Skin Infections and Infestations Flashcards
What are the common viruses that infect the skin?
Human papilloma
Herpes simplex
Herpes zoster
Molluscum contagiosum
What are the common bacterium that infect the skin?
Staph aureus
Streptococcus
Corynebacterium miniutissimum
What are the common yeast/fungi that infect the skin?
Candida albicans
Pityosporum
True fungi
What is the ectoparasite that affects the skin?
Scabies
Incubation of warts
Approx. 4 months
How do you get warts?
Direct inoculation
Peak age incidence of warts (not genital)
12 - 16 years
Types of warts
Plantar Genital Plane Filiform Mosaic
What % of warts regress within 2 years?
65%
Treatment of warts
None
Chemical paints
Cryotherapy
Imiquimod (genital)
What is cryotherapy?
Liquid nitrogen
What does HSV cause?
Labial warts
Genital warts
Whitlow
Cornea
Treatment of HSV
Aciclovir
What does HZV cause?
Shingles
Treatment of HZV
Oral Aciclovir
Peak age incidence of molluscum contagiousum
10 years old
Incubation of molluscum contagiousum
2 weeks - 6 months
How long would it take for molluscum contagiousum to regress?
6 - 9 months
Treatment of molluscum contagiosum?
None
Cryotherapy
Expression + antiseptic
What can staph aureus cause?
Boils, carbuncles, styes Folliculitis Impetigo Ecthyma Eczema flare ups SSSS TSS
What can streptococci cause?
Impetigo Ecthyma Erysipelas Cellulitis Eczema flare ups Necrotising fasciitis Guttate psoriasis
What can candida cause?
Thrust - oral - vaginal Balanitis Angular stomatitis Intertrigo Nappy rash Chronic paronychia
What can true fungi cause?
Tinea pedis Tinea cruris Tinea corporis Tinea faceii/barbae Onchhomyocosis
Can you get rid of HSV once you have got it?
No
Where does HSV sit?
Dorsal route ganglia
What happens to episodes of HSV as time goes on?
Less frequent and less severe
As episodes of HSV become more frequent, what may appear before the spots?
Sensory symptoms
On fragile skin e.g. genitals, what can HSV come up as instead of pustules?
Erosions
What do you get when you acquire VZV for the first time?
Chickenpox
What results if a VZV is reactivated later on?
Shingles
Pathology of shingles
Virus comes down the peripheral nerves
Pain in HSV vs HZV
HZV much more pain
When does the pain in HZV occur compared to the rash?
Pain happens a few days before the rash
How do the vesicles appear in HZV?
Dermatomal distribution
When are your vesicles no longer infective in HZV?
When they crust over and the liquid dries up
What can HZV cross?
Placenta
If HZV gets where, this can be an emergency?
Eyes
Presentation of impetigo
Honeycomb appearance
Golden cry flakey crust
Is impetigo contagious?
Extremely
Where is it most common to get impetigo?
Head and neck
Treatment of boils
Drain pus
Antibiotics
What is ecthyma?
Localised cutaneous infection
Presentation of ecthyma
Localised
Crust in the middle
Ring of erythema
Treatment of ecthyma
Antibiotics
Where is the most common site of cellulitis?
Below the knee
What type of areas does candida albicans like?
Moist, gooey conditions
Presentation of candida albicans
Red erythema
Satellite pustules
What is paranicia?
Inflammation of nail fold
Most common cause of chronic paranicia
Candida albicans
Treatment of paranicia
Co-trimizol
What is the medical term for athlete’s foot?
Tinea pedis
What % of adult population has tinea pedis?
20%
Where is the most common place to get tinea pedis? Why?
Between 4th and 5th toes
They are squished together the most
Treatment of tinea pedis
Co-trimezol
Topinephine
What is tinea corposis also known as?
Ringworm
What is tinea cruris?
Fungal infection of the crotch
How can tinea cruris commonly be caused?
Athletes foot creeping up
What is tinea barbi?
Fungal infection of hair follicles
Lesions present in scabies
Burrow
Papules and vesicles
Excoriations
Pustules
How can you catch scabies?
Has to be from humans, not animals Close contact for at least one minute - school - family - sexual Usually on hands
Pathology of scabies
After 6 weeks, the mite burrows into the skin and produces faeces that you become allergic to
What is the main presenting symptom of scabies and when is it at its worse?
Itching
Nighttime
Presentation of scabies
Itching
Burrows
Widespread rash
Who needs to be treated for scabies?
Patient
ALL close contacts
Treatment of scabies
Licolir
How is scabies cured?
Licolir
Leave on 8 - 12 hours then wash off
Repeat 7 days later to get rid of any fresh hatched eggs missed
What would be the cause of a persistence of a rash in treated scabies?
Treatment incorrect - ALL contacts not treated simultaneously - ALL patients not treatment Diagnosis incorrect Too much treatment - can cause eczema and itching
What can be done to prevent shingles and in who?
Vaccine
- subcutaneously
- live attenuated
70 - 79 y/o
Main contraindication to shingles vaccine
Immunosuppression
Causative organisms of impetigo
Staph areus
Strep pyogenes
Who is impetigo common in?
Children
Particularly in warm weather
Incubation period of impetigo
4 - 10 days
Is impetigo contagious?
Yes, very
Treatment of impetigo if it is limited, localised disease
Topical fusidic acid 1st line
Topical retapamulin acid 2nd line
If MRSA - Topical mupirocin
Treatment of impetigo if extensive disease
Oral flucloxacillin
Oral erythromycin if penicillin allergy
Should children be excluded from school if have impetigo?
Yes
- until lesions crusted over or
- 48 hours after commencing antibiotic treatment
Causative organism of molluscum contagiosum
Molluscum contagiousum virus
Transmission of molluscum contagiosum
Close direct contact
Indirectly via fomites (contaminated surfaces) e.g. flannels and shared towels
Sexual
Features of rash of molluscum contagiosum
Pinkish or pearly white papules with a central umbilication, which are up to 5mm n diameter
Where do lesions appear in mollucsum contagiousum?
Clusters in areas on anywhere on the body
EXCEPT
- palms
- soles of feet
Is molluscum contagiousum a self limiting condition?
Yes
Should children with molluscum contagiousum be excluded from school?
No
Who should be referred with mollsucum contagiousum?
HIV positive with extensive lesions
Eyelid margin or ocular lesions and assosiated red eye
Adults with anogenital lesions
Treatment of fungal nail infection
Oral Terbinafine
What is marjolins ulcer?
SSC occurring at sites of chronic inflammation or previous injury
What is pyoderma gangrenosum associated with?
IBD
Presentation of pyoderma gangrenosum
Commonly found on lower limbs
Painful
Size of an insect bite which grows
Red base and yellow topping (margarita pizza)
Treatment of pyoderma gangrenosum
Steriods
What are stress ulcers due to burns referred as and what may they cause?
Curlings ulcer
Haematemesis
What is the parkland formula used for?
Calculate the volume of IV fluid required for resuscitation over the first 24 hours after a burn
What is seborrheic dermatitis in adults due to?
Inflammatory reaction to Malassezia furfur
