Skin infections

Question 1

skin - function

Answer 1

provides anatomical barrier
main method of heat regulation
sensory input from the body
storage for lipids and water
drug absorption and waste excretion

Question 2

oily skin - features

Answer 2

• more secretion from sebaceous glands
• more bacterial colonisation
• skin becomes heavier and thicker
• more risk of pore blockage
• more spots and pimples

Question 3

comedones (blackheads) features

Answer 3

• feature of acne vulgaris
• build up of keratin and sebum
• block pores and oxidise giving ‘black’ appearance

Question 4

bacterial skin infections

Answer 4

furuncles and carbuncles
acne
erysipelas
impetigo

Question 5

furuncles

Answer 5

infection of skin - pockets filled with pus
organism responsible - staph. aureus
red, painful and swollen
drain pus - antibiotics not always necessary

Question 6

acne

Answer 6

term for lessons arising from
- comedones
- upules
- pustules
- nodules
- inflammatory cysts

Question 7

acne prevalence

Answer 7

age 13-18
- 80% teenagers affected
age 25-40
- 5% women, 1% men
- late onset acne also possible

Question 8

acne - causes

Answer 8

follicular sensitivity to testosterone
- increase around puberty
- build up of comedones
propionibacterium acne overgrows and leads to infection and cysts
- scars can form if cysts rupture

Question 9

acne - complications

Answer 9

made worse by
- some contraceptive pills (progestogen)
- greasy skin cleaners
- systemic steroid treatment
- some anticonvulsant drugs

Question 10

acne - local management

Answer 10

reduce excess skin oil
- cleansers - gentle soap
antibacterial agents
- benzoyl peroxide
- retinoids
- antibiotic lotions

Question 11

acne - systemic management

Answer 11

if local treatments fail:
antibiotics
- tetracycline based
retinoids
- isotretinoin
hormone manipulation
- anti-androgens

Question 12

erysipelas - faetures

Answer 12

• bacteria - streptococcus pyogenes
• defined sharp raised border
• may blister and peel
• usually systemic symptoms - fever, rigors

Question 13

erysipelas management

Answer 13

systemic antibiotics

Question 14

erysipelas - complications

Answer 14

can progress to
- necrotising fasciitis
- septic shock

Question 15

impetigo features

Answer 15

highly infections skin disease
- staphylococcal or streptococcal
- crusty red blister appearance
- often associated with eczema
- treated with topicals antibiotics - sometimes systemic

Question 16

common viral skin infections

Answer 16

herpes simplex
shingles
molluscs contagiosum
warts

Question 17

herpes simplex infections - features

Answer 17

affect single dermatome or adjacent dermatomes
activated by ‘trauma’
- physical, chemical, UV light
lives in nerves
treated with aciclovir

Question 18

herpes zoster

Answer 18

recurrent HZV
affects single dermatome
causes significant pain
- neural inflammation from virus in the nerve
pain may persist after rash has gone
- post herpetic neuralgia
treat with HIGH DOSE aciclovir

Question 19

molloscum contagiousum features

Answer 19

caused by MCV - a pox virus
resolve spontaneously in 1-2 years
usually infants and small children
clusters of small papules
- warm, moist areas
- 1-6mm size

Question 20

Warts

Answer 20

Human papilloma virus
- types 1-3 cause most wars
- types 16 and 18 cause cervical cancer

contact spread
treated by
- keratolysis
- cryosurgery
- excision
if immune competent then most resolve spontaneously

Question 21

fungal skin infections - dermatophytes

Answer 21

athletes foot
nail infections (onycholysis)
ringworm
intertrigo
pityriasis versicolor

Question 22

athletes foot features

Answer 22

typically affect feet between toes
- groin involvement also common
- usually mixed fungal and bacterial infection
- scaling and sogginess of the skin
- prevent by keeping skin clean dry and damage free
- treat with anti fungal/antibacterial cream e.g. miconazole

Question 23

onycholysis

Answer 23

nail bed fungal infection
usually tine ungium infection
nail becomes malformed, thick and crumbly
may be seen with athletes foot

Question 24

ringworm

Answer 24

can affect different parts of the body
groin - tine curis
body - tine corporis
scalp - tine wapitis

Question 25

intertrigo

Answer 25

fungal infection due to chain in moist body folds
treat with typical anti fungal cream

Question 26

pityriasis versicolor

Answer 26

causes by ptyrosporum orbicular
- usually a harmless commensal

Question 27

skin infestations

Answer 27

scabies
lice

Question 28

scabies - features

Answer 28

infection with the scabies mite
from skin to skin contact with an infected individual
- occasionally from bedding
usually 10-12 mites infect the host

Question 29

scabies - symptoms

Answer 29

burrows appear on the skin
- folds between fingers and on wrists
itch is often most troublesome feature
- more severe at night
- on trunk and limbs
rash appear on trunks and limbs
- tiny red intensely itchy bumps
rash and itch are allergy and can persist long after the infestation is gone

Question 30

scabies - treatment

Answer 30

chemical insecticides
- benzyl benzoate
- permethrin
- malathion
apply to the whole body from the chin down including under the nails
treat all close contacts whether obviously infected or not

Question 31

lice features

Answer 31

3 types
- head
- pubic
- body
transmitted by close contact with an infected individual
transmitted by shared items
- clothing combs, bedding, brushes and toilet seats

Question 32

lice treatment

Answer 32

body lice - treated by personal and clothing hygiene
chemical insecticides
- permethrin
- malathion
- phonothrin