WEEK 2 Flashcards
advantages of topical treatments?
- direct application
- reduced systemic effects
disadvanates of topical
tim consuimgn
correct dosage
what is a cream?
- semisolid of oil in water
- contain emilsifier and preservative
- non greasy
- high water content
- cool and moisturise
what is an ointment?
- semi solid grease/oil
- no preservative
- occlusive and emollient
what is a lotion?
- liquid formualtion
- suspension or solution of medication in water, alcohol or other liquids
- treat scalp or hairy areas
what is a paste?
- stiff
- greasy
- contain finely powdered material
- protective, occlusive, hydrating
advantage of using a foam?
- increased penetration of active agents
- can easily spread over large areas of skin, no greasy oil/film
main classes of topical therapies?
- emollients
- topical steroids
why re emollients used?
- prescribed for all dry scaley conditions
- enhance rehydation of epidermis
- need frequent application
how much emollient should be prescribed per week?
300-500g per week for extensive asthma
- apply frequently
what is one risk when using an emollient?
highly flammable
- smoking is not reccommended
what is the term given to very dry skin?
xerotic
give 4 possible side effects of topical steroids
- v
mode of action of topical steroids?
- reduce inflammation
- cause immune suppression
- vasoconstrictive
- anti proliferative
give a mild topical steroid?
hydrocrotisone
give a name of a potent steroid?
- betnovate
- mometasone
- valerate
- betamethasone
uses of topical steroids?
- eczema
- psoriasis
- other non-infective inflammatory dermatoses
- keloid scars
how much steroid should be applied to the whole body?
20-30g tube for one week
side effects of topical steroids?
- steroid rosacea
- perioral dermatitis
- thinning of the skin
- purpura
- stretch marks
- may worsen or mask infections
- systemic absorption
- tachyphylaxis
- rebound flare of disease
- glaucoma and cataract
name an ultra potent steroid
clobetasol propionate
what effects do antiseptics have?
- bacteriocidal affects
give an example of an antiseptic
- providone iodine skin cleanser (betadine)
- hibitane, savlon
- triclosan
- hydrogen perooxide
when would antibiotics be used?
- acne/roascea
- skin infection
- infected eczematous process
- otitis externa
name conditions in which topical antifungals would be used
- candida (thrush)
- dermatophytes (ringworm)
- pityriasis versicolour (use cream or shampoo)
name some good antipruritics
- menthol
- capsaicin (from red chilli peppers)
- camphor / phenol
- crotamiton
what are keratolytics used for?
used to soften keratin
e.g….
- viral warts
- hyperkeratotic eczema / psoriarsis
- corns / calluses
side effects of topical therapies?
- burning or irritation
- contact allergic dermatitis
- local toxicity
- systemic toxicity
what cell type lines the normal epidermis?
- epidermis-stratified keratinising squamous epithelium
function of langerhans cells in epidermis?
- act as sentinels monitoring environment for antigens
- important in initiating inflammation
- located in upper and mid-epidermis
- dendritic cells
which part of the dermis are the appendages and pilosubaecous usints found?
in the reticular dermis
where are the malnocytes?
the purple dots with the white halos around them
- highly dendritic
- pigment synthesisers
- act as a UV barrier
what is acanthosis?
increased thickness of the epithelium (to basal layer) really just hyperplasia
what is parakeratosis?
perisistence of nuclei in the keratin layer
what is hyperkeratosis?
increased thickness of keratin layer
what is papillomatous?
irregular epithelial thickening
what is spongiosis?
- oedema fluid between squames appears to increase prominence of intercellular prickles
- if severe filled by oedema flui will develop
what are the 4 main recation patterns of inflammatory skin disease?
- spongiotic intraepidermal oedema (e.g. oedema)
- psoriaform-elongation of the rete ridges (e.g. psoriasis)
- lichenoid-basal layer damage (e.g. lichen planus and lupus)
- vesiculobullous-blistering (e.g. phemphigoid, phemphigus and dermatitis herpetiformis)
- conditions characterised by damage to the basal epidermis
- protypic condition is lichen planus
- itchy flat topped violaceous papules
lichenoid disorders
what does lichen planus histology look like?
- irregular saw tooth acnthosis
- hypergranulosis and orthohyperkeratosis
- band like upper dermal infiltrate of lymphocytes
- basal damage with formation of cytoid bodies
- blisters are the primary feature of this disease
- caused by disroders of the immune system
Examples
- pemphigus
- bullous pemphigoid
- dermatitis herpetiformis
immunobullous diseases
pathology behind pemphigus?
loss of integrity of epidermal cell adhesion
what is pemphigus vulgaris?
- autoimmune condition
- IgG auto-antibodies made against desmoglein 3 (like a glue in the eoidermis)
- immune comlexes form on cell surface disrupting desmosome attachments
- end result is acantholysis
symptoms of pemphigus vulgaris?
- involves skin (scalp, face, axillae, groin, trunk)
- may affect mucosa (e.g. mouth, resp. tract, extensive mucosal involvement may be fatal)
- produces fluid filled blisters which rupture to form shallow erosions
what is the histological hallmark for dermatitis herpetiformis?
- papillary dermal microabscesses
what antibody should be looked for in dermatitis herpetiformis?
IgA in dermal papillae
give the aetiology of acne?
- increased androgens at puberty
- increased androgen sensitivity of sebaceous glands]keratin plugging of pilsubaecous units
- infection with anaerobic bacterium corynebacterium acnes
what is rosacea?
- scaley erythamatoeus eruptions
- patchy inflammation with plasma cells
- pustules
- demodex mite in subaecous duct
type 1 allergy
- causes an immediate reaction (minutes - 2hrs)
- may routes of exposure
- must have a consistent reaction with every exposure
what must occur with all allergies
you must be sensitised to the allergy first
common clinical presentations of allergies?
- urticaria
- angioedema
- wheezing/asthma
- anaphylaxis (circulartory collapse)
investigations of allergies?
- history
- specific IgE
- skin prick or prick prick testing
- challenge test
- serum mast cell tryptase level
manageeent of allergies?
- allergen avoidance
- orevent affects of mast cell activation (anti-histamines)
- anti-inflammatory agent (corticosteroid)
- adrenaline autoinjector (for anaphylaxis)
type IV allergy
- delayed hypersensitivity
- antigen specific
- T cell mediated
- allergic contact dermatitis
- onset reaction typically 24-48 hrs after exposure
what is done when bacteria is suspected?
put swab on agar plate
- gramp oisitive cocci in clusters
- aerobic and faculatively anaerobic
- 2 important ypes (staph. arueus: coagulase positive + coagulase negative staph)
staphylococcus sp.
only ever prescribe or take a swab when???!!
THERE IS A CLINICAL SIGN OF INFECTION
- dont assume just because there is a culture swab carried out
- common human pathogen
- prodces enzymes including coagulase, an enzyme that clots plasma
- distinguishes it from all other staph. species^^
- causes wound, skin, bone and joint infections
- flucloxacillin reccommended to treat
- resistent starins (methicillin resistant)
- some strains produce toxins
staphylococcus aureus
what does methiccilin resistent staph aureus mean?
flucloxacillin resistent
use e.g.
- doxycycline
- co-trimoxazole
- vancomycin
what does it mean by staph. epidermidis being a skin commesnal?
NOT PATHOGENIC
when should yu swab a leg ulcer
when there is high suspcicion of infection as there are usually commensals living there whcih is okay
what happens if you think a patient has measles?
in negative pressure room
need to be isolated
what is urticaria?
erythema with a well defined edge
what does eczema look like?
ill defined, scaley
give 3 cutaneous examples of type 1 hypersensitivity
- urticaria (red wehals caused by blood vessel dilation + leakage into surrounding tissue)
- angio-oedema (swelling of subcutaenous tissues)
- anaphylaxis
cutaneous examples of type 4 (delayed) hypersensitivity?
give the factors increasing the potential of topical steroids to cause side effects
side effects of steroids?
- contact allergy to hydrocortisone
- acneifrom eruptions
- tachyphylaxis
- pigmentary changes
- poor wound healing
- modification of existing disease
- unstable pustular psoriasis
- steroid roascea
- atrophy, bruising
- gaucoma
- hirsutism
- poor owund healing
- striae (stretch marks)
- growth retardation (systemic effect)
what can be done to reduce the risk of side effects from steroids?
- dont use topical steroids where they wnt work
- use least potent preparation that is effective
- know quanitites required for appropriate use
