Dermatology notes Flashcards
% staph aureus carriers
% in people with atopic dermatitis
20%
80%
what type of light does what for vitamin D synthesis in skin
UV-B light forms vitamin D3 from cholesterol
What is the required amount of time to create your daily amount of vitamin D?
About 20 minutes of sunlight over 20% of their body surface (longer does not make more)
What is pitted keratolysis
Mx
Overgrowth of corynebacteria in warm wet most environment which causes very superficial punched out lesions. Is sometimes symptomatic.
Tx = topical clindamycin/oral erythromycin
Erythrasma
Mx
Overgrowth of corynebacteria in warm wet most environment which causes red/brown discolouration. Is sometimes symptomatic. Becomes coral coloured due to birefringence under special Wood’s lamp.
Tx = topical clindamycin/oral erythromycin
furuncle vs carbuncle
Mx
If it has a single ‘head’ it is a furuncle (boil), if it has many heads it is a carbuncle. Usually staph aureus.
Mx = fluclox
erysipelas vs cellulitis
Mx
Usually systemically unwell with preceding flu-like illness. Leg is a common place for cellulitis. Can be staph or strep. Erisipelas is usually more superficial and on the face, whereas cellulitis is deeper and on the leg.
Mx = amoxicillin or coamox if very severe
time course of primary and secondary syphilis
Primary chancre
Secondary syphilis: 6-10 weeks later papulosquamous eruption often involving palms and soles
lyme disease organism
spirochete bug Borrelia burgdorferi
clinical course of lyme disease
• A tick buries its head in the person and it carries the spirochete bug Borrelia burgdorferi. It causes:
o Early features
♣ Erythema chronicum migrans = small papule at site of tick bite that develops into a large annular lesion with central bull’s eye.
♣ Systemic flu-like symptoms
o Late features
♣ CVS: heart block, myocarditis
♣ Neurological: cranial nerve palsies, meningitis
♣ Polyarthritis
two types of leprosy
Which has more bacilli around
- Tuberculoid leprosy – affects nerves (anaesthetic areas) and skin (hypopigmented areas) and has few mycobacteria bacilli around
Lepromatous leprosy – thickened facies, macules, papules, nodules, plaques and has lots of mycobacteria bacilli around
What does mycobacterium marinarum present like?
Recent contact with tropical fish tank causing inoculation of bacteria into hand. Causes red scaly plaque on hand which travels up the arm lymphatics causing clusters of lesions as it does so.
molluschi contagiosi in adults?
Yes, but worry about immunosuppression
pediculosis
lice (head, pubic etc)
incidence peaks of psoriasis
20s and 50s
genetic influence of psoriasis
PSORS1 and PSORS9
drugs from lecture that trigger psoriasis
beta blockers
lithium
interferon
withdrawal of steroids
Auspitz sign
when you pick at it, it bleeds.
Happens in psoriasis2
clinical picture of pustular psoriasis
Can be generalised or palmar-plantar. Has pustules and is tender. Can be systemically unwell.
Management steps in psoriasis:
GP and dermatologist
GP:
- emollient + vitD analogue + steroid (morning then night)
- vit D BD
- steroid BD or other stuff like coal tar or dithroanol
Dermatologist:
- light therapy
- immunosuppression
- biologics
what is psoralen
a photosensitiser you put on the skin before UV-A light therapy = PUVA therapy
Good for well demarcated psoriasis (e.g. palmar plantar)
when are you eligible for biologics for psoriasis?
Severe:
PASI >10 (psoriasis scale)
DLQI >10 (QoL dermatology scale)
and
failed methotrexate/ciclosporin
2 ways to get urticaria (ppathophysioligcally)
- IgE and histamine release
2. Direct degranulation of mast cells - can be physical stimuli or ASPIRIN
wheal vs angioedema
wheal = superficial and resolves in minutes to hours
angioedema = in dermis and submit tissue and resolves in 72 hours
Mx of anaphylaxis (know doses)
500ug adrenaline
200mg hydrocortisone
10mg chlorpheniramine
Oxygen
acute vs chronic urticaria
Acute is <6 weeks and is common in children. Chronic is >6 weeks with daily or episodic wheals and is common in middle aged women, usually lasting 2-5 years.
most common causes of acute urticaria
- Idiopathic (50%)
- URT infections (40%)
- Drugs – e.g. aspirin (10%)
- Food – e.g. shellfish, nuts, fruit (<1%)
most common causes of chronic urticaria
idiopathic
physical things like pressure, cold, heat, water, vibration, dermographism
autoimmune
urticaria management
- avoid triggers
- H1 antagonist (antihistamines)
♣ Sedating type at night (chlorpheniramine)
♣ Non-sedating type during day (cetirizine) - H2 antagonists
♣ Ranitidine (since pathophysiology involves H1 and H2 activation)
chronic –> omalizumab
severe acute –> 4/5days pred
main thing to exclude in history of urticaria
anaphylaxis - so ask about chest tightness/trouble breathing
In atopic dermatitis (eczema), what can you give instead of steroids if you’re worried about thin skin
A protopic (calcineurin inhibitor e.g. tacrolimus)
eczema - what helps lichenified skin
salicylic acid
seborhoeic dermatitis in adults Mx
ketoconazole +/- hydrocortisone
as malasezia furfur playa a role
pompholyx
itchy vesicular rash on hands on feet, common in hot months. also called dyshidrosis.
discoid eczema presentations
round red patches on back of hands in 60-70 year old
Asteatotic eczema
Common in elderly where you get a crazy paving appearance of the cracks in the skin surface. Most commonly on shins. More common in the winter. Needs lots of emollients.
acute eczema
Rapid onset ill-defined redness, swelling with scaling, papules and vesicles. Vesicles burst causing exudate and crusting.
lichen simplex
Isolated patch of lichenification due to repeated scratching or rubbing. Manage by getting patient to stop scratching. 4
morphemic bcc
Atypical BCC that is skin coloured and doesn’t heal. Take home message is that it doesn’t look right and isn’t healing so you need a biopsy
Micrographic surgery
Glasgow 7 point checklist
A checklist to determine risk of lesion being a melanoma:
size change
shape change
colour change
> 6mm diameter
inflammation
oozing
change in sensation
margins for melanoma
2mm margin first
then
Margin in 2nd stage depends on Breslow thickness:
0-1mm 1cm
1-2mm 1-2cm
2-4mm 2-3cm
>4mm 3cm
\+/- sentinel lymph node biopsy
margin in SCC
<2cm, 4mm margin
>2cm, 6mm margin
Cosmetically important, Mohs
how do efudix and aldara work
Efudix = 5-FU, fluorinated uracil gets taken up into cells can causes cell cycle arrest
Aldara = imiquimod and kick starts immune system to attack abnormal cells
What is pomade acne
Pomade is a non-medical word for a scented ointment or dressing for the hair. Pomade acne is when some of this ointment gets onto the forehead and contributes to acne because it is comedogenic.
How does steroid-induced acne look different
o You don’t get comedones. It is not the same pathogenesis as acne vulgaris as described above
o It is highly inflammatory with many papules and pustules
o It is monomorphic (all lesions look similar)
What is acne fulminans?
The worst end of the spectrum of acne. Widespread nodular and cystic appearance and can be quite explosive in onset and appear over a couple months. Patients can be quite systemically unwell (arthralgia, fever), thought to be from a hypersensitivity reaction to P. acnes. This is one of the rare times you would use a short course of steroids to treat acne.
What is acne conglobata?
A form of acne where you get deep and very tender cysts. It describes a subset of very severe acne.
what 2 metabolic syndromes cause acne
PCOS
CAH
When should you review a patient with acne after starting or changing treatment
2m
Acne vulgaris treatment escalation
Avoid comedogenic makeup/sunscreen. Advise not related to food or hygiene
1st line = benzoyl peroxide + topical clindamycin/topical retinoids. Wait a month.
2nd line = add the third. Oral COCP may be tried in women
3rd line = add oral lymecycline/doxycycline
4th line = oral isotretinoin with dermatologist
Refer anyone at any point for oral retinoids with scarring acne +/- severe acne
Yes of isotretinoin (roacutane)
side effects of isotretinoin include: dry skin/eyes/mouth, nose bleeds, photosensitivity, teratogenicity (need 2 forms of contraception), low mood, raised triglycerides (needs monthly blood tests), hair thinning
instead of topical clindamycin and oral lymecycline, what Abx do you use in pregnancy?
erythromycin.
and don’t use topical retinoid
polyarteritis nodosa:
- size of vessel
- painful?
- cutaneous sign
- pathogenesis
- associated condition
- autoantibody
- medium vessel
- very painful
- lived reticularis
- IgM and C3 in vessel walls
- Hep B
- pANCA
does sun make SLE better or worse
WORSE - key symptom
rash in:
- acute lupus
- subacute lupus
- chronic lupus
acute = butterfly rash with nasolabial sparing
subacute = nonindurated annular lesions that don’t scar
chronic = discoid lupus with scarring annular lesions
important condition to exclude if someone presents with dermatomyositis
cancer. malignancy in 30%!
wounds in which age group heal the best and worst:
adults
embryos
children
embryos heal without scarring (best)
children heal with excessive scarring (worst)
adults have slower healing but better scar
skin changes in venous insufficiency (4)
- haemosiderin staining
- atophie blanche
- lipodermatosclerosis (inverted champagne bottle)
- ulceration
venous ulcer location
medial malleolus
associations:
- erythema nodosum
- pyoderma gangrenosum
erythema nodosum = IBD + sarcoid
Pyoderma gangrenosum = IBD + RA
types of nec fash, causes and treatment
type 1 = polymicrobial = vancomycin and tazocin
type 2 = strep pyogenes = benzyl pen + clindamycin
All IV
Name 3 emollients in terms of oiliness
Least oily = diprobase
Middle = epaderm
Most oily = 50/50 liquid parafin:white soft paraffin
In what body areas are steroids more effective
In occluded areas like armpit and natal cleft
lichen simplex
Thick skin due to chronic itching. can be from many things, including eczema
which UV therapy has more chance of causing cancer
PUVA»_space; UVB
Yes of methotrexate
liver fibrosis, lung fibrosis, hair loss, bone marrow suppression, N&V, teratogenic. Must use folate alongside.
Unilateral hand dermatitis cause
Probably fungal (single hand eczema is very rare)
