Dermatology Flashcards
What is a macule?
An area different in colour or consistency with no elevation
What is a papule?
Raised lesion <1cm diameter
What is a nodule?
Raised lesion >1cm
What is a plaque
Circumscribed, superficial, elevated plateau area
What is a vesicle?
Raised lesion containing fluid
What is a bulla
Large lesion containing fluid >0.5cm
Looks like a blister
What is a pustule?
Circumscribed lesion containing pus
May be white or yellow
What is an erosion?
Loss of epidermis that generally heels without scaring
What is an ulcer?
Deeper loss of epidermis/dermis
What is a patch?
Large area of colour change
What is the pathophysiology of eczema?
Immune response occurs due to exposure to irritants and allergens
This immune response leads to breaks the layers of the skin
Water leaks out and skin becomes dry and itchy
What factors can exacerbate eczema?
Stress Sweat Climate Foods House dust mite Infection
If atopic eczema is present in a child, will it progress to adulthood?
10-20% of children have it
Only 1-2% adults have it
As some children grow older, their skin disease may improve or disappear altogether, although their skin often remains dry and easily irritated
Which protein is mutated in 50% of cases of severe eczema?
Filggrin (FLG)
This is a protein in the epidermis which helps the layers to stick - loss of protein leads to break in the epidermal layer making it easier for irritants and allergens to enter the skin with resultant inflammation
In which area of the body is eczema more common?
Flexor surfaces
Note in infancy the cheeks is the most common place
What is eczema Herpeticum?
Herpes simplex virus infection of eczema areas of skin
Severe complication of eczema and may be life threatening
May be caused by being in contact with someone who has a cold sore
How do you spot the signs of eczema Herpeticum?
Areas of rapidly worsening painful eczema
Clustered blisters - that look like early stage cold sores
Skin erosions (Any skin that has broken away)
Possible fever
What are the life threatening complications of eczema Herpeticum?
Hepatitis
Encephalitis
Pneumonia
What is contact dermatitis?
A type of eczema
Due to a type IV hypersensitivity immune reaction
Either to an allergen e.g, latex, perfumes
Or to an irritant e/g, bleach, acid, pepper spray
What is linchenified skin?
Thickened skin which can be seen in areas of chronic eczema
What is the clinical picture of eczema?
Flexural surfaces Dry and cracked skin Red itchy scaly patches Can be weepy or blistered Skin can be linchenified (thickened) in chronic eczema
What is the management of eczema?
Conservative: Avoid triggers
Emollients: e.g, diprobase, epidermis
Steroid cream: mild hydrocortisone, moderate eumovate
For more severe eczema may consider phototherapy and systemic medication
What kind of emollients are available and where are they best used?
Creams - good for daytime use as they aren’t very greasy and absorbed quickly
Lotions - good for hairy or damaged areas of skin (weeping eczema) they are thin and spread easily
Sprays - for hard to reach areas
Ointments - these are more greasy, but good for very dry skin so good for night time use. Not to be used on weeping eczema
Soap substitutes - don’t foam like normal soap (remember to pat dry)
How often should emollients be applied in eczema?
As much as you like to keep skin moisturised
Ideally 3-4 times a day
How would you counsel someone on how to apply an emollient?
Apply generously
Use a clean spoon or spatula to remove from a pot or tub - this reduces risk of infections from contaminated pots
Be careful not to slip when using emollients in bath/shower or tiled floor - protect floor with a towel
Apply in a downwards motion
Apply after showering
Apply before steroids
What are calcineurin inhibitors?
Give some examples?
Immunemodulators used as an alternative to steroid therapy for eczema
They suppress the T lymphocyte response
Used as 2nd line treatments when you want to avoid the side effects of prolonged steroid use
Examples: tacrolmius, pimecrolimus
What is Dupilimab?
Immuneregulator
Antibody which inhibits the Th2 immune response
Approved for moderate to severe eczema
What is the pathophysiology of psoriasis?
Autoimmune skin condition
Where there is rapid turnover of skin cells (keratinocytes)
Cells only take 3-5 days to migrate to surface (normal cells take 23)
This causes hyperkeratosis - thickened skin and scaling
Leads to immature skin cells at the surface
What is the auspitz sign?
When the skin of psoriasis is scraped off it reveals dilating blood vessels underneath
This accounts for much of the erythema in psoriatic plaques
What is the clinical presentation of psoriasis?
Silver plaques - usually found on extensor surfaces
Scaling
Waxy appearance
Erythema
What are the psoriatic nail changes?
Nail pitting - small depressions in the nail
Subungal hyperkeratosis- chalky looking material under nail
Onycholysis - lifting of nail bed
Splinter haemorrhages - due to leaking of blood from capillaries
What are the different types of psoriasis?
Chronic plaques psoriasis (most common) - extensor surfaces
Flexural Psoriasis - seen in axilla, groin, and other skin folds
Pallmar plantar - lesions on palms and soles
Gluttate Psoriasis - plaques on trunk and limbs
Erythrodermic psoriasis - serious condition with confluence eczema effecting 90% of skin
What is the most common type of psoriasis?
Chronic plaque psoriasis
What infection usually precedes gluttate Psoriasis?
Sore throat - with associated group B strep
What age group does gluttate Psoriasis usually effect?
Adolescents
What are the triggers for Psoriasis?
Illness Stress Alcohol Smoking Infection - e.g, group B strep Certain drugs - lithium, beta blockers, antimalarials
What is the major risk factor for palmar planter psoriasis?
Smoking
What is the genetic basis for Psoriasis?
Inherited Th1 cell mediated disease
What is psoriatic arthopathy?
When patients with psoriasis also have arthritis in their joints due to the immune response
How is mild/moderate psoriasis managed?
Emollients
Coal tar (only to be used on stable Psoriasis) - can normalise keratinocyte growth patterns)
Calcipotrol - vit D analogues
Corticosteroids - to reduce inflammation
How is severe psoriasis managed?
Phototherapy - 2-3 times a week for 10 weeks (UV rays slow growth of keritonocytes)
Systemic treatment - methotrexate (immune modulator)
Give folic acid along side it
Biological agents - e.g, infliximab
What is the presentation of acne?
Papules
Pustules
Whiteheads (close comedomes)
Blackheads (open comodomes)
What is the pathophysiology of acne?
Inside hair follicles there is sebaceous glands (oil producing)
In acne an abnormal amount of oil is produced which can block the hair follicle
Blocked hair follicle becomes inflamed
Any harmless germs that live on skin surface can get trapped and exacerbate the situation
How can hormones effect acne?
Androgens can increase the size of sebaceous glands which increases the amount of oil produced
What are the different types of acne?
Acne vulgaris (most common)
Acne excoriee - where patient picks at skin and produces erosions
Infantile acne - seen in first few months of life
Acne fulminans - severe form seen in tropical climates
How is acne graded?
Mild - no scaring, a few small comedones
Moderate - no scaring, large close comedones
Moderately severe - some scaring, papular and pustular acne
Severe acne - severe scaring, nodules and cyst
What is the conservative lifestyle management for acne?
Avoid humid conditions
Diet - low sugar, low protein, low dairy. Lots of fruit and veg
Stop smoking - as nicotine increases sebum retention
Minimise face products - as oils and cosmetics can alter skin
Don’t scratch or pick lesions
Exposure to sunlight helps
How is mild acne managed?
Benzoyl peroxide face wash
Topical antibitoics - e.g, erythromycin solution or gel
Topical retinoids - eg, isotretinoin
How is moderate acne managed?
Benzylperoxide face wash Topical retinoids Antibiotics - e.g, tetracycline or doxyclicine 6-8 week course Oral contraception - can help with girls NSAIDs - short term use my help
What is the management for severe acne?
Oral isotretanoin
What must you counsel a girl on before starting oral isotretanoin
Works in 90% of cases - see improvement with 4-6 months
It is teratogenic
So make sure she is not pregnant and is using contraception
Must wait 3 months after finishing course to get pregnant
What is acne rosacea?
Characterised by facial flushing, persistent erythema, talangiestasia, inflammatory pustules and oedema
How is acne rosacea managed?
Avoid triggers - heat, hot food/drink, spicy food, alcohol, sunlight
Topical metronidazole
Oral antibiotics
What is actinic keratoses?
Rough scaly keratotic lesions on areas of exposed skin
Usually occur in patients who have worked outdoors
They are a precursor for skin cancer
How are actinic keratoses managed?
Liquid nitrogen - for individual lesions
5-FU cream - useful for large or multiple AKs, applied OD for 4-6 weeks
What is bowens disease?
Type of squamous cell carcinoma in situ
Only in epidermis with no dermis invasion
Seen on trunks or limbs
Well defined erythematous macule with slight crusting
Lesions enlarge slowly
Risk of developing SCC is 3-5%
How is bowens disease managed?
Excision, curettage and cautery
Cryotherapy
What is the appearance of a basal cell carcinoma?
Small papules that slowly grow
Lesions have pearly, shiny, translucent quality
Characteristic rolled edge
Have telangiectasia - dilated blood vessels near the surface of skin
What is the most common type of skin cancer?
Basal cell carcinoma
Where are the majority of squamous cell carcinomas found?
Head and neck
How can you tell the difference between a BCC and a SCC?
BCC - slow growing
SCC - rapidly growing, painful, markedly hyperkaratoic
What is the appearance of SCC?
Usually nodular with surface changes - crusting, ulceration, formation of cutaneous horn
Hyperkeratosis surfaces
What risk factors are specific for SCC?
Smoking
Chronic ulcers
Xederma pigemntosum - autosomal recessive condition that causes extreme sun sensitivity
Which types of SCC have poor prognosis?
> 2cm in size
Lesions on lip or ear
Invasion >4mm deep
Poorly differentiated cells
What is the medical name for a mole?
Melanocytic naevus
What is the ABCDEF for lesions?
A - asymmetrical
B - borders (regular or irregular)
C - colour (any variation, is it hyperpigmented)
D - diameter (>6mm (pencil rubber) is atypical)
E - evolution - has it changed, over what time period
F - family and friends (do others look similar)
What is a melanoma?
An invasive malignant tumour or melanocytes in the skin
What is breslow thickness?
Measures the distance in mm from the epidermis to the deepest layer of invasion in the dermis
How is eczema Herpeticum managed?
Admit to hospital
IV aciclovir
Which drugs can exacerbate psoriasis?
Lithium Beta blockers NSAIDs ACEi Anti-materials
What is the difference between a petechiae and a purpuric rash?
Petechiae - blanching macular <3mm
Purpura - raised blanching 3-10mm
