for periods of weeks to months and then eventually goes away. However, chronic erythema nodosum that may last for years is another pattern. Chronic erythema nodosum, with intermittent recurrences, can occur with or without an underlying disease present.
Erythema nodosum can develop in persons of any age, sex, and ethnicity. Young adults are particularly susceptible to developing erythema nodosum. Moreover, women are 4 times more likely than men to be affected.
Approximately 30-50% of cases of erythema nodosum have no underlying cause. However, an associated medication, infection, or health condition may be found in the remainder of cases.
Erythema nodosum may develop in people on these medications:
Birth control pills.
- Estrogen pills.
- Antibiotics (such as sulfonamides or penicillin).
Erythema nodosum may occur in persons with one of the following infections:
Streptococcal infections (such as strep throat).
- Intestinal infections.
- Pneumonia (viral or bacterial).
- Fungal infections (such as coccidioidomycosis or histoplasmosis).
Erythema nodosum may be seen in individuals with one of these underlying medical conditions:
- Inflammatory bowel disease (ulcerative colitis or Crohn's disease).
- Lymphoma or leukemia.
Erythema nodosum may be self-limited and go away on its own in 3 to 6 weeks. If treatment is needed, the underlying condition is treated and simultaneously treatment is directed toward the erythema nodosum. This can include antiinflammatory drugs and cortisone by mouth or injection. Colchicine is sometime used effectively to reduce inflammation.
Although erythema nodosum may occur on its own, it is more often associated with a medication or with an underlying infection or medical condition. Therefore, it is important to see a physician in order to investigate any possible health problems.
Symptoms include the following:
- General ill feeling (malaise).
- Joint aches.
- Skin redness, inflammation, or irritation.
- Swelling of the leg or other affected area.
- The red and inflamed skin symptoms may regress to a bruise-like appearance.
Individual nodules of erythema nodosum usually last from 1-2 weeks, but new lesions may continue to appear for up to 6 weeks. When an individual lesion of erythema nodosum has resolved, it may leave behind a temporary bruise, which subsequently fades to normal-appearing skin.
Causes and Risk factors:
The causes of erythema nodosum include medications (sulfa-related drugs, birth control pills, estrogens, iodides and bromides), strep throat, cat scratch disease, fungal diseases, infectious mononucleosis, sarcoidosis, Behcet's disease, inflammatory bowel disease (Crohn's disease and ulcerative colitis), and normal pregnancy. In many cases, no cause can be determined.
Currently, the most common cause of EN is streptococcal infection in children and streptococcal infection and sarcoidosis in adults. Numerous other causes have been reported.
The causes reported most often in the literature are as follows:
Bacterial infections include the following:
Streptococcal infections: These infections are one of the most common causes of EN.
- Tuberculosis: An important cause in the past, tuberculosis has decreased dramatically as a cause for EN but still must be excluded.
- Yersinia enterocolitica: This gram-negative bacillus causes acute diarrhea and abdominal pain and is a common cause of EN in France and Finland. Mycoplasma pneumoniae infection may cause EN.
- Leprosy: Clinically, erythema nodosum leprosum resembles EN, but the histologic picture is that of leukocytoclastic vasculitis.
- Lymphogranuloma venereum may cause EN.
- Salmonella infection may cause EN.
- Campylobacter infection may cause EN.
Usually, erythema nodosum is a straightforward, simple diagnosis for a doctor to make simply by examining a patient and noting the typical firm area of raised tenderness that is red along with areas which have had lesions resolved, which might show a bruised-like appearance. It is not a difficult diagnosis for an experienced doctor. It does not typically require other investigative tests.
Sometimes a biopsy is done for confirmation, for example, if a patient presented with an isolated, singular area and a doctor was unable to make a diagnosis based on its appearance. The biopsy of the deeper layers of tissue of skin can prove that it is erythema nodosum. Those layers would show the specific fatty layers of inflammation.
Treatment of erythema nodosum should be directed to the underlying associated condition, if identified. Usually, nodules of erythema nodosum regress spontaneously within a few weeks, and bed rest is often sufficient treatment. Aspirin and nonsteroidal anti-inflammatory drugs such as oxyphenbutazone, in a dosage of 400 mg per day, indomethacin, in a dosage of 100 to 150 mg per day, or naproxen, in a dosage of 500 mg per day, may be helpful to enhance analgesia and resolution. If the lesions persist longer, potassium iodide in a dosage of 400 to 900 mg daily or a saturated solution of potassium iodide, 2 to 10 drops in water or orange juice three times per day, has been reported to be useful. The mechanism of action of potassium iodide in erythema nodosum is unknown, but a theoretical mechanism involves its stimulation of heparin release from mast cells. Heparin acts to suppress delayed hypersensitivity reactions. The reported response in some patients with erythema nodosum lesions to heparinoid ointment under occlusion supports this proposed mechanism of action. On the other hand, potassium iodide also inhibits neutrophil chemotaxis. Potassium iodide is contraindicated during pregnancy, because it can produce a goiter in the fetus. Severe hypothyroidism secondary to exogenous intake of iodide has been also described in patients with erythema nodosum treated with potassium iodide.
Systemic corticosteroids are rarely indicated in erythema nodosum and before these drugs are administered an underlying infection should be ruled out. When administered, prednisone in a dosage of 40 mg per day has been followed by resolution of the nodules in few days. Intralesional injection of triamcinolone acetonide in a dosage of 5 mg/ml, into the center of the nodules may cause them to resolve.
Some patients may respond to a course of colchicine, 0.6 to 1.2 mg twice daily. Hydroxychloroquine, 200 mg twice a day, has also been reported to be useful in a recent report.
Medicine and medications:
Erythema nodosum often regresses spontaneously; symptomatic relief using NSAIDs (eg, acetyl salicylic acid, ibuprofen, naproxen, and indomethacin) usually is all that is required. Corticosteroids are effective but seldom necessary in self-limited disease. Recurrence of erythema nodosum following discontinuation of treatment is common, and underlying infectious disease may be worsened. Potassium iodide may relieve lesional tenderness, arthralgia, and fever. Colchicine has been used in a few refractory cases with good results. Note that some of the medications used to treat erythema nodosum have been implicated as rare causes of erythema nodosum in individuals with hypersensitivity to the drugs.
DISCLAIMER: This information should not substitute for seeking responsible, professional medical care.