Dermatology Flashcards
What is pemphigus vulgaris?
Autoimmune condition characterised by IgG antibodies against desmoglein 3
When does pemphigus vulgaris normally occur?
Middle age
What are risk factors for pemphigus vulgaris?
Jewish descent, drugs (NSAIDs, ACEis)
How does pemphigus vulgaris present?
Flaccid blisters that are easily ruptured to form shallow erosions. Not itchy. Seen in face, scalp, axilla, mucosa
Is pemphigus vulgaris Nikolsky sign +ve or -ve?
Positive
What does immunofluorescence of Pemphigus Vulgaris show?
Intracellular IgG deposits
‘Crazy paving/chicken wire appearance on immunofluorescence’
Pemphigus vulgaris
What is the treatment of pemphigus vulgaris?
Topical steroids and pain relief
Prednisolone +/- azaithioprine, dapsone, ciclosporin
What is the prognosis of pemphigus vulgaris?
Remits in 3-6 years, mortality rate of 10-20%
What is bullous pemphigoid?
Autoimmune condition characterised by antibodies against the BM
What age group commonly get bullous pemphigoid?
Elderly
How does bullous pemphigoid present?
Itchy tense bullae, around flexures, on an urticarial base. Usually without scarring, mouth spared
Is bullous pemphigoid Nikolsky sign +ve or -ve?
Negative
What is seen on immunofluorescence in bullous pemphigoid?
IgG and c3 deposits at dermoepidermal junction
How is bullous pemphigoid managed?
Topical steroids
Oral prednisolone, tetracyclines, azaithioprine, dapsone
What is the prognosis of bullous pemphigoid?
Chronic self limiting course, most achieve remission in 3-6 months
What is dermatitis herpetiformis?
Autoimmune blistering skin condition caused by IgA deposition in the dermis
What is dermatitis herpetiformis associated with?
Coeliac disease
How does dermatitis herpetiformis present?
Itchy, vesicular skin lesions on extensor surfaces, buttocks, face and scalp. On erythematous bases
What is seen on histology in dermatitis herpetiformis?
Papillary dermal microabscesses
IgA deposits in dermal papillae
How is dermatitis herpetiformis treated?
Gluten free diet
Dapsone, tetracyclines
What is acne vulgaris?
Common chronic inflammatory condition of the pilosebaceous unit
What percentage of teenagers does acne vulgaris affect?
80-90%
What are the 4 main pathogenesis’ of acne vulgaris?
Duct occlusion
Increased sebum production
Bacterial colonisation
Inflammation
What bacteria commonly colonise in acne vulgaris?
P. Acnes, staph epidermidis
What are aggravating factors for acne vulgaris?
Diet, premenstrual, sweating, UV radiation, job (Steam/oil), stress
What atrophic scarring is seen in acne vulgaris?
‘Ice pick lesions’
What hypertrophic scarring is seen in acne vulgaris?
Keloid
What is mild acne?
Scattered papules and pustules
What is moderate acne?
Numerous papules, pustules, atrophic scarring
What is severe acne?
Papules, pustules, nodules, significant scarring
What is the first line management of acne?
Single topical treatment
What topical treatments are there?
Topical antibiotics
Topical retinoids
Benzoyl Peroxide
What is second line management of acne?
Combined topical treatment
What is 3rd line management of acne?
Oral antibiotics or OCP
What oral antibiotics are used for management of acne vulgaris?
Erythromycin, oxytetracycle, lymecycline, doxycycline
What are side effects of oral antibiotics?
Gi upset, thrush, photosensivity
What type of COCP is used for acne vulgaris?
Dianette, triphasic pills
How will progesterone only contraception affect acne vulgaris?
May exacerbate it
What is 4th line acne treatment?
Oral retinoids
How doe oral isotretinoin (roaccutane) work?
Reduces sebaceous gland activity
What are side effects of roaccutane?
Dry skin, lips, eyes, skin fragility, hyperlipidaemia, abnormal LFTs, teratogenic, mood alteration, hair thinning,
What is acne rosacea?
Chronic skin condition of unknown aetiology
How does acne rosacea present?
papules, pustules and erythema, prominent facial flushing (worsened by spicy food/alcohol)
What is acne rosacea associated with?
Blepharitis
How is acne rosacea managed?
Avoid dietary triggers
Topical metronidazole
Telangactasia - laser therapy
Rhinophyma - surgery/laser shaving
What is eczema?
Inflammatory skin condition often starting in early infancy
What are causes of eczema?
Multifactorial - genetics, allergens, diet, overwashing, poor barrier, filaggrin deficiency, dryness, heat, cold, stress, infection
Which social class is there a higher incidence of eczema in?
Higher social classes
How does eczema present?
Itchy, red, flexural rash. Chronic scratching causes lichenification, scarring, infection
How is eczema diagnosed?
Itching PLUS 3 OF
visible flexural rash, history of flexural rash, personal/family history of atopy, dry skin, onset before 2
What is step 1 in eczema management?
Emollients
What is step 2 in eczema management?
Emollients + mild steroid
What is step 3 in eczema management?
Emollients + mild steroid + calcineurin inhibitor
What is step 4 in eczema management?
Emollients + potent/very potent steroid
How should emollients be used?
Liberally (500g/week), also bath and shower emollients
What are the effects of topical steroids?
Anti-inflammatory
Vasoconstrictive
Antiproliferative
What are side effects of topical steroids?
Skin thinning, increased infections, telangastasia, cushings
How much steroid does one finger tip unit cover?
Two hands
What is an example of a mild topical steroid?
Hydrocortisone
What is an example of a moderate topical steroid?
Eumovate
What is an example of a potent topical steroid?
Betnovate
What is an example of a very potent topical steroid?
Dermovate
What are examples of calcineurin inhibitors?
Tacrolimus, pimecromilus
What can be used if eczema is severe and does not respond to topical treatments?
Phototherapy, systemic agents (e.g. azaithioprine, methotrexate, mycopentolate)
What organism is the cause of infected eczema?
Staph Aureus
How is infected eczema treated?
Fusidic acid
What is eczema herpeticum?
Herpes simplex infection of eczema
How does eczema herpeticum present and how is it treated?
Monomorphic rash with circular blisters
EMERGENCY - admit for IV aciclovir
What is psoriasis?
Chronic relapsing remitting condition
When is the peak incidence of psoriasis?
20s-50s
What is the underlying pathophysiology of psoriasis?
Hyperproliferation of epidermal cells
What is the normal skin turnover?
25 days ish
What is the skin turnover in psoriasis?
5 days
What does histology show in psoriasis?
Parakeratotic statum corneum
Absence of granular layer
Extended prickle cell layer
How does chronic plaque psoriasis present?
Erythematous, scaly plaques on extensor aspects of skin. Palpable and shiny with silvery scale. Koebner phenomenon
What is the Koebner phenomenon?
Skin lesions arising in areas of trauma
How does guttate psoriasis present?
Usually occurs 2-4 weeks post strep infection. ‘Tear drop’ scaly patches. Resolves spontaneously in 2-4 months
How does flexural psoriasis present?
Shiny red well demarcated plaques in flexural surfaces
How does erythrodermic psoriasis present?
90% of skin surface goes red. Usually occurs in patients with psoriasis and is due to UV burns/withdrawal of steroids
What nail changes may be seen in psoriasis?
Pitting, onycholysis, oil drop lesions, sublingual hyperkeratosis, deformity
How is psoriasis managed 1st line?
Topical treatment
What topical treatments are available for psoriasis?
Emollients, tar, vitamin D analogues, salicylic acid, dithranol, steroids
How does coal tar work?
Reduces DNA synthesis and epidermal proliferation
What is an example of a vitamin D analogue?
Calcitriol
What does salicyic acid do in psoriasis?
Removes hyperkeratosis
How does dithranol cream work?
Anti-mitotic - used in short regimes as can burn skin
What is second line treatment for psoriasis after topical agents?
Phototherapy
What are the options of phototherapy?
UVB treatment or PUVA (psoralen topical.oral and UVA)
What is the 3rd line treatment for psoriasis after phototherapy?
Systemic treatment
What systemic treatments are available for psoriasis?
Methotrexate, ciclosporin, retinoids, biologics
What are causes of venous ulcers?
Venous hypertension secondary to venous insufficiency
What is the pathogenesis of venous ulcers?
Ulcers form due to capillary fibrin cuff or leucocyte sequestration
What are features of venous insufficiency?
Oedema, brown pigmentation, lipatodermatosclerosis, eczema
What are features of venous ulcers?
Superficial, above ankle (Gaiter area), painless
What investigations should be done for venous ulcers?
Doppler USS
ABPI
How are venous ulcers managed?
4 layer compression bandaging
What should the pressure of a bandage be for venous ulcer at the ankle?
Around 40mmHg
What should the pressure of a bandage be fore venous ulcers at the knee?
Around 25mmHg
How long should you aim to heal a venous ulcer in?
12 weeks
What should the ABPI be to be suitable for compression bandaging?
Over 0.8
What are causes of arterial ulcers?
Hypertension, atherosclerosis
What are the features of arterial insufficiency?
Hairless, pale, cold, unable to palpate pulses
What are features of arterial ulcers?
Deep, punched out, may see tendon, over heels/toes, painful
What investigations are done for an arterial ulcer?
Doppler USS
ABPI
What is the management of an arterial ulcer?
Pain relief, lifestyle changes, aspirin, treat infections, Soffban + crepe bandages to reduce oedema. Vascular surgery if needed
What does ABPI measure?
Ratio of systolic blood in the lower leg compared to the arms
What does a decreased pressure in the legs indicate?
Peripheral arterial disease
What is a normal ABPI?
1-1.2
What does an ABPI of 0.8-0.9 indicate?
Mild peripheral arterial disease
What does an ABPI of 0.5-0.79 indicate?
Moderate PAD
What does an ABPI less than 0.5 indicate?
Severe PAD
What does an ABPI above 1.2 indicated?
Calcification of artery
What is a Marjolins ulcer?
SCC occuring at a site of chronic inflammation
Who and where do neuropathic ulcers occur?
In diabetics. commonly on points on pressure (e.g. metatarsal head)
What is pyoderma gangrenosum?
Erythematous nodules than can ulcerate, associated with IBD, RA. may occur at stoma sites
What are symptoms of venous eczema?
Red, scaly rash that is intensely itchy. Often misdiagnosed as cellulitis
What are the causative organisms of impetigo?
Staph aureus, strep pyogenes
How does impetigo present?
Well defined lesions with a honey coloured crust and erythematous base
How is impetigo treated?
Topical fusidic acid
If sevre - oral flucloxicillin
What are complications of impetigo?
Bullous impetigo
Staphylococcal scolded skin syndrome
What is staphylococcal scaled skin syndrome?
Loss of epidermis secondary to exotoxin release
What is folliculitis?
Superficial infection of hair follicle
What is a boil?
Deep infection of a single hair follicle
What is a carbuncle?
Deep infection of multiple hair follicles
How does folliculitis/boils/carbuncles present?
Discrete erythematous papules/pustules on hair bearing sites, itch
How are boils and carbuncles treated?
Oral flucloxacillin
What is cellulitis?
Acute infection of skin and soft tissues
What are causes of cellulitis?
Strep pyogenes, staph aureus
How does cellulitis present?
Usually in legs, macular hot erythema with ill defined margins that is often spreading. Associated fever, malaise, leg pain, swelling, local lymphadenopathy
How is cellulitis managed?
Flucloxacillin orally
If a patient gets recurrent cellulitis, what should you consider swabbing for?
Panton-Valentine-Leucocidin
What is erysipelas?
Superficial form of cellulitis
What is erysipelas caused by?
Strep Pyogenes
How does erysipelas present?
Spreading rash, commonly on face. Well demarcated, erythematous plaque, systemic upset
How is erysipelas treated?
IV flucloxacillin
What is necrotising fasciitis?
Infection of soft tissue and fascia
What causes type 1 necrotising fasciitis?
Mixed aerobe/anaerobe
What causes type 2 necrotising fasciitis?
Strep pyogenes
What causes type 3 necrotising fasciitis?
Clostridia
How does necrotising fasciitis present?
Acute onset, painful, erythematous lesions, extremely tender over tissue
How is necrotising fasciitis managed?
Surgical debridement, IV antibiotics
What causes skin warts?
HPV types 1-4
How do warts present?
Raised papules with firm, rough surface, cauliflower appearance
How are warts managed?
Salicylic acid, cryotherapy, imiquimod
What causes molluscum contagiosum?
Pox virus
How does molluscum contagiosum present?
Itchy, solid, pearly pink papules with umbilicated centre
How is molluscum contagiosum managed?
Self limiting
What causes coldsores?
Herpes Simplex Virus 1
How does herpes simplex virus (coldsores) present?
Single or grouped painful itchy vesicles on erythematous base that burst without scarring
What is herpetic whitlow?
HSV lesion on finger
How is HSV managed?
Analgesia
Topical/oral aciclovir
What causes chicken pox?
Varicella Zoster virus
How does chicken pox present?
Macules -> papules -> vesicles that crust over and recover. Intensely itchy
What is the cause of shingles?
Herpes Zoster - reactivation of VZV in dorsal root ganglion
How does shingles present?
Erythematous macules, burning and tingling pain, dermatomal distribution
How is shingles managed?
Oral aciclovir + analgesia
How does a dermatophyte infection present?
Erythematous, scaly itchy ring shaped lesion with expanding edge and resolving centre. Named by body site.
How is a dermatophyte infection treated?
Topical/oral antifungals
What causes thrush?
Candida albicans
How does thrush present?
Itchy scale, ragged peeling edges. In mouth - white lesion that can be scraped off.
How is thrush treated?
Oral = miconazole Skin = topical clotrimazole or oral antifungal
What causes pityriasis vesicular?
Melassezia yeast
How does pityriasis vesicular present?
Well defined macular lesions with fine scale that are hypo or hyperpigmented. Often noticed after being on holiday
How is pityriasis vesicular treated?
Topical ketoconazole
What is the most common skin cancer?
BCC
What are risk factors for BCC?
Fair skin, UV exposure, intermittant sun damage
How does a nodular BCC present?
Raised lesion with pearly shiny papule, rolled edge, central ulceration, telangactasia
‘Rodent ulcer’
BCC
How is BCC diagnosed?
Clinical suspicion and biopsy
How is BCC managed?
Leave and monitor
Topical imiquimod
Cryotherapy
Surgery/MOHS
What is actinic keratosis?
Premalignant lesion, develops as a consequence of sun exposure
How does an actinic keratosis present?
Small crusty or scaly lesion. May be pink/brown/red/same colour as skin. Typically on sun exposed sites
How is actinic keratosis’ managed?
Prevention of further risk Fluorauricil cream Topical diclofenac Topical imiquimod Cryotherapy/Currettage/Cautery
What is Bowens disease?
Intraepidermal SCC
How does Bowens disease present?
Slow growing red scaly plaque, typically on shin
How is Bowens disease managed?
Topical fluoracil
Topical Imiquimod
Cryotherapy
Excision
What is the commonest skin cancer post transplant?
SCC
What are risk factors for SCC?
Excessive sunlight exposure, PUVA, actinic keratosis, Bowens disease, immunosuppression, smoking, long standing ulcers
How does an SCC present?
Grows slowly over months, firm erythematous plaque over sun exposed site. Associated scale, crust bleeding, tenderness, itch
How is SCC managed?
Surgical excision
What is a malignant melanoma?
Tumour derived from melanocytes
What are risk factors for malignant melanoma?
Personal/family history, large number of moles, excess sun exposure, sunbed use, immunosuppression
What are the two growth phases of melanomas?
Radial and vertical
What is the radial growth phase of a melanoma?
Grows horizontally within the epidermis
What is the vertical growth phase of a melanoma?
Lesion becomes elevated and invades dermis
What is the commonest type of melanoma?
Superficial spreading
How does superficial spreading melanoma present?
Growing, changing mole
How does a nodular melanoma present?
Red/black lump that oozes and bleeds
Who do lentigo malignas occur in?
Elderly sun exposed skin
What is an acral lenitgo?
A melanoma arising on the palms, nails or soles of feet
How is assessment of a melanoma done?
Asymmetry, Border, Colour, Diameter >6mm, evolving
How is a melanoma managed?
Surgical excision with 2mm margins +/- sentinel node biopsy
If advanced can do chemo/radio/immunotherapy
What is a prognostic indicator in melanoma?
Breslow thickness
What is breslow thickness?
Measure of tumour thickness/depth, measured from basal layer of epidermis
‘Herald patch’
Pityriasis rosea
How is scabies treated?
Malathion lotion/permethrin cream
What is the cause of sebhorroeic dermatitis?
Malassezia
‘Hypersensitity reaction triggered by infections’
Erythema multiforme
What is ertythema ab igne caused by?
Infra-red exposure
‘Itchy white spots on vulva of elderly woman’
Lichen scleorsis
‘Pruritic purple pustular rash on flexors. Itchy’
Lichen planus
‘Wickhams striae’
Lichen planus
How is lichen planus treated?
Topical steroids
How is erythrasma treated?
Erythromycin
‘Exclamation mark hairs’
Alopecia areata
What drugs can commonly trigger psoriasis?
Betablockers and lithium
Lupus pernio
Sarcoidosis