Skin infections Flashcards
skin - function
provides anatomical barrier
main method of heat regulation
sensory input from the body
storage for lipids and water
drug absorption and waste excretion
oily skin - features
- more secretion from sebaceous glands
- more bacterial colonisation
- skin becomes heavier and thicker
- more risk of pore blockage
- more spots and pimples
comedones (blackheads) features
- feature of acne vulgaris
- build up of keratin and sebum
- block pores and oxidise giving ‘black’ appearance
bacterial skin infections
furuncles and carbuncles
acne
erysipelas
impetigo
furuncles
infection of skin - pockets filled with pus
organism responsible - staph. aureus
red, painful and swollen
drain pus - antibiotics not always necessary
acne
term for lessons arising from
- comedones
- upules
- pustules
- nodules
- inflammatory cysts
acne prevalence
age 13-18
- 80% teenagers affected
age 25-40
- 5% women, 1% men
- late onset acne also possible
acne - causes
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
acne - complications
made worse by
- some contraceptive pills (progestogen)
- greasy skin cleaners
- systemic steroid treatment
- some anticonvulsant drugs
acne - local management
reduce excess skin oil
- cleansers - gentle soap
antibacterial agents
- benzoyl peroxide
- retinoids
- antibiotic lotions
acne - systemic management
if local treatments fail:
antibiotics
- tetracycline based
retinoids
- isotretinoin
hormone manipulation
- anti-androgens
erysipelas - faetures
- bacteria - streptococcus pyogenes
- defined sharp raised border
- may blister and peel
- usually systemic symptoms - fever, rigors
erysipelas management
systemic antibiotics
erysipelas - complications
can progress to
- necrotising fasciitis
- septic shock
impetigo features
highly infections skin disease
- staphylococcal or streptococcal
- crusty red blister appearance
- often associated with eczema
- treated with topicals antibiotics - sometimes systemic
common viral skin infections
herpes simplex
shingles
molluscs contagiosum
warts
herpes simplex infections - features
affect single dermatome or adjacent dermatomes
activated by ‘trauma’
- physical, chemical, UV light
lives in nerves
treated with aciclovir
herpes zoster
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
molloscum contagiousum features
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
Warts
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
fungal skin infections - dermatophytes
athletes foot
nail infections (onycholysis)
ringworm
intertrigo
pityriasis versicolor
athletes foot features
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
onycholysis
nail bed fungal infection
usually tine ungium infection
nail becomes malformed, thick and crumbly
may be seen with athletes foot
ringworm
can affect different parts of the body
groin - tine curis
body - tine corporis
scalp - tine wapitis
intertrigo
fungal infection due to chain in moist body folds
treat with typical anti fungal cream
pityriasis versicolor
causes by ptyrosporum orbicular
- usually a harmless commensal
skin infestations
scabies
lice
scabies - features
infection with the scabies mite
from skin to skin contact with an infected individual
- occasionally from bedding
usually 10-12 mites infect the host
scabies - symptoms
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
scabies - treatment
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
lice features
3 types
- head
- pubic
- body
transmitted by close contact with an infected individual
transmitted by shared items
- clothing combs, bedding, brushes and toilet seats
lice treatment
body lice - treated by personal and clothing hygiene
chemical insecticides
- permethrin
- malathion
- phonothrin
