Cutaneous infections Flashcards
SCABIES
i) what is it caused by? how long can it take for a rash to appear after initial infestation?
ii) what is the common presentation? where is the classic location of the rash?
iii) what is first line treatment? where should it be applied? how long for?
iv) what can be given if the scabies are difficult to treat? how long may itching continue after sucessful treatment?
v) what are crusted scabies? wo do they occur in? how do they appear? name two treatments
i) caused by mites (sarcoptes scabeiei) and can take 8 weeks for rash to appear
ii) itchy small red spots with track marks where mites have burrowed - see in finger webs (can spread to whole body)
iii) permethrin cream - apply to whole body and leave on for 8-12 hours then wash off (repeat a week later)
iv) hard to treat > give oral ivermectin and repeat 1 week later
can take 4 weeks for itching to resolve
v) crusted scabies is serious and occurs in immunocompromised
extremely contagoous and red skin > scaly plaques (can be miss dx as psoriasis) - may not have itch as dont mount an immune response
tx with ivermectin and isolation
HEADLICE
i) which parasite causes it? how do they spread? (2)
ii) which treatment can be given? how long is it left on for? when is it repeated?
i) pediculus humanus > spread via close contact or sharing equipment eg towels
ii) dimeticone 4% lotion > leave on for 8 hours and repeat after 7 days
TINEA
i) what type of infection is it? what is it aka? why?
ii) what are the three most common types affecting scalp, trunk/legs/arms, feet
ii) what does tinea of the scalp cause? who does it mostly affect? what is a kerion? what is the most useful diagnostic investigation?
iii) what is the tx of scalp disease? of body disease?
iv) what is tinea pedis aka?
i) fungal dermatophyte infection aka ring worm due to px with annular/ring shaped lesions
ii) scalp - tinea capitis, body - corporis, feet - pedis
ii) scalp = scarring alopecia especially in children
kerion- raised pustular boggy rash (happens if untreated)
most useful investigation is a scalp scraping
iii) scalp - oral antifungals and ketoconazole shampoo for two weeks to reduce transmission
body - oral fluconazole
iv) atheletes foot
FUNGAL NAIL INFECTION
i) what is it called? name three things that can cause it? name two risk factors
ii) name three features? name two DDs
iii) name two investigations
iv) when may they not be treated? what should be done before starting treatment?
v) what should be given for each type of infection? (2)
i) onychomycosis caused by dermatophytes (trichophyton rubrun), yeast (candida), non dermatophyte moulds
RFs = increasing age and DM
ii) unsightly, thick, rough, opaque nails
DDs = psoriasis, repeated trauma, lichen planus, yellow nail syndrome
iii) nail clippings and scraping from nail
iv) no tx if asymp
get micro to confirm diagnosis before starting treatment
v) dermatophyte infection > oral terbinafine
candida infection > topical antifungal or oral if more severe
HERPES SIMPLEX VIRUS
i) name three common presenting features
ii) what is the management for each feature
iii) what is advised if a herpes attack occurs after 28 weeks gestation?
iv) which cells are seen on pap smear
i) gingivostomatitis - sores in mouth and gums
cold sores
genital ulceration
ii) tx cold sores and genital ulceration with topical aciclovir
gingo - oral aciclovir and chlorhexidine mouth wash
iii) elective caesarian
iv) multinucleated giant cells
HERPES ZOSTER (SHINGLES)
i) name three way it is characterised? what is it due to reactivation of? what happens
ii) name three risk factors? what are the most commonly affected dermatomes? name three features of the prodromal period
iii) name three features of the rash that is seen initially? what does it change to? how is a dx usually made?
iv) what is given first line? what should be given in the first 72 hours?
v) what is the most common complication?
i) acute unilateral painful blistering rash due to reactivation of VZV - lies dormant in dorsal root or cranial root ganglia following primary infection
ii) RFs = increasing age, HIV, other immunosuppresion eg chemo
dermatomes = T1-L2
prodromal - burning pain over affected dermatome for 2-3 days, fever, headache, lethargy
iii) rash - initially erythematous and macular (flat red) then changes to vesicular
well demarcated to dermatome and doesnt cross the midline
dx is usually clinical
iv) first line are NSAIDs and paracetamol
may consider amitryptiline or corticosteroids
give antivirals within 72hrs for most patients (aciclovir)
v) post herpetic neuralgia
