Pharmacology - Dermatology Flashcards
Eczema: prevalence, symptoms, consequences
- common esp in children >3yo
- redness
- scaling and dryness
- thickening of skin (lichenification)
- itchiness (pruritis)
- scratching leads to breaking of skin (excoriations)
- can get vesicles (blistering if allergic)
- can get infected (bacterial)
-can be occular (in eye)
Eczema aim of treatment and treatment
reduce itching to reduce scratching
emollients
topical steroids
Atopic eczema/dermatitis: meaning, causes, management
Irritant contact dermatitis
ex: washing hands frequently, cheap jewelry
avoid irritant
treat with emollient
Allergic contact dermatitis: consequence and treatment
-can cause blistering
treat with emollient and topical steroid (hydrocortisone)
Psoriasis: what is it, how does it look like, common places, consequences
auto-immune disease
red, flaky, crusty patches with silvery scale
areas with more movement (elbows, knees, scalp etc.)
common behind ears, around hairline and in umbilicus
can be nail (depressions in nails, thickening of nails, separation from nail bed)
and joint involvement
fissures in skin
can get infected
Psoriasis treatment
First line:
- emollients
- vit D analogues (paricalcitrol) +/- potent topical steroids
- coal tar
- topical steroid monotherapy only in specific conditions (sensitive skin areas, thick skin sites such as palms)
- Dithranol in hospital
- topical retinoid (usually intolerated in psoriasis patients)
- shampoos for scalp psoriasis
- NEVER oral steroid
Second line:
- phototherapy
- acitretin
- immunoppressants (ciclosporin etc.)
- biological agents
ADR dermatitis example
amoxicillin
differential diagnosis
eczema: ill defined
psoriasis: well defined red plaques
eczema: itchiness
cellulite: discomfort
treatment of yeast caused eczema
antifungal (metronidazole)
topical steroid
cradle cap
neonate eczema
ignore
if severe: emollients
Infected eczema
antibiotics
Best emollient
patient’s preference
Topical steroid potency examples
mild–> 1% hydrocortisone
moderate–>clobetasone butyrate
potent–> betamethasone valerate
very potent –> clobetasone propionate
Topical steroid use
in bursts (ex: week or 2 when condition happens): breaks important to avoid insensitivity
once daily
affected areas only
do not apply sparingly
Fingertip unit
1 fingertip –> are of 2 palms –> approx. 0.5 g
whole body –> 100 g < 1 week
if topical steroids do not work…
topical calcineurin inhibitors (avoid sun to prevent cancer but no real evidence)
phototherapy
immunosuppression
alitretinoin (retinoid)
Pitfalls in psoriasis
steroid tachyphylaxis
-dec gradually
Drugs that exacerbate psoriasis
- beta-blockers (no need stop but if starting, choose alternative)
- lithium
- interferon
Acne causes
- increased sebum secretion
- blocked pores
- colonisation with P. acnes
- inflammation
-NOT: poor hygiene not drinking enough water eating too much chocolate masturbation
Features of acne
non-inflammatory lesions:
-open and closed comedones
inflammatory lesions:
- pustules
- papules
- nodules
scars
comedones treatment
topical retinoid
topical acne treatment
benzoyl peroxide
- most effective OTC
- bleach clothes
- irritant, proper use
- only on affected area
- no bacterial resistance
azelaic acid
-gentler than benzoyl
retinoids
- ex: adapalene
- irritant
- use in severe cases
antibiotics:
-ex: duac (clindamycin + benzoyl peroxide) in combination with retinoid
systemic acne treatment
- antibiotics (ex: erythromycin in pregnancy)
- oral contraceptive pill if acne gets worse around period (progesterone-only pills/mini-pills can raise androgen levels and exacerbate-rebound, long time to settle after withdrawal)
- isotretinoin (monitor LFTs, avoid in pregnancy, can cause dry skin, use lip balm, mental complications?)
acne scars
permanent depressions
raised lesions can be treated with steroid injections but not very effective
Rosacea treatment
azelaic acid in Finacea
topical metronidazole
isotretinoin (often recur)
Urticaria Features
wheel shaped oedema
no scaling
typically itchy (pruritus) ex: chicken pox
lesions last <24 hours
resolve without marks
Urticaria types
acute
-easily identifiable trigger
chronic
Urticaria treatment
crotamiton (?)
calamine (soothing) for itching
antihistamines (5x the licensed dose):
non-sedating at morning and sedating at night
if fail… H2 blocker (ranitidine) or LT blocker
if fail…. short term immunosuppression
omalizumab (not licensed for urticaria yet)
Urticaria causes
morphine (displace histamine from mast cells)
nettle stings/insect bites (oral antihistamine / topical 1% HC)
physical stimuli (ex: uv light, scratching, pressure such as belts and tight shoes)
Drug Exanthems
- typically 1-2 weeks after drug started (even if drug stopped)
- low grade fever
- stop drug and allow settle over 2 weeks
- start on trunk
- mildly pruritic
Drugs that cause eruptions
- anticonvulsants
- sulfonamides
- penicillins
- cephalosporins
- NSAIDs
- allopurinol
Photosensitising drug
- doxycycline
- NSAIDs
- diuretics
- phenothiazines
- retinoids
- sulphonylureas
- quinine
- amiodarone
Fixed drug eruption
most common on genitalia
Steven-Johnson syndrome
- rash, fever and respiratory systems
- 2 or more mucosal sites
- prolonged course
Skin failure
often painful: analgesia
Skin bacterial infection causes
- mostly S. aureus or Group A Strep
- co-infection may occur
Skin bacterial infection treatment
antibiotics
topical antiseptics
Skin bacterial infection examples
- impetigo
- bacterial folliculitis
- cellulitus
Cellulitis treatment
penicillin / benzylpenicillin
prophylaxis
bacterial folliculitis treatment
topical antiseptics orqal antibiotics (flucloxacillin,doxycycline etc.)
Viral infections of skin (virus examples)
- herpes simplex (cold sores)
- varicella zoster (chickenpox)
- human papilloma virus (HPV)
- molluscipox virus
Herpes simplex treatment
acyclovir when tingling before visible symptoms
Chickenpox features
- milder in children
- fever
- blisters
- remain dormant in ganglion after infection and can re-emerge as shingles
Chickenpox treatment
no need unless severe (immunospressed patients): acyclovir
Shingles
- herpes zoster
- caused by voricella zoster
- triggered by stress, weakness etc.
Viral worts
- papilloma virus (HPV)
- surgical intervention
- OTC: salycilic acid
- can resolve on their own
- duct tape for 6 days, breathe 1 day and repeat, helps soften
Molluscum contagiosum
- papules with central depression
- contagious
- more common in eczema patients
Molluscum contagiosum treatment
self limiting
surgical intervention
cryotherapy
hydrogen peroxide cream
Dermatophyte genera
Microsporum
Trichophyton
Epidermiphyton
Dermatophyte transmission
anthropophiliac (human)
zoophilic (animal)
geophilic (soil)
Tinea pedis treatment
local:
topical antifungal
Daktarin (miconazole)
extensive: oral antifungal (ex: terbinafine)
Tinea corporis
Body ringworm
Tinea capitis
scalp
hair loss
MUST oral antibiotic
if inflamed: topical steroid
Tinea unguium/Onychomycosis
nail fungal infection
clinically very similar to psoriasis
MUST oral antifugal
nail lacquer
Candidiasis versicolor
- hypopigmented patches of skin
- sweating
- asymptomatic aside from appearance
Candidiasis versicolor treatment
ketoconazole shampoo as body lotion
Infestations
scabies mites:
- homes/army barracks/prisons
- treat everyone
- burrows
- penile papules
Scabies treatment
Scabicide:
- babies (whole body inc. scalp)
- adults (neck down)
- Permethrin (leave on for 8-12 hrs)
- Malathon (leave for 24 hrs)
- Treat on days 1 & 8
- Treat everyone simultaneously to prevent re-infection
Hair lice transmssion
- transmitted through hair-to hair contact
- can transmit bacteria
Hair lice treatment
removal:
- wet combing
- days 5, 9 and 13
shave head
occlude with mosituriser
Pediculicides (target live lice NOT eggs):
- Dimeticone
- Malathion
- 2 applications 7 days apart
Warning signs of cancer
Pigmented lesion:
- enlargement
- colour change esp. darkening
- change in shape
- asymmetry
- itching
Non-pigmentes lesion:
- enlargement
- asymmetry
- recurrent scabbing
- bleeding
ABCDE rule
Asymmetry Border Colour Diameter (>6 mm) Elevation
2 or more –> lesion suspicious
Dysplastic moles
- potential to become malignant
- bigger and more irregular border
Seborrheic keratosis
- not suspicious
- well defined and brown
- look stuck on
Campbell de Morgan spots
- red moles
- harmless
Bowen’s disease
- very early form of skin cancer
- easily treatable
Squamous cell carcinoma
- look like volcano with crater
- refer
basal cell carcinoma
- pearly/shiny surface
- central depression with scab/crest
- refer
Dermatitis vs. eczema
Dermatitis: skin inflammation in general
Eczema: chronic case of dermatitis
