Skin Infections

1
Skin Infections

• 13th April 2011
• Dr Samantha Triggs GPVTS ST2

2

• Bacterial skin infections
• Viral skin infections
• Fungal skin infections

3
Bacterial skin infections
4
Why does skin get infected?

• 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???

5

• 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

6
Case History 1

• A mother brings 5 yr old Johnny to surgery. He
  has developed this rash, which is weeping and
  crusting.

7

• What is the diagnosis?

8
Impetigo

• A highly infectious skin disease, which commonly
  occurs in children.

9

• What is the likely causative organism?

10

• The causative organism is usually Staphylococcus
  Aureus (gt90 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

11

• What is the treatment?

12
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)

13
Johnnys 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.

14
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

15

• What is the Diagnosis?

16
Folliculitis

• 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.

17

• What is the causative organism?

18

• 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)

19

• What is the treatment?

20
Folliculitis treatment

• 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

21
Cellulitis

• 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

22
Erysipelas
23

• What is the most common causative organsism?

24
Cellulitis

• 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)

25
Treatment of cellulitis

• 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

26
Orbital cellulitis refer urgently
27
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
28

• Diagnosis???

29
Staphylococcal Scalded Skin Syndrome

• 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

30

• 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

31

• Complications include hypothermia, dehydration
  and secondary infection.
• Treatment ABC, refer urgently for IV antibiotics
  and fluids, may need referral to tertiary burns
  centre

32
What is the diagnosis?
Painful red nodule
33
Furunculosis (boils) and carbuncles

• 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

34
What is the diagnosis?
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.
35
(No Transcript)
36
Necrotising Fasciitis

• 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

37
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.

38

• What is the diagnosis?

39
Pitted Keratolysis

• 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
• Breathable footwear
• Topical antibiotics (fusidin or mupirocin)
• Potassium permanganate, 20 aluminium chloride
  hexahydrate or 4 formaldehyde soaks can be
  affective

40
Case History 6

• Mr Smith is 40 yrs old who has a rash in his
  axilla.

41

• You are fortunate enough to have a woods light
  available in the room in your training practice!
• When you use the Woods light, the skin lesion
  shows a dramatic coral pink fluorescence.

42
Erythrasma

• 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

43
Viral Skin Infections
44
Viral warts and verrucas

• Caused by human papilloma virus
• Very common
• Disappear spontaneously eventually
• If treatment is needed, options include
• Salicylic acid topically needs daily treatment
  and can take months
• Duct tape occlusion
• Cryotherapy

45
Case history 7

• A father brings his 3year old Daughter Sarah to
  surgery. She has developed an itchy rash

46

• Diagnosis?

47
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

48
Molluscum contagiosum

• 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
• Piercing the lesion with an orange stick tipped
  with iodine
• Curretage
• imiquimod cream

49
Herpes Zoster (Shingles )

• 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

50

• 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

51
Shingles treatment

• Aciclovir 800mg 5 times daily, for 7 days
• Rest, analgesia
• Complications include
• Post herpetic neuralgia
• Secondary infection
• Guillain Barre Syndrome
• Occular disease

52
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

53
Herpes Simplex Virus

• True or false
• HSV 1 is commonly sexually transmitted
• The correct dose of aciclovir for HSV is 200mg 5
  times daily for 5 days
• Caesarean section should be recommended to all
  women presenting with primary episode genital
  herpes lesions at the time of delivery
• Caesarean section is routinely recommended for
  women with recurrent genital herpes lesions at
  the onset of labour.

54
Herpes Simplex Virus

• 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.

55
Types
Genital herpes
Herpetic Whitlow
Eczema Herpeticum
Herpes Simplex Keratitis
56
Fungal Infections
57
Diagnosis?
58
Dermatophyte infections

• 3 main genera
• Trichophyton
• Microsporum
• Epidermophyton
• Invade the keratin of the stratum corneum
• Can be
• 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

59
Name the fungus!!!
60
Tinea Corporis - Presents as scaly erythematous
plaques with central clearing
61
Tinea Cruris commoner in males, assymmetrical
erythema spreading from groin to upper thigh.
Scaly advancing edge.
62

• Tinea Pedis 2 main presentations
• - Moist scaling between the toes, esp 4/5
  webspace.
• - Mocassin type fine, dry diffuse scaling over
  the whole sole.

63
Tinea Manuum diffuse dry scaling over the palm
64
Tinea Capitis commonest in children. Presents
as non-itchy patches of hair loss with broken
hairs.
65
Tinea Unguium Different presentation
including - White Onchomycosis - Oncholysis -
Sub-ungural hyperkeratosis - Thickening of nail
plate
66
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.

67
Choose the diagnosis from the list below

1. Tinea Corporis
2. Lymes Disease
3. Psoriasis
4. Pityriasis Versicolor
5. Vitiligo

68
Pityriasis Versicolor

• 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

69
Candida

• A commensal organism which becomes pathogenic
  under certain circumstances
• 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

70

• Any Questions????

71
References

• 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