Dermatology Flashcards
How can you differentiate between SJS and TEN?
SJS = up to 10% skin involvement TEN = \>30% skin involvement
What is Nikolsky’s sign?
Epidermis separates with mild lateral pressure - secondary to adverse drug reaction
Which drugs are most likely to cause SJS?
Never Press Skin As It Can Peel
NSAIDs
Phenytoin
Sulphonamides
Allopurinol
IV Ig
Carbemazapine
Penicillins
How should SJS or TEN be managed?
Stop the cause
Transfer to ITU
IV Ig
Immunosuppression (eg ciclosporin and cyclophosphamide)
What is erythroderma?
Any rash involving >95% of the body
Recall 3 possible complications of erythroderma
Dehydration
High output heart failure
Infection
What is the cause of adult seborrhoeic dermatitis?
Fungus called malassezia furfur
What 2 skin conditions can be caused by malassezia furfur?
Seborrhoeic dermatitis
Pityriasis versicolor
What are the 1st and 2nd line options for treating scalp seborrhoeic dermatitis?
1st line = zinc pyrithione (‘head and shoulders’)
2nd line = ketocinazole
Which pathogen is the most common cause of impetigo?
Staphylococcus aureus
What are the 3 classes of impetigo and their respective management?
Localised, non-bullous: topical H2O2 1% cream / topical fusidic acid
Widespread, non-bullous: oral flucloxacillin or topical fusidic acid
Widespread, bullous: oral flucloxacillin
How long should children with impetigo be excluded from school?
Until lesions crusted over or 48 hours after antibiotics started
What are the lay terms for open and closed comedones?
Open = blackheads Closed = whiteheads
Recall some conservative management options for acne
Avoid over-cleaning face - bd with gentle soap is okay
Make up - use emollients and cleansers, non-comedonegenic preparations
Avoid picking and squeezing
How long should each acne medication be tried for to give it chance to work?
8 weeks
Recall the stepwise medical management of acne
Mild acne:
1st line: topical retinoid and or benzyl peroxide +/- topical clindamycin (which is never prescribed alone)
2nd line: azelaic acid 20%
Moderate (if not responding to topicals) acne:
- oral tetracycline + BPO/retinoid
OR
- oral COCP + BPO/retinoid
Dermatologist referral:
- Oral isotretinoin (roaccutane)
Once acne has cleared, how should this be maintained?
Topical retonoids and azelaic acid
What is Roaccutane?
Synthetic vitamin A
What pregnancy prevention plan should be in place for Roaccutane?
2 forms of contraception as it is very teratogenic
Recall some side effects of Roaccutane
Dry skin, raised triglycerides, hair-thinning, intracranial HTN, photosensitivity, low mood and suicidal ideation
What accumulated dose should you aim for with Roaccutane?
Body weight in kg x 100 mg
What is the progression of symptoms of rosacea?
1st = flushing 2nd = symmetrical facial rash with telangiectasia 3rd = persistent pustulopapular erythema
How should rosacea be managed?
Mild-moderate = topical metronidazole Severe = oral tetracycline
What is the aetiology of hidradenitis supparativa?
Chronic inflammatory occlusion of folliculopilosebaceous units that obstructs the apocrine glands and prevents keratinocytes from properly shedding the follicular epithelium
In lay terms, what is hidradenitis supparativa?
Abscesses that form near hair follicles in places where we tend to sweat more
What are the 2 biggest risk factors for hidradenitis supparativa?
Smoking and obesity
Rarely, what inflammatory disease is associated with
hidradenitis supparativa?
Crohn’s
How can hidradenitis supparativa be managed?
Conservative: weight loss, stop smoking, hygeine
Acutely: steroids PO, flucloxacillin, I&D
Chronically: topical clindamycin
What pathogen causes pityriasis versicolor?
Malassezia furfur
How does pityriasis versicolor appear?
Hypopigmented patches on trunk
Mild pruritis
How is pityriasis versicolor managed?
Topical ketoconazole
How does vitiligo appear?
Well demarctaed, depigmented skin patches usually affecting the peripheries
Recall some associations of vitiligo (don’t need to know in detail)
T1DM, Addison’s, autoimmune thyroid, pernicious anaemia, alopecia areata
How can vitiligo be managed?
Sunblock Topical corticosteroids (reverses changes if applied early)
What pathogen causes pityriasis rosea?
HHV-7
Describe the presentation of pityriasis rosea
Recent viral infection –> herald patch
Then erythematous, oval scaly patches
How should pityriasis rosea be managed?
It is self-limiting (6-12w) so no need
Broadly describe the 4 types of psoriasis
Plaque - most common, is well-demarcated red and scaly - affects scalp, back, extensors
Guttate - following a strep infection, “tear drop” lesions
Pustular - affects palms and soles
Flexural - skin is smooth
Recall some factors that exacerbate psoriasis
Trauma
EtOH
Certain drugs
Which drugs can exacerbate psoriasis?
INFLAME
Infliximab
NSAIDs
For HTN (beta blockers)
Lithium
ACE inhibitors
Malarial drugs
EtOH
How should chronic plaque psoriasis be managed in primary care? (give 1st, 2nd and 3rd line)
1st line: 4w trial of OM potent corticosteroid and ON vitamin D analogue
2nd line: after 8w (so 4w break): OM potent corticosteroid and BD vitamin D analogue
3rd line: 4w trial of BD potent corticosteroid OR coal tar
Use emollients as an adjunct
What is the maximum duration of use of topical potent and very potent steroids before a break is needed?
Potent = 8w
Very potent = 4w
How can chronic plaque psoriasis be managed in secondary care?
Phototherapy/photochemotherapy Systemic immunosuppression (eg infliximab, etanercept, ustekinumab)
Describe the distribution of eczema in infants vs children vs young adults
Infants: face and trunk
Child: extensors
Young adult: flexures