Skin infections

Question 1

Describe Staphylococcus aureus

Answer 1

Gram positive

commensal (nose, skin, arms, groins)

Question 2

What virulence factors does Staph aureus produce?

Answer 2

Exfoliative toxin - blisters
Panton valentine leucidin - severe infection
Toxin shock syndrome toxin 1 - sick, fever, malaise, tachycardia, organ failure
Enterotoxin (food poisoning)

Question 3

What does the pattern of disease in Staph aureus depend on?

Answer 3

where the infection is

stratum corneum - impetigo
Epidermis - ecthyma
Hair follicle - folliculitis
Multiple abscesses - carbuncle

Question 4

What is Staphylococcal scalded skin syndrome?

Answer 4

Infection starts somewhere - release exfoliative toxin into bloodstream which causes systemic effects.

Children under the age of 5

Widespread redness

Only affects SKIN NOT MUCOUS MEMBRANES

Question 5

What is toxic epidermal necrolysis?

Answer 5

Similar to Staphylococcal scalded skin syndrome but also affects MUCOUS MEMBRANES in mouth and eyes.

Question 6

Describe trepenoma pallidum and what does it cause?

Answer 6

Spiral-shaped

causes symphilis
increases transmission of HIV

Question 7

What are the three phases of syphilis infection?

Answer 7

Primary - painless ulcer at site (genital or oral) - 3-8weeks

Secondary - widespread rash including palms and soles, lymphadenopathy - 6-17weeks

Tertiary - no treatment then skin, brain and vascular symptoms like thoracic aneurysm, dementia, depression, psychosis…

Question 8

What can syphilis cause in pregnant women?

Answer 8

miscarriage, still birth, prematurity, rashes

foetal abnormalities - rashes, neurological problems, bone disease

can be passed on

Question 9

Which human herpes viruses cause skin infections?

Answer 9

1-3

Question 10

What are the two types of herpes simplex virus and where do they infect generally?

Answer 10

Both are muco-epithelial

type 1 - oral
type 2 - genital

Question 11

Describe the presentation of herpes simplex virus?

Answer 11

vesicular rash for 2 weeks, eczema herpeticum, herpes encephalitis

the rash comes back in times of stress or infection

Question 12

What is the treatment of HSV?

Answer 12

Anti viral drugs

Acyclovir

Question 13

What virus causes chickenpox and shingles?

Answer 13

Varicella Zoster Virus

via inhalation or contact

Question 14

What are the symptoms of VZV infection?

Answer 14

sore throat
fever
malaise
vesicular rash mostly on face and less on body 
mouth involved by not hands and feet 

Heal in 2 weeks

Question 15

What is the problem with the first three human herpes viruses (HSV1/2 and VZV)?

Answer 15

Latency - live on in neurons

reactivate

Question 16

What is shingles caused by and what is the treatment?

Answer 16

Latent VZV
affects dorsal root ganglion
rash is along dermatomes

Preventable by vaccine
given to over 70s - prevent blindness

Treatment - acyclovir