Microbio skin infections

Question 1

Describe epidemiology of skin infections

Answer 1

25% of skin-related GP conslultations (skin problems account for 25% GP visits also)
Infection more common in hot, humid, poor environements
Autoimmune common everywhere

Question 2

Examples of common skin problems

Answer 2

Inflammatory dermatoses eg psoriasis, acne etc
fungal infection
viral infections
bacterial infections
parasitic skin infection
skin malignancy

Question 3

Example of bacterial skin infection

Answer 3

Staphylococcus aureus

Treponema pallidum

Question 4

Example of fungal skin infection

Answer 4

Trichophyton rubrum

Question 5

Examples of viral skin infection

Answer 5

herpes simplex virus
varicella zoster virus
(human papillomavirus)

Question 6

Example of parasitic skin infection

Answer 6

sarcoptes scabiei (ectoparasite)

Question 7

Example of a non-skin related fungal infection

+ where infects

Answer 7

Aspergillus

lungs and liver

Question 8

Manifestations of Staph. aureus skin infection based of location

Answer 8

Impetigo = subcorneal
Boil = hair follicle
Carbuncle = multiple adjacent hair follicles
Folliculitis = mouth of hair follicle
Ecthyma = whole epidermal layer

Question 9

Features of S. aureus skin infection

Answer 9

Usually crusty, golden (aureus) impetigo around mouth but can affect head, neck and ears
(may cause serious staphylococcal scalded skin syndrome in newborns)

Question 10

Staphylococcus aureus organism classification

Answer 10

Gram +ve

staphylococcus (spherical chains) bacteria

Question 11

Treponema pallidum classfication

Answer 11

gram -ve

spirochaetae bacterium

Question 12

Disease caused by Treponema pallidum

Answer 12

SYPHILIS!!!!!

Question 13

Transmission of Treponema pallidum

Answer 13

sexual transmission

vertical transmission -> congenital syphilis

Question 14

Disease course of syphilis

Answer 14

1’ = chancre = painful ulcer at inoculation site (weeks)
2’ = generalised rash + lymphadenopathy (months)
latent phase
3’ = skin, vasculature and BRAIN manifestations (years)

Question 15

Symptoms of 2’ syphilis

Answer 15

maculopapular rash
palmar and plantar involvement
condyloma lata at anus

Question 16

Symptoms of 3’ syphilis

Answer 16

Bone lesions -> severe facial and cranial deformity
Gummatous skin lesions
thoracic aortic aneurysm
neurosyphilis

Question 17

Symptoms of congenital syphilis

Answer 17

miscarraige/stillbirth
prematurity
rashes
bone disease
brain and neuro problems

Question 18

Herpes simplex classification and types and what they cause

Answer 18

dsDNA virus with tegument shell
Type 1 -> oral herpes
Type 2 -> genital herpes

Question 19

Symptoms of herpes

Answer 19

vesicular rash around mouth or genitals

May cause eczema herpeticum in eczema patients

Question 20

Why is herpes infection recurrent?

And typical symptom

Answer 20

Virus has latency in neurones

Can migrate to cell body and cause unilateral dermatomal infection

Question 21

Varicella zoster virus classification and types and what they cause

Answer 21

(also called herpes zoster virus)
dsDNA virus with tegument shell
Part of human herpes virus family
Type 8
Causes CHICKENPOX (preferentially called varicella) and then recurrent infection = SHINGLES (preferentially called herpes zoster)

Question 22

Symptoms of herpes zoster = SHINGLES

Answer 22

Unilateral dermatomally distributed vesicular/bullous rash

Question 23

Trichophyton rubrum classification

Answer 23

superficial fungal skin infection with long hyphae

grows in keratin

Question 24

Types of Trichophyton rubrum based on location

Answer 24

Tinea unguium = toenail
Tinea capitis = head/scalp
Tinea facei = face
Tinea manuum = hand
Tinea pedis = foot
Tinea cruris = groin

Question 25

Sarcoptes scabei manifestation and location

Answer 25

Burrows in epidermis and lays eggs
Can see eggs and squiggly burrow in skin
Skin creases = pits, tits, ass, elbows, genitals, webs of fingers