Cutaneous Anthrax

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Cutaneous Anthrax
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• Mimics
• Ecthyma
• Brown Recluse Spider Bite
• Acute Febrile Neutrophilic Dermatosis
• (Sweet's Syndrome)
• Folliculitis, Furuncle, Carbuncle, Cutaneous
  Abscess
• Pyoderma Gangrenosum
• Orf Virus Infection

Variola (Smallpox)
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• Mimics
• Varicella (Chickenpox)
• Herpes Zoster (Shingles)
• Molluscum Contagiosum

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Cutaneous Anthrax
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3
Variola (Smallpox)
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4
Cutaneous Anthrax
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The primary lesion of cutaneous anthrax is a
painless, pruritic papule that appears one to
seven days after inoculation. Within one to two
days, small vesicles or a larger, 1- to 2-cm
vesicle forms that is filled with clear or
serosanguineous fluid. As the vesicle enlarges,
satellite vesicles may form.
Fitzpatricks Dermatology in General Medicine.
Fifth Edition. Freedberk IM, Eizen, AZ, Wolff, K,
Austen KF, Goldsmith LA, Katz SI, Fitzpatrick TB
(eds.). New York The McGraw Hill Companies, Inc
1999.
Fluid within the vesicles may contain numerous,
large gram-positive bacilli. As the lesion
matures, a prominent, non-pitting edema surrounds
it. Eventually, the vesicle ruptures, undergoes
necrosis, and enlarges, forming an ulcer covered
by the characteristic black eschar. Symptoms
include low-grade fever and malaise. Regional
lymphadenopathy is present early on.
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Ecthyma
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Ecthyma
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Ecthyma is a condition in which the exudate or
crust of a pyogenic infection involves the entire
epidermis. The crust can be thick and
adherent. Ecthyma is usually the consequence of
neglected impetigo caused by Staphylococcus
aureus or group A streptococcus. Ecthymatous
lesions can evolve from localized skin abscesses
(boils) or within sites of preexisting trauma.
The margin of the ecthyma ulcer can be indurated,
raised, and violaceous. Untreated ecthymatous
lesions can enlarge over the course of weeks or
months to a diameter of 2 to 3 cm.
Staphylococcal and streptococcal ecthyma occurs
most commonly on the lower extremities of
children, the elderly, and people who have
diabetes. Poor hygiene and neglect are key
elements in its pathogenesis. Ecthyma
gangrenosum is a cutaneous ulcer caused by
Pseudomonas aeruginosa it resembles ecthyma
caused by staphylococcal or streptococcal
organisms. Ecthyma gangrenosum, which usually
occurs in individuals with prolonged neutropenia,
can be associated with Pseudomonas bacteremia.
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Differential Dx - Ecthyma
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• Cutaneous anthrax
• Lesion located most commonly on upper
  extremities (especially the hands), neck, or face
• Systemic manifestations include fever, malaise,
  regional lymphadenopathy

• Ecthyma
• Lesions located most commonly on lower
  extremities
• Systemic symptoms unusual

• Ecthyma gangrenosum
• Associated with neutropenia
• May be associated with Pseudomonas bacteremia

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Brown Recluse Spider Bite
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Brown Recluse Spider Bite
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• The brown recluse spider, Loxosceles reclusa
• is widely distributed in the U.S. throughout the
  Southeast and Midwest
• natural habitat is outdoors under overhanging
  rocks and cliffs
• lives in closets, attics, and outbuildings
• hibernates during the winter, so most bites
  occur between March and October
• Responses to bites range from mild local
  urticarial (hive-like) reactions to
  full-thickness skin necrosis. The more extensive
  reactions may be associated with systemic
  manifestations including a maculopapular rash,
  fever, headache, malaise, joint aches, and nausea
  and vomiting.
• The bite itself is generally painless, and the
  findings of a central papule and associated
  redness may not be seen for 6 to 12 hours.

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Brown Recluse Spider Bite
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Only approximately 10 of bites progress to skin
necrosis those that do tend to show progression
in 48 to 72 hours. Central blistering with a
surrounding gray to purple discoloration at the
bite site may appear. The site is surrounded by a
ring of blanched skin that in turn is surrounded
by a large area of redness, producing the "red,
white, and blue" sign typical of a brown recluse
spider bite. At this stage, the bite is
associated with significant pain. As the wound
becomes necrotic, it will turn black. Healing is
slow and may require skin grafting to cover the
defect. Not all victims recall the spider bite,
and because the clinical appearance is
nonspecific, diagnosis can be difficult.
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Differential Dx Brown Recluse
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• Brown Recluse Spider Bite
• Bite lesion becomes painful
• Necrosis of skin and subcutaneous tissue occurs
  early and quickly

• Cutaneous anthrax
• Painless lesion
• Necrosis of skin and subcutaneous tissue occurs
  late and gradually

12
Acute Febrile Neutrophilic Dermatosis (Sweet's
Syndrome)
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13
Acute Febrile Neutrophilic Dermatosis (Sweet's
Syndrome)
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Acute febrile neutrophilic dermatosis, or Sweet's
syndrome, is characterized by the presence of
recurrent, painful, plaque-forming inflammatory
papules, and sometimes fever and systemic
leukocytosis. There is no known cause of
Sweet's syndrome. Approximately 20 percent of
cases are associated with malignancy. The
typical skin lesions are red or bluish-red
papules or nodules that tend to coalesce to form
irregular, sharply demarcated plaques. There is
an associated inflammatory edema within the
lesion that gives the illusion of vesicles on the
surface of the lesion. In later stages, the tops
of the papules may become studded with tiny
pustules.
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Acute Febrile Neutrophilic Dermatosis (Sweet's
Syndrome)
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The lesions of Sweet's syndrome are tender and
often painful, and are likely to enlarge over a
period of days to weeks. The presentation can
be a single lesion or multiple lesions. The
eruption occurs characteristically on the upper
extremities, face, or neck, but it can also
develop on the lower extremities. Systemic
symptoms can include fever and leukocytosis
patients can appear very ill. Not all patients
express the entire spectrum of findings, however,
and fever and leukocytosis may be absent. Other
symptoms may include headache, joint pain,
myalgias, and malaise.
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Differential Dx Sweets
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• Sweets Syndrome
• Multiple lesions most common
• Painful or tender lesions
• Edema within the lesions

• Cutaneous anthrax
• Solitary lesion
• Painless lesion
• Necrotic ulceration
• Formation of black eschar
• Characteristic massive edema surrounds the
  lesion

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Folliculitis, Furuncle, Carbuncle, and Cutaneous
Abscess
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Carbuncle on the back of the neck. Notice the
elevated red lesion with multiple draining
pustules.
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Folliculitis, Furuncle, Carbuncle, and Cutaneous
Abscess
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Folliculitis is characterized by the formation of
a circumscribed, conical pustule around a hair
follicle. A furuncle is a deep, necrotizing
form of folliculitis, with pus accumulation.
Several furuncles may coalesce to form a
carbuncle. An abscess (boil) is a localized
accumulation of purulent material deep in the
dermis or subcutaneous tissue. Pus may not be
visible on the surface of the skin. An abscess is
warm, red, and tender it frequently begins as
folliculitis. Most furuncles and carbuncles are
caused by Staphylococcus aureus. Fever and
malaise sometimes accompany carbuncles and
abscesses.
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Folliculitis, Furuncle, Carbuncle, and Cutaneous
Abscess
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A furuncle starts as a hard, tender, red nodule
in hair-bearing skin that enlarges and becomes
painful and fluctuant. Rupture may occur with
drainage of pus. The pain then subsides, and the
redness and swelling subside over several days or
weeks. A carbuncle is larger than a furuncle,
typically occurring at the nape of the neck or on
the back or thighs. The lesion is red, indurated,
painful, and multiple pustules soon appear on its
surface, draining around multiple hair follicles.
The lesion develops a yellow-gray crater at the
center and heals slowly by granulation.
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Differential Dx Folliculitis
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• Furuncles, carbuncles, and abscesses
• Painful lesion
• Pus-draining lesion surrounding hair follicle

• Cutaneous anthrax
• Painless lesion
• Lesion does not drain pus, is not necessarily
  associated with hair follicle
• Vesicle ulcerates and forms characteristic black
  eschar

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Pyoderma Gangrenosum
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21
Pyoderma Gangrenosum
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Pyoderma gangrenosum is a destructive,
inflammatory skin disease in which a painful
nodule or pustule breaks down to form a
progressively enlarging ulcer, with a raised,
tender, undermined border. Pyoderma gangrenosum
can sometimes occur in the presence of an
underlying systemic disorder such as ulcerative
colitis, Crohn's disease, arthritis, gammopathy,
or other conditions. The distinguishing feature
of pyoderma gangrenosum is an ulcer with a
raised, inflammatory border and a boggy, necrotic
base. It starts as a deep, painful nodule, or as
a superficial hemorrhagic pustule. The lesion
breaks down and ulcerates, discharging a
purulent, hemorrhagic exudate.
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Pyoderma Gangrenosum
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The border is irregular, elevated, and dusky-red
or purplish. A halo of bright erythema surrounds
the margin of an advancing ulcer. The base of
the ulcer is usually covered with necrotic
material and studded with small abscesses.
Lesions are often solitary, but may arise in
clusters and can involve any area of the
body. The onset of pyoderma can be explosive,
characterized by pain, toxicity, and fever, or
indolent and slow with massive granulation within
the ulcer, as well as crusting. Almost
invariably, the lesions are painful.
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Differential Dx Pyoderma Gangrenosum
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• Pyoderma Gangrenosum
• Painful lesion
• Purulent lesion

• Cutaneous anthrax
• Painless lesion
• Lesion associated with characteristic edema
• Forms an eschar

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Orf Virus Infection
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Orf virus is a member of the Poxviridae family.
It produces disease mainly among sheep, goats,
and musk oxen, but it can be transmitted to
humans. Farmers and veterinarians are among the
most likely to be exposed to the virus. The orf
lesion is approximately 1.5 cm in diameter, and
is usually a solitary lesion located on the
dorsal aspect of the finger. Regional
lymphadenopathy, lymphangitis, and fever are
common symptoms. The disease passes through
several distinct stages

• The lesion begins as a red, solid, elevated
  papule.
• It enlarges into a nodule with a red center,
  white middle ring, and red periphery (the target
  stage).
• In the acute stage, a red weeping surface is
  present.
• In the regenerative stage, a thin, dry crust
  develops, through which black dots may be seen
  covering the surface of the nodule.
• Small papillomas, or tiny growths, cover the
  surface.
• During the regressive phase, a thick crust
  develops over the surface of the lesion,
  papillomas decrease in size, and the lesion
  flattens out.

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Differential Dx Orf Virus
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• Orf Virus Infection
• Lesion forms crusts, scabbing

• Cutaneous anthrax
• Lesion forms black eschar surrounded by massive
  edema

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Variola (Smallpox)
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Smallpox in a man Notice the diffuse and
extensive distribution of lesions.
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Variola (Smallpox)
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Smallpox in a child Notice that all lesions are
in the same stage of development.
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Variola (Smallpox)
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• Smallpox is an acute exanthematous disease caused
  by infection with the poxvirus variola.
• The significant clinical features include
• Three-day prodromal illness characterized by
  fever, headache, backache, and vomiting.
• Generalized centrifugal rash that follows
• Begins centrally then spreads to the extremities
• Rapid succession of papules, vesicles, pustules,
  umbilication, and crusting over a 14-day period.
• Prior vaccination may alter the clinical
  presentation of smallpox. The following
  description applies to the classic presentation
  in unvaccinated individuals.

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Variola (Smallpox)
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A macular red rash may precede the appearance of
the papules, which are tense to palpation.
Papules soon vesiculate, forming a circumscribed,
elevated lesion that contains clear fluid. The
rash at this point can be very sparse, although
individual vesicles can coalesce to form large
patches. As the vesicles mature, they turn into
pustules. Central umbilication of the pustule is
characteristic of smallpox. Eventually, the
pustule crusts over and heals with scar
formation. A second important distinguishing
characteristic of smallpox is that all of the
lesions at a given time are in the same stage of
development. That is, at any one point in time
the lesions are all papules or vesicles or
pustules. Bacterial infection of the lesions can
occur, producing localized abscesses and
cellulitis.
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Varicella (Chickenpox)
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Chickenpox vesicle behind the ear. Notice the
translucent quality of the vesicle on the skin,
the classic "dew drop on a rose petal"
appearance.
Chickenpox on the palate. Notice the glistening,
water-drop characteristic of the chickenpox
vesicle on the palate.
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Varicella (Chickenpox)
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Chickenpox on the hand. Notice the simultaneous
occurrence of lesions in different stages of
development.
Chickenpox in an infant. Notice the rose-colored
macules, papules, vesicles, pustules, necrotic
pustules, and crusted lesions occurring
simultaneously.
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Varicella (Chickenpox)
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Varicella (chickenpox) and herpes zoster
(shingles) are distinct clinical entities cause
by the varicella-zoster virus (VZV). In young
children, prodromal symptoms of chickenpox are
uncommon, but in older children and adults, the
manifestation of the rash may be preceded by two
or three days of fever and chills, malaise,
headache, backache, sore throat, and dry
cough. The rash begins on the face and scalp and
spreads rapidly to the trunk, with relative
sparing of the extremities. New lesions arise in
crops, usually appearing centrally. Each crop
proceeds through the developmental phase
described below, so that at any given time, a
patient can have macules, papules, vesicles,
pustules, and crusts. In smallpox, by contrast,
at any given time, all lesions on the patient's
body are in the same phase of development.
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Varicella (Chickenpox)
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The first sign of chickenpox is rose-colored
macules that rapidly progress to papules then to
vesicles, then to pustules, and finally to
scabbing over with crusts. The typical wall of
the vesicle is so thin that it often resembles a
drop of water on the reddened surface of the skin
(the "dew drop on a rose petal" appearance). As
the lesion dries and changes from a vesicle to a
pustule, it umbilicates and then crusts over. The
crusts fall off in one to two weeks. Scarring
is rare unless the lesions become secondarily
infected vesicles can occur on the mucous
membranes, most commonly on the palate they can
also occur in the nose, pharynx, larynx, trachea,
gastrointestinal tract, conjunctiva, and vagina.
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Differential Dx - Chickenpox
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• Chickenpox
• Begins on the face and scalp, spreads to the
  trunk
• Lesions in various stages of development can
  simultaneously be present on the patient's skin

• Variola (Smallpox)
• Begins centrally, then spreads outward to face
  and extremities
• All lesions are always in a single stage of
  development

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Herpes Zoster (Shingles)
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Herpes (varicella) zoster on the arm. Notice the
characteristic grouping of vesicles
Varicella zoster on the face. Notice the
dermatomal distribution of the papules, vesicles,
and pustules.
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Herpes Zoster (Shingles)
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Herpes zoster is a localized disease caused by
the varicella-zoster virus (VZV). It is
characterized by unilateral radicular pain and a
vesicular eruption that is typically limited to
one or two dermatomes innervated by a spinal or
cranial nerve. The most distinctive
characteristics of herpes zoster are its
localization and it distribution, which is almost
always unilateral. The individual lesions of
varicella (chickenpox) and of zoster are
identical, but the lesions of zoster evolve more
slowly and are characterized by grouped vesicles.
The lesions of varicella, by contrast, are more
widely distributed. As in varicella, zoster
vesicles evolve into pustules, then dry and
crust.
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Differential Dx Herpes Zoster
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• Herpes Zoster (Shingles)
• Lesions are unilaterally distributed along a
  dermatome
• Lesions at any given time are in different
  stages of development (vesicles, pustules, and
  crusts are in evidence at one time)

• Variola (Smallpox)
• Lesions are widely distributed
• Lesions at any given time are all at the same
  stage of development
• Associated with severe constitutional symptoms

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Molluscum Contagiosum
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Molluscum contagiosum is a common, benign viral
infection of the skin and mucous membranes caused
by the molluscum contagiosum virus. It typically
affects children, but can be transmitted sexually
in adults. The mature lesion is an umbilicated
papule.
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Molluscum Contagiosum
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Lesions begin as small (3 to 6 mm) papules that
are smooth, flesh-colored domes with a central
dimple. Inside the papule is a white, curd-like
core that can be easily expressed. Lesions can
occur anywhere on the skin and mucous membranes,
but are usually grouped in one or two areas.
Occasionally, they may be widely disseminated.
Typically fewer than 20 lesions are present, but
some individuals may have hundreds. The head,
eyelids, trunk, and genitalia are most commonly
affected, the genitalia being the predominant
site in adults. The lesions are
characteristically asymptomatic, but a few
patients may complain of itching or may develop
an eczematous reaction around the lesions.
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Differential Dx Molluscum Contagiosum
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• Molluscum Contagiosum
• Lesions usually grouped in one or two areas
• Not associated with clinical symptoms
• Lesions are papules only

• Variola (Smallpox)
• Lesions are widespread
• Associated with severe clinical symptoms
• Lesions progress from macules to vesicles to
  papules to crusts (progression occurs all at the
  same time in smallpox but at different times in
  chickenpox)

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