derm 2 Flashcards
herpes (shingles)
herpes zoster infection- reactivation of varicellar zoster.
presents with dermatomal pain, eruption of grouped vesicles.
pain preceeds rash, lasts 4-5 weeks.
RF: over 50, female, HIV, chronic sted use, chaemo/ malignency.
Ix: usually a clinical diagnosis
can swab + PCR.
Rx: usually self limiting but consider antiviral in all pts
famciclovir 500mg 8hrly 7/7
OR
valaciclovir 1000mg 8hrly 7/7
2nd- aciclovir 800mg 5DS 7/7
Refer if eye involvement (opthalmologist) - quicker start of antivirals.
headlice (pediculosis capitis)
an obligate ectoparasite that lives on human beings and feeds on human blood
RF: socially active- young children (3-12)
female, close living conditions.
eggs can be visible on hair 1cm from scalp.
Ix/Dx: doscivery of live young or adult louse. usually vis if 6mm from scalp.
on magnification they have dark eyespots.
may see excessive itching
Rx: pediculide- dimeticone topical or permethrin topical.
2nd line mechanical removal (wet combing)
can use petroleum jelly as an occlusive.
impetigo.
Impetigo contagious, blistering skin infection. typically in children.
Staphylococcus aureus and Streptococcus pyogenes.
It has two forms: non-bullous and bullous. Bullae are fluid-filled lesions of >0.5 cm in diameter. single lesions often.
non bullous more common
RF: humidity, poor hygiene, chronic colonisation, prior skin disease
Mx: topical abx— hydrogen peroxide d-tds 3/52.
2’- mupirocin topical
Or fusidic acid.
if widespread, deeper or MRSA give oral.
complications: post strep glomurolonephritis
sepsis, cellulitis, osteomyolitis.
what is a melanocytic naevi
a benign mole
discuss melanoma
malignant tumour arising from melanocites.
most common cancer in young adults.
RF: sun exposure, FH, prev melanoma,
slight predisposition to male. fair skin, sunbed, increacing numbers of naevi, immunosupression. age.
may present as changing, bleeding etc
Ix: ugly duckling sign,
dermoscopy, biopsy- breslow indicator of prognosticity.
Rx: generally 99% cure rate with excision.
margin if confined to epidermis- 0.5-1cm
once 1cm need 2cm margin.
adjuvinant therapy- —pembrolizumab or nivolumab is stage 1-2.
stage 3-4— pembrolizumab + surgery (node etc)
17% get metastatic disease.
abcde assessment for melanoma + staging of melanoma
Asymmetry or lesion
Boarder irregularity, Bleeding
Colour variability
Diameter >6
Evolution – changing.
Breslow thickness
T1 if under 1mm
T2 1-2mm
T3 2-4mm
T4- >4mm + ulce
Add B to staging if an ulcer present.
necrotising fascitis
a severe life threatening skin infection.
bacteria introduced to skin- infection extends through fascia NOT into underlying muscle.
tracks along fascial planes– extends beyond area of cellulitis.
S+S: fever, tachycardia, hypotension– actions of bacterial toxins
severe pain– anaesthesia at site of infection. pedema and erythema- oedema byond erythema.
toxins cause microthrombi- occluding the soft tissue causing the cell death.
high mortality 10-40%.
types of nec fash
type 1 - polymicrobial by anaerobes- clostirium, e coli, klebsiella, proteus, enterobacter.
type 2- monobacterial – strep pyogenes. occ s aureus
other rarer ones- freshwater or saltwater/ oyster eposure etc.
Ix + Rx nec fash
Ix: clinical diagnosis- do not delay surg refferal.
innspection and debridement or-‘finger test’ performed at bedside (no resistance, no bleed, necrotic tissue + dishwater)
cultures is most specific.
Rx: rapid debridement
empirical abx therapy.
reconstructive surgery down the line.
discuss neurofibromatosis type 1
autosomal dominant genetic disorder.
progressive over lifetime.
leads to neuro defecits, motor delay, incoordination, vision/ school problems. gastro problems- very wide ranging and debilitating.
may be subtle if presenting young.
defining features: cafe au lait spots.
multiple neurofibromas
iris lisch nodules
RF: parent with NF-1
severe crush trauma (can lead to local neurofibromas)
Ix: MRI/CT for tumour imaging
PET scan
biopsy
ginetic testing for mutation confirmation
management of NF type 1
pheochromocytoma- (adrenal mass) – surgical removal.
generally surgical removal of tumours if possible.
generally patients die from malignancy
whole tumour removal by amputation is done.
can get additional chaemo.
discuss NF type 2
much more rare than type 1
tumours develop along the nerves- espechially vestibulochchlear
S+S: tinnitus, hearing loss, balance issues – all progressive. hallmark is that it is bilateral.
can get tumours in the brain.
autosomal dominant. can display mosaicism in 1 in 3.
Ix: symptom investigation
genetic testing.
Rx: symptomatically.
discuss eczema
dry itching skin, erythema, scaling, vesicles or lichenification.
can affect all age groups, but most commonly before 5y/o. 10-20% of children.
assoc with other atopic diseases.
RF: filaggerin gene mutation
<5
FH, allergic rhinitis, atopy.
Ix: clinical diagnosis.
consider IgE levels, skin prik testing, elimination diet.
Rx: 1st line- emmolients.
intermittent topical steds (hydrocortison topical 0.2-2%)
consider topical abx or oral abx.
2nd line- systemic immunosuppresive agent- pred, ciclosporin.
in chronic consider a topical cacineurin inhibitor: pimecrolimus or tac.
discuss pemphigus vulgaris
autoimmune condition- causing blistering of skin.
type 2 hypersensitivity. - ab’s against desmosones (1 and 2 proteins)
layers of skin seperate under attack and blisters form.
progresses- lesions enlarge and bahave physicologically like a burn.
mortality 5-15%- deemed potentially fatal.
RF: 50-60, women.
S+S: initially oral blisters. these then spread to other mucous sites + normal skin. spared soles and palms.
Nikolsky sign- (induction of blistering in normal skin) - indicative.
Ix: punch biopsy from site near blister.
Rx:
steds
rituximab
pemphigus vulgaris vs bullous phemphigoid
tombstoning on histology visible on PV.
PV split is between keratinocites and basal layer
BP- split occurs between epidermis and dermis.
