Download Skin Infections - Derby GP Specialty Training Programme

Skin Infections
13th April 2011
Dr Samantha Triggs GPVTS ST2
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Bacterial skin infections
Viral skin infections
Fungal skin infections
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
Case History 1
A mother brings 5 yr old
Johnny to surgery. He
has developed this
rash, which is
weeping and crusting.
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What is the diagnosis?
Impetigo
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A highly infectious skin disease, which
commonly occurs in children.
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What is the likely causative organism?
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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.
May present as macules, vesicles, bullae or
pustules
Bullae are more prominent in staphylococcal
infection and in infants
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What is the treatment?
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)
Johnny’s mum asks if Johnny has to have
any time of off school.
What should you tell her?
A: He does not have to be excluded from school so
long as he is on antibiotics
B: He has to remain off of school for 5 days from
the onset of the lesions
C: He must remain off of school until the lesions
have crusted or healed
D: He must remain off of school until he has
completed the antibiotic course.
Case History 2
A 27 year old business
man attends surgery
complaining of pain
and itching in the
beard area. You
examine him and see
the following:
What is the Diagnosis?
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.
What is the causative organism?
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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)
What is the treatment?
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 – ciprofloxacin2
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
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What is the most common causative
organsism?
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
Case History 3
A mother phones the surgery about her 1 year old
daughter Emma. Emma has been off her food
and has had a slight runny nose. She has
developed an erythematous rash. You arrange for
her to attend the surgery for an appointment
When Emma is seen in the surgery, the rash has started
to spread, now there is superficial blistering and parts of
the epidermis can be seen to shear off after gentle
pressure
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Diagnosis???
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
Case history 4
Mrs. Brown is a 78 yrs old type 2 diabetic.
Mr Brown phones the surgery to request a home visit for his
wife. He tells you that Mrs Brown has been feeling unwell for
a few days with a pyrexia and headache. She has a red
area of skin on her lower leg which is intensely painful.
You arrange a home visit.
When you arrive, Mrs Brown is quite lethargic and confused.
Temp 39 degrees
HR 115 bpm
BP 90/50
You notice that the edge of the area starts to become purple.
What is the diagnosis?
Necrotising Fasciitis
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Rare, but serious and fatal condition
Deep-seated infection of subcut fat and
fascia which spreads along fascial planes.
Vascular thrombosis leads to rapidly
progressing infarction and death of skin and
tissue, with systemic infection
If suspected – refer urgently
Case history 5
Mr Jones is a 22 year old
who works as a personal
trainer. He attends
surgery as he wants to
discuss his smelly feet!
He tells you he has
developed lots of “holes”
in the soles of his feet.
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What is the diagnosis?
Pitted Keratolysis
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Caused by Cornebacteria, which colonise the surface
stratum corneum and produce areas of sharply demarcated
maceration.
Later develops a characteristic pitted appearance.
Smells like rotten fish
More common in young males, who wear tight occlusive
shoes
Treatment is aimed at reducing sweating and reducing
bacterial colonisation:
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Breathable footwear
Topical antibiotics (fusidin or mupirocin)
Potassium permanganate, 20% aluminium chloride hexahydrate or
4% formaldehyde soaks can be affective
Case History 6
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Mr Smith is 40 yrs old who has a rash in
his axilla.
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You are fortunate enough to have a wood’s
light available in the room in your training
practice!
When you use the Wood’s light, the skin lesion
shows a dramatic coral pink fluorescence.
Erythrasma
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Colonisation of axillae or groin with
Cornebacterium Minutissimum.
Presents as a fine, reddish brown rash in the
flexures, which is confluent and sharply
marginated.
Often misdiagnosed as a fungal infection
Woods light illumination produces a
characteristic coral-pink fluorescence.
Treatment is with topical fusidin cream
Viral Skin Infections
Viral warts and verrucas
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Caused by human papilloma virus
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
Duct tape occlusion
Cryotherapy
Case history 7
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A father brings his 3year old Daughter
“Sarah” to surgery. She has developed an
itchy rash:
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Diagnosis?
Molluscum Contagiosum
Which one of the following statements regarding
this condition is incorrect?
A: Usually spontaneously resolves
B: Caused by an RNA pox virus
C: Transmission is by direct contact
D: There is no need for school exclusion
E: Lesions usually heal without scarring
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 vesicles in a
dermatomal distribution. Most common in
thoracic and trigeminal areas
Lesions become purulent, then crusted
Healing takes place in 3-4 weeks
Regarding infectivity and shingles: true or false?
1. Children with shingles should remain off
school from 5 days from the onset of rash
2. Shingles in a pregnant mother does not carry
a risk of her own fetus developing fetal
varicella syndrome.
3. You can catch shingles from another person
who has shingles
4. If not immune, you can catch Chicken Pox
after contact with shingles
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.
Which of the following is NOT a risk factor
for developing post-herpetic neuralgia?
A: Younger age
B: More severe pain
C: Severe rash
D: Prodromal pain in dermatome
Herpes Simplex Virus
True or false:
1.
HSV 1 is commonly sexually transmitted
2.
The correct dose of aciclovir for HSV is 200mg 5
times daily for 5 days
3.
Caesarean section should be recommended to all
women presenting with primary episode genital
herpes lesions at the time of delivery
4.
Caesarean section is routinely recommended for
women with recurrent genital herpes lesions at
the onset of labour.
Herpes Simplex Virus
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A highly contagious infection spread by direct
contact
HSV 1 = common coldsore
HSV 2 usually presents on the genitalia
Primary infection presents as acute, painful
gingivo-stomatitis with multiple small intra-oral
ulcers. Associated with fever, malaise and
lymphadenopathy.
Attacks are usually self-limiting
Topical aciclovir can be used for oral lesions: 5
times daily for 5 days. Reduces duration of
attack and duration of viral shedding.
Types:
Genital herpes
Herpetic Whitlow
Herpes Simplex Keratitis
Eczema Herpeticum
Fungal Infections
Diagnosis?
Dermatophyte infections
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3 main genera:
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Trichophyton
Microsporum
Epidermophyton
Invade the keratin of the stratum corneum
Can be:
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Anthopophilic – contracted from humans
Zoophilic – contracted from animals
Geographic – contracted from soil
Clinical appearance depends on the organism involved, the site and
the host reaction
Name the fungus!!!
Tinea Corporis - Presents as scaly
erythematous plaques with central clearing
Tinea Cruris – commoner in
males, assymmetrical erythema
spreading from groin to upper
thigh. Scaly advancing edge.
Tinea Pedis: 2 main presentations:
- Moist scaling between the toes, esp 4/5 webspace.
- Mocassin type – fine, dry diffuse scaling over the whole
sole.
Tinea Manuum – diffuse dry scaling over the palm
Tinea Capitis – commonest in children.
Presents as non-itchy patches of hair loss
with broken hairs.
Tinea Unguium – Different presentation
including:
- White Onchomycosis
- Oncholysis
- Sub-ungural hyperkeratosis
- Thickening of nail plate
Case History 8
A 22 year old lady returns from a holiday in
Spain. She has a tan. She has noticed
hypopigmented lesions on her chest and back.
Choose the diagnosis from the list
below
1.
2.
3.
4.
5.
Tinea Corporis
Lyme’s Disease
Psoriasis
Pityriasis Versicolor
Vitiligo
Pityriasis Versicolor
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Common in young adults
Occurs when the commensal follicular
yeast Pityrosporum Orbiculare transforms
into a mycelial form.
Presents as fine, reddish-brown, scaly
eruptions which are asymptomatic.
Once the rash has gone, it leaves
hypopigmented macules which fail to tan
Treat with topical imidazole cream if fine
scaling present
Candida
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A commensal organism which becomes pathogenic under
certain circumstances:
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With broad spec antibiotic use
Pregnancy
Immuno-compromise and diabetes
Moist skin folds and areas of damp skin
Can present at various sites, including orally, in genitals,
groin, under breasts
Management:
 drying affected area,removing causative factors.
 topical antifungal creams
Any Questions????
References
1.
2.
3.
4.
Kumar and Clark: clinical medicine 5th
Edition.
General Practice Notebook
www.GPnotebook.co.uk
RCOG Greentop guideline number 30:
Genital Herpes in pregnancy
Practical General Practice