Clinical Dermatology Flashcards
Which areas do psoriasis most commonly affect?
Extensors
What is the most common type of psoriasis?
Psoriasis vulgarise (chronic plaque psoriasis)
What are the main topical treatment soptions for psoriasis?
Emollients plus vitamin D analogues (calcipqotriol/calcitriol), coal tar, dithranol, steroid ointments (and possible phototherapy)
What are the systemic treatments possible for psoriasis?
Retinas, immunosuppression (methotrexate/ciclosporin), immune modulators
Which bacteria are involved in acne?
P. acnes
Of whiteheads and blackheads, which are open and which are closed?
Whiteheads - closed and blackheads - open
What are the topical treatments for acne?
Benzoyl peroxide (keratolytic/antibacterial), topical Vit A deravitives (retinoids) and topical antibiotics
What systemic treatments are available for acne?
Antibiotics and oral retinoids (isoretinoin)
What are the side effects of oral retinoids eg. isotetinoin?
Depression, dry skin and teratogenicity
What are the characteristics of rosacea?
Flushing of the central face along with papule, pustules and erythema (NO comedones)
What are the treatments of rosacea?
Topical metronidazole, isoretinoin if severe, vascular laser for telangiectasia
What is the treatment for lichen planus?
Topical steroids (oral if extensive)
What is the appearance of lichen planus?
Violaceous (pink/ purple) flat-topped shiny papules
How are bullies pemphigoid and pemphigus differentiated?
Bulls pemphigoiD split is Deeper (through DEJ), which pemphiguS is more Superficial
Positive Nikolsky sign
Positive result: the top layers of the skin slip away from the lower layers when slightly rubbed
How can BP and pemphigus vulgarise be differentiated clinically?
BP is negative for Nikolsky sign while pemphigus vulgarise is positive
What is the investigation for Pemphigoid disorders?
immunofluorescence
What is involved in the acute phase of eczema/dermatitis?
Papulovescular erythematous lesions, oedema, scaling and crusting
What is involved in the chronic phase of eczema/dermatitis?
Thickening (lichenification), elevated plaques and increased scaling
What is common to both the acute and chronic phase of eczema/dermatitis?
Itch
What is the pathophysiology of contact allergic dermatitis?
Delayed Type IV hypersensitivity reaction
What is the pathophysiology of contact irritant dermatitis?
Trauma eg. soap
What is the pathophysiology of atopoic dermatitis?
Genetic and environmental factors resulting in inflammation
What is the pathophysiology of drug-induced dermatitis?
Type I or IV hypersensitivity reaction
What is the pathophysiology of stasis dermatitis?
Physical trauma to skin - hydrostatic pressure
What is the pathophysiology of lichen simplex dermatitis?
Physical trauma to skin - scratching
What test can be done for contact allergic dermatitis?
Patch testing
What is the treatment for irritant contact dermatitis?
Topical steroids and emollients
Which areas are atopic eczema/dermatitis found?
Flexural
What is a critical symptom for atopic eczema/dermatitis?
Pruritus
Lichenification
Increased skin markings
What does golden crusting in atopic eczema indicate?
Staph. aureus infection
What causes eczema herpeticum and what does it look like?
Herpes simplex virus, looks like monomorphic punched-out lesions
What is the diagnostic criteria for atopic eczema/dermatitis?
- Visible or history of flexural rash; Personal history of atopy; generally dry skin; onset before 2yrs
What are the treatments of atopic eczema/dermatitis?
Emollients; topical steroids; antibiotics for infections; phototherapy (UVB); systemic immunosuppressants
Which gene is most associated with atopic eczema?
Filaggrin
What is the characteristic of discoid eczema?
Well defined, round lesions
Pruritus
A usually unpleasant, poorly localised, non-adapting sensation that provokes the desire to scratch
What are the mediators of itch?
Chemical mediators (eg. histamine, ACh, PGE2), nerve transmission (unmyelintated C fibres) and opiates in the CNS
What are the 4 main categories of causes of itch?
Pruritoceptive (trigger in the skin), neuropathic (damage of central/peripheral fibres), neurogenic (opiates on CNS fibres but no damage) and psychogenic
What are examples of anti-itch treatments?
Anti-histamines, emollients, antidepressants, phototherapy,
What is chronic venous insufficiency?
Occurs when the valves of the veins do not function correctly and venous drainage is impaired. The failure of the valves allows the blood to flow back down (reflux) into the section of vein below
How does chronic venous hypertension lead to leg ulcers?
Chronic venous hypertension causes abnormalities in the capillaries in the leg tissues that make them more permeable. This allows fluid, proteins and blood cells to leak into the tissues. They may also cause increased inflammatory response, changes in the structure of the microvasculature and reduced skin and tissue oxygenation. Overall, these effects contribute to greater skin fragility and increased risk of leg ulceration and delayed healing
What is the definition of a leg ulcer?
Any break in the skin of the lower leg above the ankle that is present more than 4 weeks
Which type of leg ulcers are most common?
Venous ulcers
Which ulcers look ‘punched out’ and deep, and often occur on the foot?
Arterial ulcers
Which ulcers appear superficial, have shallow edges and rarely involve the foot?
Venous ulcers
What are signs of venous disease that should be looked for?
Varicose veins; atrophie blanche; lipodermatosclerosis; haemosiberin
What is lipdermatiosclersis?
‘Champagne leg’, a type of panniculitis (inflammation of subcutaneous fat) which cause skin hardening, increased pigmentation, swelling and redness
What is a normal ABPI range?
0.8-1.3
What is the aim of compression treatment?
To heal ulcers within 12 weeks
What is Imiquimod?
An immune modulator which can be used as a cream to treat pre-cancers and BCC
Vitiligo
‘White spot disease’ - an autoimmune disease with loss of melanocytes due to autoimmune attack
Albinism
In this disorder there is a genetic partial loss of pigment production
Nelson’s Syndrome
Melanin stimulating hormone is produced in excess by the pituitary
What clinical conditions occurs when venous valves become weak and dilated?
Varicose veins
What conditions can lead to chronic insufficiency and consequently DVT or venous ulceration?
Poor circulation, stasis or immobility
What causes skin ulceration following chronic venous insufficiency?
Superficial microcirculatory deficiencies
- (Venous pressure increases
- Damages blood vessels in skin
- Skin becomes dry, itchy and inflamed
- Cannot heal well due to poor blood supply
- Begins to break down
What causes thrombosis/embolism following chronic venous insufficiency?
Deep venous stasis
Which classification is used to determine skin photo type?
Fitzpatrick skin prototypes (I to VI)
What causes photosensitivity?
An abnormal reaction to some component of the electromagnetic spectrum of sunlight and a chromophore (reactive compound) within the skin.
Photosensitivity
Various symptoms, diseases and conditions caused or aggravated by exposure to sunlight.
What is the underlying cause of Porphyria Cutanea Tarda?
PCT is due to a defective enzyme in the liver (uroporphyrinogen decarboxylase). This causes an increase in porphyrins in the skin result in photosensitivit
What is the typical presentation of PCT?
Blisters and fragility, particularly on the backs of hands
What investigations can be done for PCT?
Wood’s lamp (looking for excessive porphyrins) or skin biopsy
What is the underlying cause of Erythropoietic Protoporphyria (EPP)?
EPP is due to an inherited deficiency of the enzyme ferrochelatase. Reduced activity of this enzyme causes a build-up of the chemical protoporphyrin in the skin; resulting in photosensitivity
What is the most common type of porphyria?
Porphyria cutanea tarda
