Erythema Nodosum
Basic Dermatology Curriculum
Last updated March 23, 2011
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Modules Instructions
 The following module contains a number
of blue, underlined terms which are
hyperlinked to the dermatology glossary,
an illustrated interactive guide to clinical
dermatology and dermatopathology.
 We encourage the learner to read all the
hyperlinked information.
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Goals and Objectives
 The purpose of this module is to help medical students
develop a clinical approach to the evaluation and initial
management of patients presenting with erythema
nodosum.
 By completing this module, the learner will be able to:
• Identify and describe the morphology of erythema nodosum
• Name conditions associated with erythema nodosum
• Recommend an initial treatment plan for a patient with
erythema nodosum
• Discuss when to refer to a patient with erythema nodosum to
a dermatologist
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Case One
Mrs. Cheryl Mosely
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Case One: History
 HPI: Mrs. Mosely is a 35-year-old woman who presents to her primary
care physician with tender red “bumps” on her anterior shins. The lesions
appeared over the course of a few days and have started to resolve with
faint bruises remaining. She also reports a recent history of a sore throat
and fever two weeks ago, which improved after a course of antibiotics.
 PMH: no major illness or hospitalizations
 Medications: none aside from recent antibiotic course
 Allergies: none
 Family history: noncontributory
 Social history: lives with husband and 12-year-old child who also had a
sore throat
 Health-related behaviors: no tobacco, alcohol, or drug use
 ROS: no cough or rhinorrhea
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Case One: Exam




Vital signs: normal
Gen: well-appearing
HEENT: normal
Skin: multiple scattered
shiny, red nodules on
the anterior shins
bilaterally
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Case One, Question 1
 What is the appropriate next step?
a.
b.
c.
d.
Anti-Streptolysin O titer
Biopsy the lesion
Drain the nodules
Topical steroid ointment
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Case One, Question 1
Answer: a
 What is the appropriate next step?
a. Anti-Streptolysin O titer
b. Biopsy the lesion (diagnosis can be made
clinically)
c. Drain the nodules (lesions are more
inflammatory vs. abscess)
d. Topical steroid (not effective)
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Diagnosis: Erythema Nodosum
 Mrs. Mosely’s recent history of sore throat
and fever is suggestive of acute
pharyngitis. Her ASO titer came back
elevated.
 The lesions on her legs were diagnosed
as erythema nodosum.
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Erythema Nodosum (EN)
 Characterized by the presence of painful, erythematous,
non-ulcerative nodules
• Often symmetric distribution, located bilaterally below the
knees (mainly on the anterior tibial surface)
• Lesions evolve from bright red to brown-yellow, resembling
old ecchymoses
• Old and new lesions often coexist
• Patients may also present with fever, fatigue, and arthralgias
 The morphology of the lesion, a deep nodule, identifies
EN as an inflammatory disease of the fat (called a
panniculitis)
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Case One, Question 2
 Which of the following history and clinical
items are commonly found in patients with
EN?
a.
b.
c.
d.
e.
Patient is female
Recent fever
Recent upper respiratory infection
Use of oral contraceptives
All of the above
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Case One, Question 2
Answer: e
 Which of the following history and clinical
items are commonly found in patients with
EN?
a.
b.
c.
d.
e.
Patient is female
Recent fever
Recent upper respiratory infection
Use of oral contraceptives
All of the above
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EN: The Basics
 Can occur at any age, but most cases appear between 2nd
and 4th decades
 15-20x more common in women than men
 EN is not a disease, but a reaction pattern to a variety of
factors including infections, medications, and systemic
diseases
 Diagnosis of EN should always be followed by a search for the
underlying etiology
 Streptococcal disease is the most common cause of EN in
children
 Drugs, sarcoidosis, and inflammatory bowel disease (IBD) are
commonly associated disorders in adults with EN
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Conditions Associated with EN
 Idiopathic > 50%
 Infections
• Streptococcal infections, tuberculosis, histoplasmosis,
coccidiomycosis
 Drugs
• Oral contraceptive pills, sulfonamides
 Neoplasms
• Lymphoma, leukemia, renal cell carcinoma
 Miscellaneous Conditions
• Sarcoidosis, inflammatory bowel disease
Note: Only a few common causes of EN are mentioned. EN is associated with a
wide variety of disease processes and medications.
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Case One, Question 3
 Which of the following statement
regarding treatment of EN is true?
a.
b.
c.
d.
Antihistamines are often used for treatment
Anti-inflammatories should be avoided
EN tends to be self-limited
Systemic steroids are of no value
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Case One, Question 3
Answer: c
 Which of the following statement regarding
treatment of EN is true?
a. Antihistamines are often used for treatment (Not true)
b. Anti-inflammatories should be avoided (Not true. Antiinflammatories are often used in the treatment of EN)
c. EN tends to be self-limited
d. Systemic steroids are of no value (Not true. Systemic
steroids can be used if underlying infection and
malignancy have been excluded)
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EN: Treatment
 EN is usually self-limited or resolves with treatment of the
underlying disorder
• Lesions heal without atrophy or scarring
• Eruption generally lasts from 3 to 6 weeks, and recurrences are
frequent
 Treatment is typically symptomatic
• Supportive measures and pain control are recommended
 The use of systemic glucocorticoids should be weighed
against the possibility of masking an underlying neoplastic,
inflammatory, or infectious condition
 Oral potassium iodide therapy is another treatment option
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Case Two
Ms. Beverly Prescott
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Case Two: History
 HPI: Ms. Prescott is a 35-year-old woman who presents to her
primary care provider with tender red nodules on her anterior shins.
Some of the lesions appear to be resolving, but others are still
appearing. No sick contacts or anyone else with a rash.
 PMH: no major illnesses or hospitalizations
 Allergies: none
 Meds: oral contraceptive pills (unable to recall the name)
 Family history: father with history of BCC
 Social history: lives with a friend in an apartment, works in
advertising
 Health-related behaviors: alcohol use (1-2 drinks per week), no
tobacco or drug use
 ROS: negative
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Case Two: Exam
 Vital Signs: normal
 HEENT: normal exam
 Lungs: clear to
auscultation
 Skin: multiple
scattered shiny,
erythematous nodules
on the anterior lower
extremities
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Case Two, Question 1
 The primary care provider suspects erythema
nodosum. What else should be considered as
part of the initial evaluation?
a. Make sure a thorough medical history and
review of systems was performed
b. Order an ASO
c. Place a PPD
d. All of the above
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Case Two, Question 1
Answer: d
 The primary care provider suspects erythema
nodosum. What else should be considered as
part of the initial evaluation?
a. Make sure a thorough medical history and
review of systems was performed
b. Order an ASO
c. Place a PPD
d. All of the above
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Case Two, Question 2
 What is the likely cause of Ms. Prescott’s
erythema nodosum?
a.
b.
c.
d.
Crohn’s disease
Oral contraceptives
Sarcoidosis
Tuberculosis
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Case Two, Question 2
Answer: b
 What is the likely cause of the Ms. Prescott’s
erythema nodosum?
a. Crohn’s disease (Possible that EN is the presenting
feature of IBD, but her OCP use is a more likely
cause in this case)
b. Oral contraceptives
c. Sarcoidosis (Possible, but less likely)
d. Tuberculosis (No known risk factors, but a PPD
placement would be prudent)
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Case Three
Ms. Maria Ojeda
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Case Three: History
 HPI: Ms. Ojeda is a 50-year-old woman who presents to the
general medicine clinic with tender red nodules on her
posterior calves for the past 2 months.
 PMH: last visit to the doctor was 10 years ago, no major
illnesses or hospitalizations
 Medications: none
 Allergies: none
 Family history: mother with hypertension
 Social history: lives with multiple family members in the city,
recently moved to the US from Guatemala
 Health-related behaviors: no tobacco, alcohol, or drug use
 ROS: occasional fatigue
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Case Three: Exam
 Vital signs: normal
 Physical exam normal
except for: tender
erythematous shiny nodules
on the posterior calves
bilaterally
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Case Three, Question 1
 What is the most likely diagnosis?
a.
b.
c.
d.
Erythema induratum
Erythema nodosum
Polyarteritis nodosa
Syphilitic gumma
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Case Three, Question 1
Answer: a
 What is the most likely diagnosis?
a. Erythema induratum
b. Erythema nodosum (Characterized by painful,
erythematous, non-ulcerative nodules usually located on
anterior lower legs)
c. Polyarteritis nodosa (Characterized by painful,
subcutaneous nodules. Livedo reticularis may be
present)
d. Syphilitic gumma (Painless subcutaneous nodules,
enlarge, attach to the overlying skin, and eventually
ulcerate)
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Erythema Induratum
 Erythema induratum is a panniculitis
characterized by tender subcutaneous nodules
usually located on the lower posterior calf
 Erythema induratum is chronic and more
commonly affects middle-aged women
 Occurs in the setting of tuberculosis (latent)
• PPD will usually be positive
 Lesions can resolve spontaneously with or without
ulceration and often heal with scarring
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When to Biopsy Panniculitis
 For persistent lesions (> 6wks) or when the
diagnosis is unclear a biopsy is typically
necessary and these patients should be
referred to a dermatologist
 A deep incisional or excisional biopsy
should be obtained for best visualization
because a punch biopsy is likely to produce
an inadequate sample
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Take Home Points
 EN is characterized by painful, erythematous, nonulcerative subcutaneous nodules.
 Most cases appear between the 2nd and 4th decade
of life and is more common in women.
 There are numerous etiologies for EN including
infections, medications, neoplasms, and other
miscellaneous conditions.
 Streptococcal infection is the most common
etiologic factor in children.
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Take Home Points
 Drugs, sarcoidosis, systemic fungal infections
(coccidiomycosis, histoplasmosis) and inflammatory
bowel disease are commonly associated disorders
in adults with EN.
 EN tends to be self-limited or resolves with
treatment of the underlying disorder.
 Erythema induratum can be distinguished from EN
by the chronic time course, location on the posterior
calf, ulceration of the lesions and association with
latent tuberculosis.
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Acknowledgements
 This module was developed by the American
Academy of Dermatology Medical Student Core
Curriculum Workgroup from 2008-2012.
 Primary authors: Sarah D. Cipriano, MD, MPH; Eric
Meinhardt, MD; Timothy G. Berger, MD, FAAD.
 Peer reviewers: Peter A. Lio, MD, FAAD; Carlos
Garcia, MD.
 Revisions and editing: Sarah D. Cipriano, MD, MPH;
Jillian W. Wong. Last revised March 2011.
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End of the Module
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Philadelphia, Pa: Saunders Elsevier; 2006: 487-489.
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End of the Module
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2007;26:114-125. Requena Luis, Yus Evaristo S, Kutzner Heinz,
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