Skin Infections Flashcards
What virus cause skin infections
HPV
Herpes simplex ( HSV)
Herpes Zoster (HZV)
Molluscum contagiosum
What bacteria cause skin infection
Normal skin flora protect but if skin damage micro-organism can penetrate
S.aureus
Strep
Corynebacterium minitissimum in acne
What fungi cause skin infection
Tinea Candida albican Yeast Piturosporium True fungi
What ectoparasites cause skin infection
Scabies
Cutaneous leishmaniasis
What does HPV lead too
Warts on body Hyperkeratotoic papules or nodules Most common at sites of trauma Incubation = 4 months Transferred by direct skin contact
How do you Rx
Consider if painful, unsightly or persist
Should resolve 24 months
Chemical paint
Cryotherapy
Imiquidmod for genital - usually sexual transmission
What does primary exposure to HSV cause
1st clinical episode
Most severe
Virus becomes latent in neural tissue in DRG
What can reactivate virus
Trauma Menstruation Sunlight Fever Virus then tracts down nerves
How does HSV present
Closely tinny packed vesicle / pustule Monomorphic - same May only see erosions if skin is fragile e.g. genitals May see ulcers on thick skin Often proceeded by burning or itching
If recurrent vesicles what should you suspect
HSV
Who is at risk of severe infection
Immunosuppressed
Atopic tendency
How do you Rx
Acyclovir - oral or topical
What does primary exposure to HZV lead too
Chicken pox
Then becomes latent
When reactivated = shingles
What are features of shingles
Pain in dermatome region as virus tracks down nerves
Rash after 4 days of pain
Dermatomal
Vesicular
If in ophthalmic devision of 5th CN = urgent referral
What are complications
Scarring
Post-shingles neuralgia
Meningnitis
Encephalitis
How do you Rx
Opthamologist if in eye area
Oral acyclovir if immunocompromised, >50, eye involvement
IV if severe
When are you non-infective
When vesicles dry up
Who gets shingles vaccine and what type
All elderly 70-79 SC
Live attenuated so CI if immunosuppressed
What is molluscs contagiosum
Common skin infection caused by MCV virus
Transmission via close contact
Very common in children, immunocompromised, atop eczema
What are the features
Pinky pearly white papules Central umbilication Up to 5mm in diameter Appear in clusters Common on trunk and flexure May get lesions on genitalia if sex
How do you Rx
Self limiting within 18 months Do not share towels as contagious Cryotherapy if lesion troublesome GUM if on genitals + STI screen Ophthalmology if eye lid HIV if +Ve
What are complications and how do you treat
Eczema or inflammation so Rx
Emollient or steroid if itch
Ax if bacterial infection on top - topical fusidic or fluclox
What is pityriasis Rosea
Acute self-limiting rash
Herald patch - usually on trunk to start
Followed by erythematous oval scaly patches
CHaracterisitc distribution
Longitudinal line
What causes and how do you treat
Viral-predrome
Lasts 6-12 weeks - self limiting
Symptomatic treatment of itch wit antihistamine, emollients, steroid
What is impetigo and what causes
Superficial bacterial skin infection that occurs when bacteria enter through a break in the skin
S.aureus = 70%
Strep A
Can be primary or secondary to eczema / scabies / bite
How does it present
Golden crusted lesion
Tend to be on face and flexures
How do you Rx
Topical fusidic acid = 1st line if local
Fusabet = Ax + steroid
Flucloxacillin if extensive
Oral erythromycin if allergic
Do you exclude from school
Yes till lesions crust or 48 hours on Ax
What is erysipelas and what causes / RF
Form of cellulitis but only in dermis and upper SC tissue
Strep pyogene
S.aureus
RF Wounds Local ulcer Immunosuppression Minor skin injury
What are the features
Most common in LL Swelling Erythema Warm Painful May have associated lymphangitis Systemically unwell - fever / rigors Raised plateau into erythema
Differentiated from cellulitis as well defined red raised border
How do you Rx
IV Ax - fluclox or benpen
Rest
Leg elevation
Analgesia
What is a furuncle
Abcess in hair follicle
Known as boil
What do you do if recurrent
Dip urine to check for glucose
How do you Rx
Drain pus then Ax
What is carbuncles
Lots of furuncles together
What is ecthyma
Minature cellulitis
Much more localised
Crust + rim of erythema
How do you Rx
Oral Ax to cover staph and strep
What is cellulitis and features of cellulitis and what can it lead too
Bacterial infection involving deep subcutaneous tissue
Diffuse swollen
Red
Tender
Hot
Fever and rigors
Can lead to necrosis, abscess + septicaemia
Infection enters through trauma e.g. ulcer or athletes foot
What does corynebacterium minutissiumum cause
Erythrasma
Pitted keratosis
What is erythrasma
Asymptomatic flat, scaly pink or brown rash
Affects groin or axillae
Similar to athletes groin
How do you Rx
Topical anti-fungal
Ax - erythromycin topical or oral if extensive
What types of superficial fungal infection
Dermatophyte - tine / ringworm
Yeast - candida/ Malazzeia
Moulds - aspergillus
What does candida yeast cause
Thrush Balantitis Angular stomatisis Nappy rash Chronic paronyhia - inflammation of nail fold
How do you Rx
Canistan
What is a typical candida infection
Affects moist areas such as breast / mucosal
Brick red erythema with satellite pustules in flexures
White plaque on mucosal
What is tinea
Dermatophyte fungal infection
What is tinea pedis
Athletes foot White macerated rash Scaling Flaking Itching Fissuring
What is tinea corporis
Ring worm Well defined annular, erythematous lesions Scaly Itchy Papules and pustules Flakey skin around
How do you Dx
Skin scrapings sent for microscopy and culture
What is tinea cruris
Infection round the crotch
What makes fungal infections worse
Steroid
Can cause tinea incognito (ill defined and less scaly)
How do you Rx
Correct predisposing where possible - Moist area - Immunosuppression Topical anti-fungal - terbinafine Anti-Fungal shampoo Oral anti-fungal if doesn't improve / severe / widespread or nail infection - itranazole
What is tinea capitis and what is tinea manuum
Capitas
Fungal infection in the scalp
Itchy, dry erythematous scalp
Patches of broken hair
Manuum
Scaling and dryness / white of palmar creases of hand
What can it lead too
Scarring alopecia
How do you Rx
Oral anti-fungal + topical anti-fungal shampoo
When do you think fungal
If not gone away with Ax
What are typical fungal skin infections
Circular patch
Flaky skin around erythematous ring
Steroids worsen
What causes fungal nail infection (onychomycosis)
Dermatophytes - tinea
Candida yeast
Non-dermatophye mould (aspergillus)
What are RF
Age
DM
What are features
Thick, rough, opaque nal
Tinea unguium
- Yellow discoluration
- Thickened nail
What is DDX
Psoriasis
Trauma
Lichen planus
Yellow nail
How do you Dx superficial fungal infection
Nail clipping or scrapping before Rx
Skin swab for yeasts
If caused by dermatophyte
Oral terbinafine for 6 weeks to 6 months
Requires LFT monitoring
If caused by candida
Itracanazole
Topical if mild but require longer course
What is pityriasis versicolour
Superficial cutaneous fungal infection with Malazzeia
Common on trunk
How does it present
Look at photo Hypopigmented / pink or brownn patches Scales = common Mild itch Fail to tan on sun exposure
What is predisposing
Immunosuppression
Malnutrition
Cushings
How do you Rx
Topical anti-fungal
Send sample if fail to respond
What causes Scabies
Sarcoptes scabiei
Mite infestation
How do you get scabies
Close contact with human for about a minute
What does it do
Mite burrows into skin
Leaves egg in striatum corneum
Tend to be in cool peripheral places
Protein in poo = allergic reaction
What happens
DADS RASH
Papules+ vesicles develop after 6 weeks
Excoriations
Widespread pruritus - type 4
What can stay after treatment
Itch
How do you Dx
Presence of burrow
Dermatoscope to view mites
Skin scrap
How do you Rx
Cream all over body for 8-12 hours - scabicide
Repeat after 7 days
Treat all house hold contacts
Anti-Histamine for itch
What is a viral exanthema
Itchy rash associated with any viral illness
Fever, malaise, headache then rash
What causes
Chicken pox Measles <1 without MMR Rubella Scarlet fever Parovirus B-19 Roseala infantum
What do you do for oral thrush
Swab to confirm
Possibly test for HIV
Sporonox spray or nystatin
Fluclonazole tablet
If skin looks infected / inflamed
Topical fusidic acid (fusabet = Ax + steroid)
Oral fluclox next
