Skin Infections

Question 1

What is cellulitis?

Answer 1

Infection of the dermis

Question 2

List 5 types of cellulitis and the organisms that most commonly cause them.

Answer 2

1. Spontaneous (poor lymph drainage and venous drainage of lower leg). Caused by streptococcus pyrogenes and staphylococcus aureus.
   2.Secondary cellulitis to wounds and ulcers. Caused by staph aureus.
2. Diabetic foot. Caused by gram positive, gram negative, anaerobic, aerobic.
3. Water related infections: fresh waster: aeromonas hydrophilia. Salt water: vibrio especially vibrio vulnificus.
4. Bites and clenched fist injuries.
   Cat/dog: pasturella multicoda
   Human: mixed oral flora

Question 3

What is necrotising fasciitis and the microbes that cause it?

Answer 3

Rapid necrosis of tissue aka flesh eating infection.

Caused by streptococcus pyrogenes, staphylococcus aureus and clostridium perfringens (causes gas gangrene).

Question 4

Conditions caused by streptococcus pyrogenes?

Answer 4

• erysipelas

- impetigo

Question 5

Difference between impetigo and bulbous impetigo?

Answer 5

Impetigo is the infection of the epidermis proper. However bullous impetigo also involved blistering.

Question 6

What is mastoiditis and what causes it and when is someone most likely to get it?

Answer 6

Mastoiditis is the infection of the breast tissue.
Someone is most likely to get it when post partum.
It is caused by staphylococcus aureus most commonly but also sometimes caused by streptococcus agalactiae.

Question 7

Scalded skin syndrome?

Answer 7

Neonatal
Gets into blood
Spreads 
Can infect all skin
Staphylococcus aureus.

Question 8

Furunculosis and carbuncles?

Answer 8

Infection of a hair follicle.

Furuncle is the boil and the carbuncle is a multiloculated furuncle.

Question 9

Necrotising fasciitis?

Answer 9

Rapid progressive cellulitis with tissue necrosis and gas.
Caused by streptococcus pyogenes, staphylococcus aureus and clostridium perfringens (gas gangrene).
Water related infections
Polymicrobial in diabetics.

Question 10

Folliculitis?

Answer 10

Caused by staphylococcus aureus.

Infection of multiple hair follicles.

Question 11

Treatment and diagnosis of skin infections.

Answer 11

Ask history, where they could’ve acquired the infection.
Do physical examination looking at layers possibly involved and where infection is.
Treat depending on what it is e.g. Treat impetigo topically if not widespread.
Furunculosis drain pus
Necrotising fasciitis aggressive debridement and broad spectrum intravenous antibiotics.