Skin infections

Question 1

In which climates are skin conditions most prevalent?

Answer 1

Hot + humid

Question 2

What sort of infection is caused by tricophytum rubrum? Where do they grow?

Answer 2

Tinea

Grow in keratin (skin, nails + hair)

Question 3

What sort of pathogen is trycophytum rubrum?

Answer 3

Fungus

Question 4

Give 3 examples of tinea infections

Answer 4

Tinea capitis
Tinea pedis
Tinea manu

Question 5

Which pathogen is responsible for causing scabies?

Answer 5

Sarcoptes scabei

Question 6

Recall the pathophysiology of a scabies infection

Answer 6

Sarcoptes scabei burrows into the stratum corneum to cause a Type IV DHT reaction

Question 7

Give 3 common sites for scabies burrows

Answer 7

Groin
Axilla
Anticubital fossae

Question 8

Recall the main symptom of a scabies infection and how long the latent period is before symptoms are seen

Answer 8

Widespread erythrematous rash

4 week latent period

Question 9

What classification of bacterium is S aureus?

Answer 9

Gram positive

Question 10

Recall the 4 toxins produced by S aureus

Answer 10

PVL (Causes necrotising abscess)
Exfoliative toxin (causes blisters)
TSS1
Enterotoxin

Question 11

Recall 3 consequences of S aureus infection

Answer 11

Skin infection
Severe pneumonia
Sepsis

Question 12

What is impetigo? Recall the appearance of imeptigo

Answer 12

An S aureus infection of the subcorneal layer of the epidermis
Yellowish with golden crust

Question 13

What are 5 possible manifestations of S. Aureus Skin Infections? Describe what is infected in each

Answer 13

Impetigo (sub corneal layer of epidermis)
Folliculitis (mouth of hair follicle)
Ecthyma (full thickness of epidermis)
Boil (abscess of hair follicle)
Carbuncle (abscess of several adjacent hair follicles)

Question 14

What does ecythema look like?

Answer 14

Crusted thick lesion

Necrotic at surface

Question 15

Which group of the population are susceptible to Staphlococcal Scalded skin Syndrome?

Answer 15

Children < 5 years old

Exfoliative toxin causes outer layers of skin to blister + peel

Question 16

What does exfoliative toxin production by S aureus result in?

Answer 16

Bullous impetigo

Splitting of skin at higher levels of the epidermis

Question 17

What sort of pathogen is treponema pallidum? What does infection by this cause? What is the main way in which this is transmitted?

Answer 17

Gram negative bacterium
Syphilis
STD

Question 18

Recall the duration of each of the phases of syphillis infection

Answer 18

Primary = 3-8 weeks
Secondary = 6-12 weeks
Tertiary = years later

Question 19

Recall the main symptoms of the primary phase of syphillis

Answer 19

Painless ulcer at inoculation site

Question 20

Recall the symptoms of secondary syphillis

Answer 20

Disseminated infection

Generalised rash, lymphadenopathy + flu-like illness

Question 21

Describe the rash of secondary syphilis. Which areas are commonly effected?

Answer 21

Maculopapular
Erythrematous
Palms + soles

Question 22

Which body systems are affected by tertiary syphillis?

Answer 22

Skin, neurological + vascular

Question 23

What is the first-line treatment for congenital syphillis?

Answer 23

Penicillin

Question 24

Recall which serotypes of HHV are known as EBV, VZV and CMV

Answer 24

VZV = HHV3
EBV = HHV4
CMV = HHV5

Question 25

Recall which types of HSV cause oral and genital herpes

Answer 25

Oral = type 1
Genital = type 2

Question 26

Which cells are infected in an HSV infection? What is the consequence of this?

Answer 26

Neurons

HSV 1 + 2 + VZV have latency, can be reactivated in times of stress

Question 27

Which pathogen commonly infects at defective skin barriers due to eczema?

Answer 27

Herpes simplex virus

Leads to eczema herpeticum

Question 28

What disease is produced by herpes spreading to the brain?

Answer 28

Herpes encephalitis

Question 29

Which serotype of HHV is associated with Kaposi’s sarcoma?

Answer 29

HHV8

Question 30

Where does VZV have latency?

Answer 30

Dorsal root ganglia

Question 31

What are the possible severe consequences of reactivation of VZV (Herpes Zoster)?

Answer 31

When CNV is infected you get face involvement so acyclovir is given IV rather than orally so as to avoid blindess

Question 32

What is the clinical presentation of herpes simplex virus? How long does this presentation usually last?

Answer 32

Vesicular rash

2 weeks

Question 33

Describe the presentation of varicella zoster virus

Answer 33

“chickenpox”- vesicular rash
Maiaise
Fever
Sore throat

Question 34

Risks of what are increased by developing chickenpox as an adult?

Answer 34

Encephalitis

Pneumonia

Question 35

Where do candida yeasts grow?

Answer 35

Warm wet surfaces e.g. body folds