Causes and Treatment of Erythema Nodusum

QUESTION: I have been diagnosed with a disease called "erythema nodusum", a
situation that I find very disturbing and a bit painful to boot. Can you tell
me what causes the disease, and what treatments I should be taking? As of
now, my doctor has done little but reassure me that it will all pass. I need
to know more. Thank you.
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ANSWER: Erythema nodosum can be the sign that alerts a physician to many
possible diagnoses. The typical marks of erythema nodusum are extremely
tender, bright-red nodules that seem to lie just below the skin and are spread
symmetrically over both lower extremities, although they can also appear on
upper extremities. As they fade, they often resemble bruises.
Erythema nodosum is considered to be an immunologic response to a wide
variety of conditions that may be present in the body such as tuberculosis,
sarcoidosis, inflammatory bowel disease and lymphoma. However, the three most
common causes of erythema nodosum are streptococcal pharyngitis, sarcoidosis
and medications (especially birth control pills and sulfonamides), of which
strep throat (pharyngitis) is the most likely cause in children. However, in
a large percentage of cases, despite intensive investigations, no specific
cause can be found. In this case it is labeled "idiopathic erythema nodosum",
and this is the most likely diagnosis in your case.
Many patients with erythema nodosum also suffer from fever, malaise,
arthralgias and arthritis. The disease is diagnosed by obtaining a biopsy of
the lesion and submitting it to a pathologist for evaluation.
In addition, a careful history is a must, as well as a thorough physical
examination. Laboratory testing is part of the process, and the choice of
tests depend upon the situation in which the nodules are found and may include
a complete blood count, chest x-ray and skin test for TB.
When a specific cause can be determined, treatment is focused on removing
the cause. For cases of strep throat, long term treatment with an antibiotic
for as long as 1 year may help.
When the underlying disease is removed, the nodules disappear as well.
In the case of idiopathic disease, complete healing of a lesion usually occurs
within a month or two of its appearance, even without specific therapy. And
that is why your doctor has been reassuring you without particular
medications. Only supportive treatment, such as bed rest, is necessary for
some patients with erythema nodosum. Patients with extremely tender nodules
usually require salicylates or other nonsteroidal anti-inflammatory agents to
help relieve the pain.