Infections of the Skin

Question 1

What is the epidermis?

Answer 1

Hard horny layer of dead cells.

Question 2

What antimicrobial substances does the skin produce?

Answer 2

Fatty acids, sebum and defensins.

Question 3

What defensive properties does the skin have?

Answer 3

Surface is dry, constant sloughing, acidic pH, sweat secretion and rich blood supply.

Question 4

What are the normal skin microbiota?

Answer 4

Streptococcus pyogenes

propionibacterium acnes

corynebacterium sp

candida sp.

Question 5

What are the two types of coagulase-negative Staphylococci?

Answer 5

Staphylococcus epidermis and Staphylococcus aureus.

Question 6

What is the site of ringworm?

Answer 6

Keratinised epithelium.

Question 7

What is an example of a skin infection in the epidermis?

Answer 7

Impetigo.

Question 8

What is the site of folliculitis?

Answer 8

The hair follicles.

Question 9

What is an example of a skin infection in the subcutaneous fat?

Answer 9

Cellulitis.

Question 10

What are the routes of infection through the skin?

Answer 10

Through pores and hair follicles.

Question 11

What are the routes of infections through wounds?

Answer 11

Scratches, cuts and burns.

Question 12

What could cause infection through bites?

Answer 12

Insects and animals.

Question 13

What are some bacterial infections of the skin?

Answer 13

Staphylococcus aureus

Streptococcus pyogenes

Pseudomonas aeruginosa

Mycobacterium tuberculosis.

Question 14

What is the morphology of Streptococcus pyogenes and Staphylococcus aureus?

Answer 14

Cocci morphology.

Question 15

How does strep pyogenes grow?

Answer 15

It grows in chains.

Question 16

How does staph aureus grow?

Answer 16

In clusters

Question 17

What gram is strep pyogenes and staph aureus?

Answer 17

Positive

Question 18

How is strep pyogenes classified?

Answer 18

As a group A streptococcus.

Question 19

What are the antibiotic resistant strains of staph aureus?

Answer 19

MRSA and VRSA.

Question 20

What does MRSA and VRSA stand for?

Answer 20

Meticillin-resistant Staphylococcus aureus and Vancomycin-resistant Staphylococcus aureus.

Question 21

What is the morphology of Pseudomonas aeruginosa?

Answer 21

Coccobacillus morphology.

Question 22

What gram is pseudomonas aeruginosa?

Answer 22

Gram negative.

Question 23

What does it mean to have monotrichous flagella?

Answer 23

Having a single flagellum at one pole.

Question 24

Give an example of a bacteria that has monotrichous flagellum.

Answer 24

Pseudomonas aeruginosa.

Question 25

What toxin does Pseudomonas aeruginosa produce?

Answer 25

Exotoxin A.

Question 26

Where do pseudomonas aeruginosa colonise?

Answer 26

Catheters etc.

Question 27

What are the different forms of skin lesions?

Answer 27

Macule, papule, vesicle and ulcer.

Question 28

What does a macule look like?

Answer 28

Flat, red, local inflammation.

Question 29

What does a papule look like?

Answer 29

Raised, red, more marked inflammation.

Question 30

What does a vesicle look like?

Answer 30

A small blister.

Question 31

What does an ulcer look like?

Answer 31

Disruption of epithelium.

Question 32

What is an abscess?

Answer 32

Collection of pus; pustule.

Question 33

What is pyoderma?

Answer 33

Pus-forming skin infection; cutaneous abscess.

Question 34

What is impetigo?

Answer 34

Vesicles developing into rupturing pustules then forming dried crusts.

Question 35

What is ecthyma?

Answer 35

Rupturing vesicles leading to erythematous lesions and dried crusts.

Question 36

What is folliculitis?

Answer 36

Inflammation at a hair follicle.

Question 37

What is a furuncle?

Answer 37

Boil; deep folliculitis.

Question 38

What is a carbuncle?

Answer 38

A collection of boils.

Question 39

What is erysipelas?

Answer 39

Erythema and inflammation of superficial dermis.

Question 40

What is cellulitis?

Answer 40

Erythematous inflammation affecting deeper dermis and subcutaneous fat.

Question 41

What is acne?

Answer 41

Infection of sebaceous follicles.

Question 42

What is necrotising fasciitis?

Answer 42

Cellulitis with necrosis affecting skin, deeper fascia and sometimes muscle.

Question 43

What are the bacteria usually responsible for cellulitis?

Answer 43

Staphylococcus and Streptococcus.

Question 44

What is dehiscence?

Answer 44

Wound rupture along surgical suture.

Question 45

What are two types of fungal infections of the skin?

Answer 45

Dermatophytes and yeasts.

Question 46

What are examples of dermatophytes?

Answer 46

Tinea pedis, Tinea corporis and Tinea cruris.

Question 47

What are example of yeast infections?

Answer 47

Candida albicans and Malassezia furfur.

Question 48

What viral infection presents as warts/genital warts?

Answer 48

Human papilloma viruses (HPV).

Question 49

What viral infection presents as cold sores?

Answer 49

Herpes simplex virus 1 (HSV1).

Question 50

What are the observable symptoms of herpes simplex virus 2 (HSV2)?

Answer 50

Genital herpes.

Question 51

What are the symptoms of varicella zoster virus (VZW)?

Answer 51

Chicken pox and shingles.

Question 52

What are the symptoms of coxsackie A virus?

Answer 52

Hand, foot and mouth disease.

Question 53

What is an example of a parasite of the skin?

Answer 53

Sarcoptes scabiei (mite).

Question 54

What does sarcoptes scabiei cause?

Answer 54

Scabies.

Question 55

How does sarcoptes scabiei cause scabies?

Answer 55

Mite burrows into skin and the female lays eggs.

Question 56

What can infection by sarcoptes scabiei lead to?

Answer 56

Hypersensitivity and superinfection.

Question 57

What does it mean that the scabies infection is asymptomatic?

Answer 57

That the patient can be infected with the disease and not show any symptoms.

Question 58

What is lancefield grouping?

Answer 58

Grouping catalase-negative and coagulase-negative bacteria based on the carbohydrate composition of bacterial antigens found on their cell walls.

Question 59

What forms pus?

Answer 59

Dead white blood cells and bacteria with tissue debris and serum.