Download Skin Infections

Skin Infections
Omar Y. Abdullah
Bacterial skin
infections
Why does skin get infected?
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There are multiple types of bacteria which are
normally present on the skin.
For example: Staphylococcus epidermidis and
yeasts
The presence of bacteria does not automatically
lead to a skin infection
What is the difference between colonisation and
infections???
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Colonisation: Bacteria are present, but
causing no harm
Infection: Bacteria are present and
causing harm.
A break in the epidermal integrity can allow
organisms to enter and become
pathogenic. This can occur as a result of
trauma, ulceration, fungal infection, skin
disease such as eczema
Impetigo
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A highly infectious skin disease, which
commonly occurs in children.
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The causative organism is usually Staphylococcus
Aureus (>90% cases1), but less often can be strep
pyogenes.
Begins as a vesicle, which may enlarge into a
bulla.
Weeping, exudative area with characteristic honey
coloured or golden, gummy crusts, which leave
denuded red areas when removed.
Usually on the face around the mouth, but any
area could be affected.
Impetigo
Treatment:
 Mild localised cases - use topical antibiotic
Polyfax
 Widespread or more severe infections –
use systemic antibiotics, such as
flucloxacillin (or erythromycin if penicillin
allergic)
Folliculitis
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Inflammation of the
hair follicle.
Presents as itchy or
tender papules and
pustules at the
follicular openings.
Complications include
abscess formation
and cavernous sinus
thrombosis if upper
lip, nose or eye
affected.A
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Most common cause is Staph Aureus.
Other organisms to consider include:
Gram negative bacteria – usually in
patients with acne who are on broad spec
antibiotics
Pseudomonas (“Hot tub folliculitis”)
Yeasts (candida and pityrosporum)
Folliculitis treatment
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Topical antiseptics such as Chlorhexidine
Topical antibiotics, such as Fusidic acid or
Mupirocin
More resistant cases may need oral
antibioics such as Flucloxacillin
Hot tub folliculitis – ciprofloxacin
Gram negative – trimethoprim
Cellulitis
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Infection of the deep
subcutaneous layer of the skin
Presents as a hot, tender area
of confluent erythema of the
skin
Can cause systemic infection
with fever, headache and
vomiting.
Erysipelas is more superficial
and has a more well demarcated
border
Erysipelas
Cellulitis
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Streptococcus – Group A Strep Pyogenes.
Others include Group B, C, D strep,
Staphylococcus Aureus, haemophilus
influenzae (children) and anaerobic
bacteria (e.g Pasteurella spp. After animal
bites)
Treatment of cellulitis
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Oral Flucloxacillin or erythromycin if allergic
Co-amoxiclav in facial cellulitis
If severe systemic upset, may require admission
for IV antibiotics.
After the acute attack has settled, especially in
recurrent episodes – consider the underlying
cause
Orbital cellulitis – refer urgently
Staphylococcal Scalded Skin
Syndrome
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A superficial blistering condition
caused by exfoliative toxins of
certain strains of Staph Aureus
Usually in children less than 5 yrs
old
Characterised by blistering and
desquamation of the skin and
Nikolsky's sign (shearing of the
epidermis with gentle pressure),
even in areas that are not obviously
affected
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begins with a prodrome of
pyrexia and malaise, often
with signs and symptoms of
an upper respiratory tract
infection
discrete erythematous areas
then develop and rapidly
enlarge and coalesce,
leading to generalised
erythema - often worse in
the flexures with sparing of
the mucous membranes
large, fragile bullae form in
the erythematous areas and
then rupture
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Complications include
hypothermia, dehydration
and secondary infection.
Treatment: ABC, refer
urgently for IV antibiotics
and fluids, may need
referral to tertiary burns
centre
What is the diagnosis?
Painful red nodule
Furunculosis (boils) and carbuncles
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Deeper Staphylococcal abscess of the hair
follicle
Coalescence of boils leads to the
formation of a carbuncle
Treatment is with systemic antibiotics and
may need incision and drainage.
Consider looking for underlying causes,
such as diabetes
Erythrasma
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Colonisation of axillae or groin with
Corynebacterium Minutissimum.
Presents as a fine, reddish brown rash in the
flexures, which is sharply marginated.
Often misdiagnosed as a fungal infection
Woods light illumination produces a
characteristic coral-pink fluorescence.
Treatment is with topical fusidin cream.
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When you use the Wood’s light, the skin lesion
shows a dramatic coral pink fluorescence.
Viral Skin
Infections
Viral warts and verrucas
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Caused by human papilloma virus
Main types, common, plane and plantar
Very common
Disappear spontaneously eventually
If treatment is needed, options include:
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Salicylic acid topically – needs daily treatment and can
take months
Cryotherapy
Imiquimod cream
Molluscum contagiosum
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Caused by DNA pox virus
Common in children, but can occur at any age
Spread by direct contact
Presents as multiple small, pearly, dome-shaped papules
with central umbilication
Can occur at any site
Usually resolve spontaneously in 6-18 months
Resolution is heralded by the development of erythema
around the lesions.
Treatment is not usually necessary – simple reassurance
and advice about reducing transmission.
If treatment is necessary, options include:
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Piercing the lesion with an orange stick tipped with iodine
Curretage
imiquimod cream
Herpes Zoster (Shingles )
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Caused by reactivation of the chickenpox virus
which has lain dormant in the dorsal root or
cranial nerve ganglia
Rash is preceded by a prodromal phase of up
to 5 days of tingling or pain
Then develop painful grouped
vesicles/pustules on a red base in a
dermatomal distribution.
Most common in thoracic and trigeminal areas
Lesions become purulent, then crusted
Healing takes place in 3-4 weeks
Shingles treatment
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Aciclovir 800mg 5 times daily, for 7 days
Rest, analgesia
Complications include:
 Post herpetic neuralgia
 Secondary infection
 Guillain Barre Syndrome
 Occular disease
Post-herpetic Neuralgia
Pain lasting longer than 3 months after the
rash.
The followings are risk factors for
developing post-herpetic neuralgia?
A: Older age
B: More severe pain during the eruption
C: Severely inflamed rash
D: Prodromal pain in dermatome
Herpes Simplex Virus
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A highly contagious infection spread by direct
contact
HSV 1 : also commonly called “coldsore”
HSV 2 usually presents on the genitalia
Primary infection is usually asymptomatic.
Recuurent infection presents as acute, painful
gingivo-stomatitis with multiple small intra/perioral ulcers (but any site could be affected).
Associated with fever, malaise and
lymphadenopathy.
Genital herpes
Herpes Simplex Keratitis
Herpetic Whitlow
Clinically: Grouped umbilicated
vesicles/pustules on erythematous base.
Treatment:
 Topical aciclovir can be used: 5 times daily
for 5 days. Reduces duration of attack and
duration of viral shedding.
 The correct dose of aciclovir for HSV is
200mg 5 times daily for 5 days
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Thank you