The Red Leg
Module Instructions
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Case 1
Case 1: History
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HPI: A 65 year old female complains of one week of
worsening right lower extremity pain. She states that she
has also had a fever and chills since she returned from a
camping trip last week. She states that her leg does not itch.
PMH: none
All: none
Meds: none
FH: non-remarkable
SH: lives in the city with her husband. Denies alcohol,
smoking, IV drug use
ROS: +fever, chills
Case 1: Exam
How would you
describe these skin
findings?
Case 1: Exam
On exam,
VS: T-101.4, HR-80, BP-110/70,
RR-14, O2sat 100%
Ext: +inguinal LAD
Skin: erythematous plaque with
ill-defined borders over the
right medial malleolus. The
lesion is tender to palpation.
LABS: WBC-12, Hct 44, Plt 335
Case 1: Question 1

Which of the following are important things to
look for on exam of this patient with a red leg?
a. Fever
b. Elevated white blood cell count
c. Lymphadenopathy
d. Streaking
e. All of the above
Case 1: Question 1
Answer: e
 Which of the following are important things to
look for on exam of this patient with a red leg?
a. Fever
b. Elevated white blood cell count
c. Lymphadenopathy
d. Streaking
e. All of the above
What is Lymphatic Streaking?
Lymphatic
Streaking
Lymphatic streaking is seen when the lymphatic vessels are involved and
inflamed!
Case 1: Question 2
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What is the most likely diagnosis?
a. cellulitis
b. tinea corporis
c. stasis dermatitis
d. hemophilia
Case 1: Question 2
Answer: a
 What is the most likely diagnosis?
a. cellulitis
b. tinea corporis (less likely to have a fever and
would expect to see scale)
c. stasis dermatitis (would not expect lymphadenopathy,
likely would see some pruritus)
d. hemophilia (would not see fever or lymphadenopathy
and bleeding is typically deeper and into joint spaces)
Diagnosis: Cellulitis
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Cellulitis is a very common infection occurring in up to
3% of people per year and is most commonly found in
middle aged men
Cellulitis results from an infection of the dermis that
often begins following either a wound or fungal
infection
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Remember to inquire about IV drug use in the area!
Group A beta hemolytic strep and Staph aureus are the
most common causal pathogens
It is important to recognize and treat cellulitis early as it
may lead to SEPSIS or NECROTIZING FASCIITIS!
Cellulitis: Clinical Presentation
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Cellulitis typically presents as a rapidly spreading
erythematous, non-fluctuant tender plaque
 The lower leg is most commonly involved
 There is often lymphatic streaking
The patient may be febrile and toxic
 There may be an elevated WBC count
 Lymphadenopathy may be present
Cellulitis: Pearls
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Cellulitis is almost always UNILATERAL!
 Bilateral lower extremity cellulitis almost never
happens, so resist making this diagnosis in
patients with bilateral painful red legs with NO
fever, white count, LAD, or streaking
Tinea pedis serves as a common portal of entry for
bacteria, especially in cases of recurrent cellulitis
 It is important to always look for and treat tinea
pedis in cellulitis patients!
Erysipelas
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Erysipelas is a superficial cellulitis that extensively
involves the lymphatics
 Often caused by group A strep and affects older
adults
There are raised, firm, shiny plaques on exam
These plaques may develop overlying blisters (bullae)
It often involves the face or lower extremities
It is often associated with white count >20,000
It is often preceded by chills, fever, headache, vomiting,
and joint pain
Erysipelas on Exam
On exam, there is a large,
shiny erythematous plaque
with ill defined borders
located on the posterior
thigh
Cellultis and Erysipelas: Treatment
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Cellulitis and erysipelas are similar diseases and are
treated similarly with:
 Empiric IV antibiotics to cover Strep and Staph
 If there is no response, one may consider MRSA
as the possible cause and change antibiotics
appropriately
 Draw blood cultures to assess for sepsis
Elevation on the involved area
 Treat tinea pedis if present as it may be the portal of
entry for >80% of cellulitis cases
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17
Case 2
Case 2: History
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HPI: A 58 yo male who had a total hip replacement 2
days ago and is now on the surgery floor recovering is
found to have redness of his left leg. He states that the
leg is painful but does not itch.
PMH: left hip replacement 2 days ago
All: none
Meds: lisinopril, atenolol, glyburide
FH: non-remarkable
SH: lives in the city with his wife and children. Patient
denies alcohol, smoking, or IV drug use
ROS: +fever
Case 2: Exam
On exam,
VS: T-102.1, HR-110, BP90/50, RR-18, O2sat 98%
Gen: ill appearing
Skin: large erythematous
plaque with central patches
of dusky blue discoloration
20
Case 2: Question 1
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What is the most likely diagnosis?
a. cellulitis
b. tinea corporis
c. necrotizing fasciitis
d. erysipelas
Case 2: Question 1
Answer: c
 What is the most likely diagnosis?
a. cellulitis (would expect more erythema and
less dusky blue discoloration)
b. tinea corporis (would not expect patient to be
so systemically ill and would expect pruritus)
c. necrotizing fasciitis
d. erysipelas (would expect more erythema and
less dusky blue discoloration)
Diagnosis: Necrotizing Fasciitis
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Necrotizing fasciitis is a serious infection of the fascia
just above the muscle
It progresses rapidly over the course of days and may
follow surgery or trauma, or have no preceding visible
lesion
It can be caused by group A strep, staph or a variety of
other organisms
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At times, it can be associated with Toxic Shock
It is considered a MEDICAL/SURGICAL
EMERGENCY with up to a 20% fatality rate!
Necrotizing Fasciitis on Exam
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On exam, one sees an expanding dusky, swollen, red
plaque with blue discoloration
 It may turn purple and blister
 Anesthesia may develop on the skin of the affected
area
The infection typically spreads rapidly over the course
of hours to days
Poor prognostic factors include: age>50, diabetes,
atherosclerosis, 7 day delay in diagnosis, infection
involving the trunk
Necrotizing Fasciitis: Work up and
Treatment
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In cases of necrotizing fasciitis, it is most important
to diagnose and treat IMMEDIATELY!
An MRI can assist in diagnosing necrotizing fasciitis
Diagnosis is confirmed by a deep biopsy in the OR
TREATMENT: WIDESPREAD
DEBRIDEMENT AND IV ANTIBIOTICS
Case 3
Case 3: History
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HPI: 74 yo woman presents with a rash on her leg that
has been present for 3 months. She does not have any
pain in her legs but does not some itch. She has not
used any medications for this rash.
PMH: diabetes, HTN
All: none
Meds: lisinopril, metoprolol, glyburide
FH: non-remarkable
SH: lives with her husband in the city. Has been
overweight throughout her life
ROS: +pruritus
Case 3: Exam
On exam,
VS: non-remarkable
Gen: well appearing,
overweight woman in NAD
Skin: erythematous brown
hyperpigmented plaque with
fine fissuring and scale located
above the medial malleolus on
the left lower leg
Case 3: Question 1
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What is the most likely diagnosis?
a. cellulitis
b. erysipelas
c. stasis dermatitis
d. tinea corporis
e. atopic dermatitis
Case 3: Question 1
Answer: c
 What is the most likely diagnosis?
a. cellulitis (would expect fever without scale or
pruritus)
b. erysipelas (see above)
c. stasis dermatitis
d. tinea corporis (would have a more defined border
and be erythematous)
e. atopic dermatitis (incorrect distribution and age
group)
Diagnosis: Stasis Dermatitis
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Stasis dermatitis is the most commonly missed
diagnosis when evaluating a patient with a red leg!
It results from inadequate function of the venous
system due to anatomic abnormalities (loss of
valves, perforators, congenital abnormalities)
 Over time, valves age and for this reason older
patients tend to have stasis dermatitis more
commonly.
Stasis Dermatitis on Exam
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Stasis dermatitis typically presents as erythematous plaques
with fine fissuring and a yellowish or light brown
hyperpigmentation located superior to the medial malleolus
 May have an associated dermatitis with weeping, scale,
or lichenification
 Patient may have a red, hot, swollen leg in the
ABSENCE of fever, leukocytosis, LAD, or streaking
On exam, edema is often present, as well as varicose veins
and hemosiderin deposits
 Hemosiderin: Pinpoint yellow-brown macules and
papules
Stasis Dermatitis on Exam
On exam,
There is a large
erythematous plaque with
fine fissuring and scale as
well as interspersed
brown macular
hyperpigmentation
Pinpoint brown
macule (hemosiderin)
Stasis Dermatitis: Complications
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Stasis dermatitis can be complicated
by a number of conditions:
 Cellulitis
 Ulceration
 Contact dermatitis
 Eczematous dermatitis
It can also lead to to fat necrosis
(sclerotic panniculitis/
lipodermatosclerosis) with the end
stage being permanent sclerosis
(lipodermatosclerosis) with “inverted
champagne bottle” legs as seen here
Stasis Dermatitis: Complications
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Stasis dermatitis is a chronic condition
and may result in many bouts of
cellulitis. This may result in lymphatic
insufficiency.
 The recurrent infection, usually in
the setting of obesity, results in
edema that becomes firm (nonpitting)
The overlying skin becomes pebbly,
hyperkeratotic and rough (elephantiasis
verrucosa nostra = lymphostasis
verrucosa cutis)
Ulceration in this setting (with lymphatic
and venous insufficiency) is significantly
harder to treat and heal
Stasis Dermatitis: Diagnosis
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Venous Rheography is a non-invasive study using light reflection
to assess for venous insufficiency. It is often helpful
 Visual inspection is a very poor indicator of venous
competence of the lower leg
If peripheral pulses are diminished or leg hair is absent this may
suggest underlying arterial insufficiency making ABI
(ankle/brachial index) an important study
 ABI = systolic blood pressure of the leg/systolic blood
pressure of the arm (put in normal range) which indicates the
degree of limb ischemia
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Normal Range: 1-1.3 (greater than 1.3 suggests arterial calcification)
Claudication Range: 0.5-0.9 (pain from ischemia with activity)
Severe Range: <0.5 is referred to surgery (<0.3 can result in rest ischemia and
gangrene)
Stasis Dermatitis: Treatment
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When considering the treatment of stasis dermatitis it is
important to treat both the eczematous symptoms as well as
the underlying venous insufficiency
 Application of super-high and high potency steroids to
area of dermatitis under the wrap
 Elevation (to reduce edema)
 Unna boot wrapping with Coban or Profore (4 layer wrap)
 Unna boot is a special gauze used for stasis dermatitis
and ulcers
 Ace bandage compression
 Change wraps weekly, or more often if the lesion is very
weepy
Compression Therapy is Effective!
PRIOR TO TREATMENT
FOLLOWING TREATMENT
Case 4
Case 4: History
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HPI: A 65 year old female complains of one week of a itchy
rash on her right leg. She states that she otherwise feels
well. She returned from a camping trip two weeks ago. She
has never had anything like this before.
PMH: none
All: none
Meds: none
FH: non-remarkable
SH: lives in the city with her husband. Denies alcohol,
smoking, IV drug use
ROS: negative
Case 4: Exam
On exam,
VS: afebrile
Gen: well appearing in NAD
Skin: erythematous plaque located
on the medial right leg with
erosions.
Case 4: Question 1
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What is the most likely diagnosis?
a. cellulitis
b. necrotizing fasciitis
c. vasculitis
d. contact dermatitis
Case 4: Question 1
Answer: d
 What is the most likely diagnosis?
a. cellulitis (would expect fever)
b. necrotizing fasciitis (would expect fever and
systemic illness)
c. vasculitis (would expect purpura)
d. contact dermatitis
Contact Dermatitis
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Contact dermatitis comes in two varieties
 Irritant dermatitis – will cause symptoms in most people.
Symptoms occur without previous exposure.
 More common than allergic contact dermatitis and
can result from a variety of chemicals
 Allergic contact dermatitis – will only affect those with a
sensitivity. Symptoms are delayed for hours-days after
exposure. CHARACTERIZED BY ITCH
In this case, the patient had allergic contact dermatitis as
evidenced by her symptoms taking time to develop
following her exposure (camping trip)
Allergic Contact Dermatitis: Presentation
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In allergic contact dermatitis, the lesion appears
erythematous, edematous, and often blistered
The initial outbreak typically occurs 7-10 days
after exposure
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Subsequent outbreaks may appear within hours of
exposure and usually within 2 days
The patient typically appears well with no fever
or elevated WBC count
Allergic Contact Dermatitis: Causes
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There are a number of causes of allergic contact dermatitis
including:
 Rhus dermatitis (poison oak, poison ivy, poison sumac
all contain urushiol)
 Topical medications neomycin and bacitracin
(reason to use polysporin)
 Nickel
 Rubber
 Gold
 Formaldehyde
 Thimerosal
Contact Dermatitis Treatment
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Treatment involves both the removal of the
causal agent as well as topical corticosteroids
Case 5
Case 5: History
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HPI: 58 yo woman is in the hospital after having had a
kidney transplant two months ago. Over the past few
weeks she notes a worsening itchy rash on her legs.
She has never had anything like it before
PMH: diabetes, renal failure
All: hay fever
Meds: cyclosporine, oral prednisone, insulin
FH: non-remarkable
SH: lives at home with her husband and 2 children
ROS: negative
Case 5: Exam
On exam,
VS: afebrile
Gen: well appearing, NAD
Skin: large erythematous
annular plaque with a raised
scaly border
Case 5: Question 1
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Which is the most appropriate study to perform
at this point?
a. deep punch biopsy
b. debridement
c. IV antibiotics
d. KOH prep
e. MRI to assess for depth of involvement
Case 5: Question 1
Answer: d
 Which is the most appropriate study to perform
at this point?
a. deep punch biopsy
b. debridement
c. IV antibiotics
d. KOH prep
e. MRI to assess for depth of involvement
Case 5: KOH Results
Hyphae seen on
KOH prep
KOH FINDINGS CONFIRM
THAT THE DIAGNOSIS IS A
FUNGAL INFECTION IN THIS
CASE TINEA CORPORIS
Diagnosis: Tinea Corporis
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Tinea corporis is an infection caused by a dermatophyte and
diagnosed by +KOH
 Fungal infections are named based on their location on the
body. In this case tinea corporis as the infection is
involving the body
 Other locations are tinea pedis (foot) and tinea capitis
(head)
Tinea corporis often takes weeks or months to develop and
when found on the leg as in this case it may originate from
tinea pedis or tinea cruris (groin)
 In this case, the patient’s immunosuppression allowed for a
more severe case
Tinea Corporis: Clinical Features
The following are typical findings
as demonstrated by the image on
the left
 Annular erythematous plaques
 Edges of plaques are often
serpiginous
 Overlying scale
 Advancing scaly border
 Clearing in the center of the plaques
Tinea Corporis: Treatment
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The mainstay of treatment is topical antifungal
medications
However, in severe cases such as the one in
Case 5, systemic anti-fungals become necessary
Other Causes of Red
Leg
Pigmented Purpuric Eruption
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1-3 cm patch/plaques on the lower
leg
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Confluent tiny papules with
hemorrhage
Brown-yellow hyperpigmentation
due to iron deposition
Location: Pretibial
Chronic, benign condition
Favors elderly men
May be pruritic or asymptomatic
Starts distally, with slow, chronic
proximal progression
Asteatotic Dermatitis (Xerotic Eczema)
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Caused by the loss of the epidermal water
barrier
More common in the elderly
Worsened by hot showers, deodorant soaps
Worse in the winter (dry, heated air)
Worse after ski trips (altitude, cold)
Asteatotic Dermatitis (Xerotic Eczema)
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Affects lower legs, flanks, arms
Spares armpits, groin, face
First stage:
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Second stage:
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flaking of the skin, pruritic
cracking of the skin looking like the
bed of a dry lake
itchy and stings
Third stage:
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Weepy dermatitis, ITCHY
Asteatotic Dermatitis on Exam
Erythematous patch with dry
scaling and cracking as well
as scattered excoriated
papules
Asteatotic Dermatitis: Diagnosis
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Diagnostic Pearl:
Itching is relieved by prolonged submersion in bath
(20-30 minutes)
 The itching then begins again 5-30 minutes after
getting out of the water
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Asteatotic Dermatitis: Treatment
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Moisturize
Soap to the axillae, groin, scalp only
Medium potency topical steroid (TAC) ointment
to the areas of redness and itch
Severe cases, soak in tub 20 minutes, apply TAC
ointment, cover with Saran Wrap and sleep in it
Summary: Causes of a Red Leg
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Cellulitis/erysipelas
Necrotizing fasciitis
Stasis dermatitis
Vasculitis
Pigmented purpuric dermatosis
Asteatotic dermatitis
Tinea Corporis
Contact dermatitis
Take Home Point: Distinguishing Cellulitis
Fever
Pain
Warmth
Bilateral
Streaking
Lymphadenopathy
Elevated
WBC
Cellulitis
Yes
Yes
Yes
Almost
never
Yes
Yes
Yes
Consider
another
diagnosis
No
+/-
+/-
often
No
No
No
END OF MODULE
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The Red Leg - Dermatology

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