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Flashcards in Skin infections Deck (41)
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1

Where is Staphylococcus aureus often found?

As a skin commensal In skin infections

2

What are the the toxins sometimes produced by Staphylococcus aureus?

  • Panton Valentine Leuocidin (PVL)
  • Exfoliative toxin
  • TSST-1 (Toxic Shock Syndrome Toxin 1)
  • Enterotoxin

3

What happens in Staphylococcus aureus infections producing PVL?

Necrotising damage Much more serious infection

4

What is exfoliative toxin?

  • Produced in some Staphylococcus aureus infections
  • Targets the same antigens as in pempigus vulgaris (desmoglein 1 & 3) 

5

What kind of infections does staphylococcus aureus cause?

Skin Bone Joint Lung

6

What are the different skin infections of staphylococcus aureus?

  • Impetigo - subcorneal layer of epidermis
  • Folliculitis - mouth of the hair follicle
  • Ecthyma - full thickness of the epidermis and possibly the superficial dermis
  • Boil - abscess (pus filled inflammed area) of hair follicle
  • Carbuncle - Abscess of several adjacent hair follicles

7

What is very characteristic of Staphylococcus aureus skin infection?

Gold coloured crust

8

What does exfoliative toxin producing Staphylococcus aureus infections cause in adults?

Bullous impetigo

Cleavage of the skin in the epidermis above the BM

 

9

When does ecthyma often develop?

After insect bites

10

How is an abscess treated?

Incision and drainage of the abscess to let the puss out

11

What does exfoliative toxin producing Staphylococcus aureus infections cause in children?

  • Staphylococcal scalded skin syndrome
  • Only affects children under 5
  • Widespread erythema and exfoliation (to come off in scales/flakes) 

12

What is the treatment for Staphylococcus aureus infection?

  • Flucloxacillin
  • If MRSA - erythromycin or clarithromycin

13

What causes syphillis?

Treponema pallidum

A gram neagtive spirochaete

14

What increases your chance of getting syphilis?

It's an STD so sexual contact

Having other STDs esp HIV 

15

What are the stages of acquired Syphilis?

1. Primary (3-8 weeks)

  • Painless ulcer (chancre) at inoculation site
  • Heals up and disappears quickly

2. Secondary (6-12 weeks)

  • Disseminated to lymph nodes - lymphadenopathy
  • Generalised rash all over the body including palms and soles
  • Septicemia like symptoms
  • Axillary and groin warty lesions (condyloma lata - not actual warts)

3. Latent

4. Tertiary syphilis (years later)

  • Skin, neurological, bone and vascular (aortic aneurysms) manifestations

16

What does congenital syphilis cause?

  • Early and late miscarriages
  • Still births
  • Pre-maturity
  • Rashes
  • Brain and neurological problems
  • Bone disease

17

How is syphillis treated?

Screened before birth

Penicillin treatment very effective

18

What are the diseases caused by human herpes viruses 1-3 (HVVs)?

  • HVV1 -> HSV 1 -> Oro-genital herpes
  • HVV2 -> HSV 2 -> Oro-gential herpes
  • HVV3 -> varicella zoster (VZV) -> Chickenpox and shingles

19

What can re-activate latent HSV?

  • Stress
  • Poor sleep
  • Other illnesses
  • Sun exposure

20

What are the target cells and latency site for HVV 1-3?

  • Target cell - Muco-epithelial cells
  • Latency cells - neurones (dorsal root ganglion)

21

What are the clinical presentations of HSV?

  • Vesicular rash - 2 weeks
  • Pain before the appearance of the rash
  • Eczema herpeticum
  • Herpes encephalitis - inflammation of the brain causing focal neurology and reduced consciousness
  • Stomatitis - inflammation of mouth and lips

22

Generally, what type of herpes do HSV1 and HSV2 cause?

  • HSV1 - oral herpes
  • HSV2 - genital herpes

Note:

Not always the case, they can both cause both types, above is just the most common

23

Is the inital or subsequent HSV infections worse?

Initial can be much worse

24

Where is chicken pox focused?

  • Primarily on the face
  • Then body
  • Least on arms and legs

25

What is the outcome of a chicken pox infection?

  1. Usually resolves itself
  2. Rarely can cause:
  • pneumonia
  • encephalitis
  • death

26

What is the other name for shingles?

Herpes zoster

27

What can cause reactivation of varicella zoster?

Low immunity

28

Explain the presentation of herpes zoster?

  • Varicella zoster is latent in dorsal root ganglion
  • When reactivated it effects the dermatome of the nerve is was latent in
  • Inflammatory lesions along one dermatome 
  • Doesn't cross the midline
  • Can spread to other dermatomes
  • Can blister

29

What does herpes zoster of the nasociliary nerve cause?

Nasociliary is one of the 3 branches of V1

Supplies the back of the eye and tip of the nose

Inflammation of back of the eye can lead to blindness

30

What are the 2 types of superficial skin fungal infections?

1. Dermatophytes

  • e.g. Trichophyton rubrum
  • Cause 'tinea' infections
  • Grow in keatin

2. Yeasts 

  • E.g. candida
  • Grow on warm wet surfaces