Download Cutaneous Signs of Systemic Disease (1)

Erythema Nodosum
Module Instructions

The following module contains hyperlinked
information which serves to offer more
information on topics you may or may not be
familiar with. We encourage that you read all
the hyperlinked information.
Case 1
Case 1: History







HPI: A 35 year-old woman presents with tender
erythematous nodules on the anterior shins. The
lesions appeared over the course of a few days in
crops and have since been resolving with faint bruises
remaining.
ROS: She notes a sore throat over the past 2 weeks.
PMH: none
All: none
Meds: none
FH: non-remarkable
SH: lives in the city with husband and 12 year old child
who also has a sore throat but no rash
Case 1: Exam
VS: T-101.7, HR-90, BP110/70, RR-14, O2sat 100%
Gen: well appearing
HEENT: erythematous
oropharynx with some
exudate
Skin: 5-10 scattered shiny, red
nodules on the anterior shins
bilaterally
Case 1: Question 1

What is the appropriate next step?
a. Biopsy the lesion
b. Drain the nodules
c. Rapid strep test
d. Topical clobetasol
Case 1: Question 1
Answer: c
 What is the appropriate next step?
a. Biopsy the lesion (diagnosis can be
made clinically)
b. Drain the nodules (not appropriate)
c. Rapid strep test
d. Topical clobetasol (may treat the
nodules but not the underlying cause)
Case 1: Lab Findings


Rapid strep test came back positive as well as a
positive ASO titer
Throat culture shows numerous gram positive
cocci in chains consistent with group A strep
(GAS)
Diagnosis

ERYTHEMA NODOSUM


CAUSED BY GROUP A STREP INFECTION!
Patient received penicillin and the EN resolved.
Some Causes of Erythema Nodosum
Erythema nodosum can be precipitated by group A strep
as well as a number of other conditions
 Streptococcal infections
 Tuberculosis
 GI infection with Yersinia, Salmonella, or Shigella
 Systemic fungal infections, such as coccidioidomycosis,
histoplasmosis, sporotrichosis, and blastomycosis
 Sarcoidosis
 Inflammatory bowel disease (Crohn’s > UC)
 EN is the MOST COMMON skin manifestation in
IBD
Erythema Nodosum: Basic Facts


Erythema nodosum is a form of panniculitis
 Panniculitis is an inflammatory disorder of the
subcutaneous fat
 This subcutaneous location results in NODULES with
poorly defined borders deep in the skin on exam
Who gets it?
 Women are 3-6x more likely to develop erythema
nodosum
 Typically occurs in young adult women
Erythema Nodosum: Basic Facts


On exam, erythema nodosum typically presents as:
 Erythematous, shiny tender nodules measuring 110cm in size
 The nodules appear SYMETRICALLY and
BILATERALLY mainly on the anterior shins
 Scattered lesions can also be found on the upper legs,
extensor arms, neck, and rarely face
 Lesions resolve only with a bruise and DO NOT
ulcerate or drain
Additionally, patients may present with malaise, leg edema,
arthritis, arthralgia, fever, HA, and conjunctivitis
Erythema Nodosum: Work-up


In a patient with erythema nodosum who does
not have streptococcal infection, it is important
to order PPD and chest X-ray to rule out
tuberculosis, systemic fungal infection, and
sarcoidosis
In patients with EN and possible IBD, one may
consider a GI referral as up to 15% of IBD
patients develop erythema nodosum
CASE 2
Case 2: History







HPI: A 35 year-old woman presents with tender
erythematous nodules on the anterior shins. The lesions
appeared over the course of a few days in crops and
have since been resolving with faint bruises remaining.
ROS: negative.
PMH: none
All: none
Meds: oral contraceptive Ortho Tri-Cyclen lo
FH: non-remarkable
SH: lives in the city with husband, nobody else with
rash
Case 2: Exam
VS: T-98.6, HR-70, BP110/70, RR-14, O2sat 100%
Gen: well appearing
HEENT: clear oropharynx
Lungs: clear
Skin: 10-20 scattered shiny,
red nodules on the anterior
and lateral leg bilaterally
Case 2: Question 1

What is the likely cause of the patient’s erythema
nodosum?
a. Coccidioidomycosis infection
b. Ortho tri-cyclen lo
c. Tuberculosis
d. Crohn’s disease
Case 2: Question 1
Answer: b
 What is the likely cause of the patient’s erythema
nodosum?
a. Coccidioidomycosis infection (clear lungs, no
fever)
b. Ortho tri-cyclen lo
c. Tuberculosis (clear lungs, no fever)
d. Crohn’s disease (unlikely given lack of bowel
symptoms although could be presenting symptom)
Medications Associated with EN





Oral contraceptives and hormone replacement
are the MOST COMMON medications to cause
EN
Bromides (ex. ipratropium bromide), iodides
Sulfonamides
Echinacea
Pregnancy also leads to higher incidence of EN
suggesting a connection to estrogen
Case 3
Case 3: History






HPI: A 50 year-old woman presents with tender
erythematous nodules on the posterior calves for the
past 2 months.
PMH: none
All: none
Meds: none
FH: non-remarkable
SH: lives in the city, recent immigrant from Central
America
Case 4: Exam
VS: T-98.6, HR-70, BP120/80, RR-18,
O2 sat 98%
Gen: well appearing in NAD
Pulmonary: clear
Skin: tender erythematous
shiny nodules on the
posterior calves bilaterally
Case 4: Question 1

What is the most likely diagnosis?
a. Erythema nodosum
b. Erythema induratum
c. Syphilitic gumma
d. none of the above
Case 4: Question 1
Answer: b
 What is the most likely diagnosis?
a. Erythema nodosum
b. Erythema induratum
c. Syphilitic gumma
d. none of the above
Case 4: Differential Diagnosis
Unlikely EN given the atypical location on the posterior
calf.
Diagnoses considered in this case:
 Erythema induratum (posterior calf, associated with
remote history of tuberculosis, may ulcerate)
 Atypical mycobacterial infection (lesions drain like
abscesses)
 Abscess/ cellulitis
 Subcutaneous fat necrosis from pancreatitis
 Syphilitic gumma (similar to EN but unilateral)
 Sporotrichosis (similar to EN but unilateral)
Case 4: Diagnosis

The diagnosis is erythema induratum
 It is associated with tuberculosis as is EN
 Typical skin lesions
 Erythematous painful plaques on nodules
located on the posterior calves
 Lesions may ulcerate if chronic
 Lesions resolve with scarring and atrophy if they
have ulcerated
Case 4: Continued

If a patient like the one in case 4 had not be
diagnosed for many years, the lesions would be
more likely to ulcerate
On exam, pt has bilateral
ulcerated nodules with
overlying crust and
surrounding rim of
erythema
Some Additional Points
on Erythema Nodosum
Erythema Nodosum: Work-up


Erythema nodosum typically suggests an
underlying disease making it important to rule
out these causes whenever a patient presents
with the condition.
40% of cases are idiopathic and for persistent
lesions a biopsy is typically necessary, making a
referral to a dermatologist useful

The lesion requires a deep punch biopsy or even an
incisional or excisional biopsy due to its depth
Erythema Nodosum: Treatment


Typically EN is a result of underlying disease
and the first line treatment is to treat the
underlying disease
Other treatments:
Bed rest and support stalkings
 Supersaturated potassium iodide (SSKI) 5-15 gtt
TID beginning at 5gtt and titrating up
1 additional gtt/day OR 300mg tablet TID

 Be cautious of potential HYPOTHYROIDISM
Erythema Nodosum: Treatment




If lesions persist, biopsy is indicated and
intralesional steroid injection is useful
Systemic steroids are effective if the underlying
cause is not infectious
For erythema nodosum, SSKI is effective as well
Lesions typically resolve in 3-6wks, lesions that last
longer may suggest a different diagnosis
END OF MODULE