Dermatology Flashcards
Give the pathophysiology of acne vulgaris?
Acne is caused by chronic inflammation with or without localised infection in the pilosebaceous unit.
Acne results from increased production of sebum, trapping of keratin and blockage of the piloseaceous unit.
Why is acne exacerbated by puberty?
androgenic hormones increase the production of sebum, and it improves with anti-androgenic hormonal contraception.
Which bacteria is felt to be the most important in acne vulgaris development?
Propionibacterium acnes bacteria as it colonises the skin. excessive growth of this bacteria can exacerbate acne and many treatments aim to reduce these bacteria.
What are the terms used to describe lesions in acne vulgaris?
Macules: flat marks
Papules: small lumps
Pustules: small lumps with yellow pus
Comedones: skin coloured papules representing blocked pilosebaceous units
Blackheads: open comodones with black center
Ice pick scars
Hypertrophic scars: small lumps that remain after lesions heal
Rolling scars: irregular wave-like irregularities after lesion heals
What is the management of acne vulgaris?
treatment is based on a stepwise fashion:
- no treatment if mild
- Topical benzoyl peroxide reduces inflammation, helps unblock skin and is toxic to P. acnes bacteria
- topical retinouds slow production of sebum
- topical antibiotics
- oral antibiotics
- COCP
- isotretinoin in a last line effective option (oral retinoids)
Describe the usage of isotretinoin in acne vulgaris
It is a retinoid and works by reducing the production of sebum, reducing inflammation and bacterial growth.
Can only be prescribed by a dermatologist as is teratogeic.
What are the side effects of isotretinoin?
- dry skin and lips
- photosensitivity
- depression, anxiet, aggressiona nd suicidal ideation
- rarely SJS and toxic epidermal necrolysis
What is the pathophysiology of arterial ulcers
Occurs due to poor blood supply to the skin due to peripheral arterial disease
What are the distinguishing features of an arterial ulcers?
Absent pulses Pallor Tend to be smaller More regular boarder Grey colour due to poor blood supply Less likely to bleed More painful than venous ulcers Pain at night when legs elevated Pain worse on elevating the leg, improved by hanging
What is the management of arterial ulcers?
- Treating underlying cause
- Good wound care (debridement, cleaning, dressing, abs)
- Tissue viability nurse and district nurse input
- plastic surgery input
What is eczema?
It is a chronic atopic condition caused by defects in the skin barrier leading to inflammation in the skin.
There is a genetic component to eczema however there is no single inheritance pattern.
What is the presentation of eczem?
Usually presents in infancy with dry, red, itchy and sore patches of skin over the flexor surfaces and on the face and neck.
Patients experience periods of flares
What is the pathophysiology of eczema?
Tiny gaps in the skin barrier provide entrance for irritants, microbes and allergens that create an immune response resulting in inflammation and associated symptoms
What is the management for eczema?
EMOLIENTS!!!
Flares can be treated with thicker emollients, topical steroids and treating complications such as infections.
Specialist treatments include:
- zinc impregnated bandages
- topical tacrolimus
- phototherapy
- systemic immunosuppressants
What is the role of topical steroids in eczema?
General rule: weakest steroid for the shortest period required.
SE:
- thinning of the skin
- lead to more flares
- bruising
- tearing
- stretch marks
- telangiectasia
What is the steroid ladder used in eczema?
Mild: Hydrocortisone 0.5%, 1% and 2.5%
Moderate: Eumovate (clobetasone butyrate 0.05%)
Potent: Betnovate (betamethasone 0.1%)
Very potent: Dermovate (clobetasol propionate 0.05%)
HELP EVERY BABY DERMATOLOGIST
What is the most common bacterial infection in eczema?
Staph aureus which is treated with flocloxacillin.
What is Eczema herpeticum?
Viral skin infection in patients with eczema caused by the HSV or VZV.
What is the presentation of eczema herpeticum?
Patient with eczema develops:
- widespread, painful vesicular rash
- with systemic syx such as fever, lethargy, irritability and reduced oral intake.
- lymphadenopathy
What is the management of eczema herpeticum?
Tx usually started based on clinical appearance.
Aciclovir. Mild or moderate = oral whereas more severe = IV aciclovir.
How is eczema herpeticum diagnosed?
Viral swabs of the vesicles can be used to confirm diagnosis but treatment is started based on clinical appearance.
What is basal cell carcinoma?
The most common form of skin cancer but metastasis is rare as they are slow growing.
What are the risk factors for basal cell carcinoma?
- fair skin
- sun exposure
Describe the presentation of basal cell carcinoma
Typically: pearly nodule with a raised, red edge. May be scaly. Often on the face.