Page 132 - Journal of Special Operations Medicine - Winter 2014

An Ongoing Series

Erythema Nodosum

John A. Vigilante, MD; Jane Scribner, MD

ABSTRACT
An active duty female Sailor reports to your clinic com- Figures 1 and 2 Clinical photographs of lesions on the legs.
plaining of tender nodules to her legs beginning 1.5 weeks
ago. She is diagnosed with erythema nodosum (EN), a
painful disorder of the subcutaneous fat that is usually
self-limited but may be a clue to an additional underlying
medical diagnosis. This article reviews the pathophysiol-
ogy, causes, course, diagnosis, and management of EN.

Keywords: subcutaneous nodules, erythema nodosum,
panniculitis

Introduction
Dermatologic complaints are common in primary care
and may be a sign of systemic disease. To generate an ac-
curate differential diagnosis, it is essential to obtain a de- The lesions shown in Figures 1 and 2 are subcutaneous
tailed history and properly identify and characterize the nodules with overlying hyperpigmentation located on
skin findings. This article describes a case of tender skin the anterior upper and lower legs. Tender, erythematous,
nodules, explains the disease process, and discusses the subcutaneous nodules located symmetrically on the ex-
appropriate evaluation for a patient with these symptoms. tensor surfaces of the lower extremities are clinically
consistent with EN. Chest radiography and antistreptol-
ysin-O titer, pregnancy test, purified protein derivative,
Case Presentation
complete blood count, liver function tests, antinuclear
A 23-year-old female Sailor presents to the clinic for antibody, C-reactive protein levels, and stool studies
evaluation of new-onset skin lesions. One and one-half were normal. The patient’s OCP and antibiotics were
weeks earlier, the patient developed tender, nonpruritic discontinued, and she was given naproxen 250mg by
nodules on both legs. She also complained of concur- mouth twice daily and 1 week of bed rest, with resolu-
rent nausea and emesis. The patient was initially treated tion of her symptoms.
with oral antibiotics (sulfamethoxazole-trimethoprim
and cephalexin) for presumed abscesses, with no relief
of her symptoms. Additionally, she began taking an oral Discussion
contraceptive pill (OCP) after the lesions had formed. Erythema nodosum is a nonspecific cutaneous reaction
The patient otherwise feels well and denies other skin pattern thought to involve a hypersensitivity response,
complaints, diarrhea, arthralgias, fever, chills, or night which represents inflammation of the septa of the sub-
sweats. Figures 1 and 2 are photographs of the patient. cutaneous fat. The incidence is one to five per 100,000
1
How would you describe these lesions? persons. EN occurs more often among women, with a
1
male-to-female ratio of 1:6. It can affect patients of
2–4
What is the likely diagnosis? What diagnostic evaluations any age, but peak incidence occurs in adults aged 20 to
should be performed? How would you treat this disease? 30 years. 1

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