Skin infections Flashcards
What toxins are produced by staphylococcus aureus
Panton velentine leuocidin (PVL) - prod much more necrosing infection
Exfoliative toxin - causes cleavage of epidermis -> blistering
TSST-1 toxin -> organ failure
Enterotoxin - problem with food consumption
What is impetigo
Caused by a staphylococcal infection of the surface of the epidermis
-> honey-coloured crust on an eroded base
It often occurs around the nose and mouth, but can occur anywhere
What is bullous impetigo
Bac making exfoliative toxin
Superficial blisters that are easily broken
What is ecthyhma
Ecthyma is full thickness involvement of the epidermis.
These lesions look like firmly adherent crust on a background of erythema. The crust will not come off – the surface of the skin is dying.
It commonly occurs after infected insect bites, or infected wounds.
What is the progression of an abscess
Starts off as infected follicle
Expands -> cavity formation (in which there is pus)
how do you treat an abscess
Incise and let pus out
Treat with antibiotics
What is staphylococcal scalded skin syndrome
systemic, widespread desquamatisation (and redness) of epidermis caused by exfoliative toxin getting into bloodstream
Occurs in kids <5
Treat with antibiotics and emollients
Whats the difference between staphylococcal scalded skin syndrome and toxic epidermal necrolysis
TEN = due to allergic to reaction to drug
TEN involves skin AND mucous memb
What is treponema pallidum
gram neg spirochete
cause of syphilis
What are the stages of syphilis
1 - Primary - painless ulcer at site of innoculation that then heals
2- Secondary - : Disseminated infection, and generalised rash and lymphadenopathy. get better
Latent phase
3- Tertiary - Skin, neurological and vascular manifestations
Features of primary phase syphilis
Chancre seen at site of inoculation
Painless ulcer
heals - maybe scr, maybe not
Features of secondary syph
flu-like illness, accompanied by rash and lymphadenopathy
Widespread rash over body
warty lesions around perineul, axilla and groin
feat or tertiary syph
Vascular abn - eg thoraci aneurism (dilation of throacic aorta)
neurosyph - dementia, depression, headaches etc
What is congenital syph
Babies born to mothers still infected syph is transplacental most die or premature born alive - will have feat similar to secondary All preg mothers now screened
types of herpes simples
HSV1 - oral
HSV2 - genital
What is the appearance of herpes blisters
Vesicles on an erythematous base are seen. These progress, to form pustules. These pustules begin to crust, and then get better.
What is the common first presentation of herpes
stromatitis - inflammation of mouth
treat with acyclovir
`What is the treatment of eczma herpeticum
intravenous antibiotics, intravenous acyclovir, emollients and topical steroids
What is the common name for VZV rash and what are some features
Chicken pox
rash preceded by headache
Virus lays dormant in neurones - when reactivateswe see shingles. This can be bullous – so we may see blistering. Patients may suffer from post-herpetic neuralgia
What is an example of dermatophytes
Trichophyton rubrum
What do dermatophytes live off and cause
Live off keratin
Cause tinea
What is tinea unguium
dermatophyte infection of nail (yellow crumbly nail)
Clippings taken to confirm
treat with 3 month course of anti-fungals
What is tinea capitus
Dermatophyte infection of the scalp
only occurs in children (adults have anti-fungal chem in sebum of hair)
treat w/ oral anti-fungals
What is another name for ringworm
Tinea manuum
Where is candida intertrigo often seen
mouth, genital area, under the breast and in the axilla
what type of scabies is not spread through human contact
crusted scabies - immunosuppressed patient has thousands of of mites on skin (normal = 15-20)
What is the presentation of scabies
For the first 4 weeks, the patient is asymptomatic. They then develop a type IV hypersensitivity reaction (allergic reaction) to the mite and its faeces. Then, they develop a very itchy, exematous rash (this keeps them awake at night). At this stage, they have BURROWS and a WIDESPREAD RASH.
What are some common sites of scabies burrows
under breasts genital area armpits back of hands strip around umbilical cubital fossa
