Dermatology Flashcards
What are the different layers forming the skin?
- Stratum corneum
- Stratum lucidum
- Stratum granulosum
- Stratum spinosum
- Stratum basale
- Dermis
What cells give skin it’s pigmentation and which layer do they lay in?
-Melanocytes in the basal layer
When describing skin lesions how is it best to describe them?
- Distribution
- Configuration
- Morphology
What are some distribution factors of skin lesions to consider?
-Where on the body it is? >Flexures ie eczema >Extensors ie psoriasis >On the face ie seborrhoeic >Dermatomoal ie shingles >Intertriginous ie in moist areas such as under the breast -Pattern >Symmetrical ie vitilgo
What are some configuration factors of skin lesions?
- Linear
- Targetoid (3 concnetric rings ie erythema multiforme)
- Annular (ring shaped) ie tinea, ring worm, lupus
- Discoid ie discoid lupus
- Reticular ie livedo reticularis
- Clusters
How can the morphology of a skin lesion be described?
- Macular (flat)
- Papule (raised)
- Plaque (elevated, well circumscribed raised area) ie psoriasis
- Nodule (big papule)
- Vesicle (small blister - if >5mm = bulla)
- Crust (dry blood/serum)
- Scale (hyperkeratosis)
What is the most important diagnosis to consider with a skin lesion?
-Skin cancer
What are the Fitzpatrick skin types
I: never tans, always burns (red hair, freckles, blue eyes
II: usually tans, always burns
III: always tans, sometimes burns (dark hair, brown eyes)
IV: always tans, rarely burns (olive skin)
V: Sunburn and tan after extreme UV exposure (brown skin)
VI: Black skin, never tans, never burns
What is the most common type of skin cancer?
-Basal cell carcinoma
What are the risk factors for basal cell carcinoma?
- UV exposure in the elderly (long time exposure)
- Fair skin
- Immune suppression
- Genetic factors
What are the features of basal cell carcinomas?
- Shiny ‘pearly surface’
- Telangiectasia (branch line capilarries)
- Central nodule/’rodent ulcer’
- Surface ulceration
- Rolled edge
- Locally invasive (won’t met)
- Slow growing over 1+ year
How are superficial BCCs managed?
- Creams if stay superficial
- Excision by Moh’s micrographic surgery >for ill-defined and large BCC on risky sites
- Radiotherapy
What are risk factors/causes for malignant melanoma
- UV light exposure
- Fair skin (Fitzpatrick I or II)
- Red hair
- > 100 Naevi on body
- > 5 atypical naevi on body
- Family history
What are features of malignant melanoma?
- Asymmetry
- Border irregularity
- Colour irregularity
- Diameter >6mm
- Evolving
What is the most common type of melanoma?
-Superficial spreading
> others: nodular, lentigo maligna, melanoma of the nails
What is the most important prognostic indicator for malignant melanoma?
-Breslow thickness
> Thickness of the melanoma. thicker = worse prognosis
How is malignant melanoma treated?
- Excision
- Chemo, radio and immunlogical therapy for palliative pts with mets disease
Where do malignant melanomas commonly metastasis to?
- Lungs
- Brain
Which skin cancer is most likely to be keratotic and faster growing?
-Squamous cell carcinomas
What are risk factors/causes for squamous cell carcinomas?
- UV light exposure over long time frame
- Immune suppression
- Actinic keratoses and Bowen’s disease
- Smoking
- Long standing leg ulcers
- Genetic conditions ie albinism, xeroderma pigmentosum
What are features of squamous cell carcinoma?
- Potential to metastasise
- High risk sites: lips and ears
- Keratotic appearance
How are SSCs treated?
- Surgical excision
- Moh’s micrographic surgery for high risk pts/cosmetic areas
What are 3 types of ulcers seen on skin?
- Venous
- Arterial
- Neuropathic
What are features of venous ulcers?
- Commonly over the medial malleolus
- May have varicose veins
- Haemosiderin patches/deposits in the skin
- Lipodermatosclerosis
- Venous eczema (dry/shiny)
How are venous ulcers managed?
- Compression bandages as 1st line
- Refer to vascular surgery if not effective
What is the most important investigation to perform for skin ulcers?
-ABPI
>Normal: 0.9-1.2
»Compression bandages should not be used if <0.9 as could lead to criticla limb ischaemia
What are features of arterial ulcers?
- Peripherally located at distal points, pressure sites
- Deep, punched out and necrotic
- Painful
- Shiny skin
- Increased cap refill time
- Absent pedal pulses
- Hypoperfusion signs ie lack of hair
- Risk factors for ateial disease
- Abnormal ABPI
How are arterial ulcers managed?
- Referral to vascular surgeons
- Exercise
- Modify CV Risk factors
What are the features of neuropathic ulcers?
- Most commonly seen in diabetes
- Commonly over plantar surface of the metatarsal head and hallux
- Occur on pressure sites
- Punched out/necrotic
- Caused by sensory impairment to the area
How are neuropathic ulcers treated?
- Education of diabetic foot health
- Cushioned shoes and appropriate dressings to relieve pressure and reduce callous formation
What is the most common form of eczema/dermatitis?
-Atopic eczema
What are some triggers/causes of eczema?
- Dry skin
- Hot/cold temperatures
- Irritants
- Allergy
What are features of eczema?
- Patches of dry red itchy skin
- Adults/older children: flexor surfaces
- Babies: face and trunk
- Contact dermatitis: in distribution to exposure
How is eczema managed?
- Emollients daily
- Topical steroids for acute flares: when not responding to treatment
- Steroid sparing agents
What are some examples of steroid sparing agents?
- Topical calcineuin inhibitors: tacrolimus
- Antihistamines (fotr itch)
- 2nd line systemic treatments: azathioprine, MTX
What life threatening emergency caused by herpes simplex virus 1 or 2?
- Eczema herpeticum
- Usually occurs in children with pre-existing eczema
What is the management for eczema herpeticum?
- Admit to hospital
- IV acyclovir
What is psoriasis?
- Chronic skin condition which squaly plaques form on the extensor surfaces of the body
- Can affect scalp and nails
What are the different types of psoriasis?
- Chronic plaque psoriasis
- Flexure psoriasis
- Scalp
- Guttate
- Palmar-plantar
- Nail
- Generalised pustular
What are the features of nail psoriasis?
- Pitting
- Oncholysis
- Thick/hyperkeratotic nails
What are some possible triggers of psoriasis?
- Stress
- Alcohol
- Smoking
- Trauma
- Steroid withdrawal
Which medications trigger psoriasis?
- Beta blockers
- Lithium
- NSAIDs
- ACEi
- TNF inhibitors
- Anti-malarials
What is Koebner phenomenon?
-Psoriasis that spreads to an area of skin that has been broken
ie will move down the track line a scratch
How is psoriasis managed?
- Emollients
- Topical steroids and vit D analogues ie Dovobet
- Vit D analogues
- UV light therapy
- Traditional systemic therapies ie retinoids, MTX, ciclosporin
- Biologics ie anti-TNF (infliximab, adalamumab)
What other factors need to be considered/looked for with someone who has psoriasis?
- Psoriatic arthritis
- Adults with psoriasis are at increased risk of CV disease
What triggers guttate psoriasis and what is it?
- Triggered by strep throat (strep group A)
- Raindrop shaped plaques
- Silver scale
- Trunk
How is guttate psoriasis investigated and treated?
-Throat swab for anti-streptolysin O titre
-RX:
>Most self resolve within 2-3 months
>Topical agents as per psoriasis
>UVB phototherapy
What is acne vulgaris?
-Common skin condition affecting adolescents usually affecting the face, neck and trunk
What’s the pathology behind acne?
-Obstruction of the pilosebacious follicles with keratin plugs causing:
>Comedones
>Inflammation
>Pustules
What is the causative organism responsible for acne vulgaris?
-Propionibacterium acnes
What are the features of acne vulgaris?
- Comedones: dilated sebaceous follicles (closed top: white heads, open top: blackheads)
- Papules
- Pustules
- Nodules
- Cysts
- Scarring
How is acne vulgaris managed?
- Single topical therapy ie topical retinoids or benzylperoxide
- Topical combination ie tetracycline and a stage 1 topical therapy
- Oral antibiotics (oxytetracycline or doxycyline) may need to wait 3-4 months
- Oral isotretinoin
What are some side effects of isotretinoin?
- Dry skin
- Depression
- Liver function derangement
- Increase in serum triglyceride
- Teratogenic
- Hair thinning
- Nose bleeds
- IIH
- Photosensitivity
What is Wallace’s rule of 9s for burns?
- Arm 9%
- Front of leg 9%
- Back of leg 9%
- Front of torso 9%
- Back of torso 9%
- Front of abdomen 9%
- Back of abdomen 9%
- Head and neck 9%
What are different gradings for burns?
- Superficial epidermal: red, painful
- Superficial dermal: red, painful, blistered
- Deep dermal: decreased sensation, white
- Full thickness: white, no pain, no blisters, muscle and bone involvement
What is the Parkland formula for burns?
-Calculates how much fluid replacement someone needs following a burn
What is the calculation for the Parkland formula?
- Fluid requirement (mls) = TSBA burn (%) x body weight (kg) x 4
- over 24 hours
What is the management of burns?
- ABCDE
- Stop the burning
- Clingfilm
- Monitor U&Es
- Superficial burns: use emollients
- If circumferential: escharotomy
- Analgesia
- Non-adherent dressing
What are the indications for referral to secondary care
- Any burn affecting the face, neck, hands, feet and genitals
- Any deep dermal or full thickness burns
- Smoke inhalation injury
- Chemical or electrical burns
- NAI
What are the features of acne roasacea?
- Affects the nose, cheeks and forehead
- Flushing (can be alcohol related)
- Telangiectasia
- Later: develops into persistent erythema with papules and pustules
- Rhinophyma
- Blepharitis, keratitis, conjunctivitis
How is acne rosacea managed?
- topical metronidazole
- Systemic antibiotics: oxytetracycline
- high SPF suncream
- Camouflage creams to conceal redness
- Laser treatment for telangectasia
- surgical repair of rhinophyma
What is bullous phemigoid?
- An autoimmune condition causing sub-epidermal blistering of the skin
- Causes itchy tense blisters around the flexures
Who is commonly affected by bullous phemigoid?
-Elderly patients
What does a biopsy of bullous phemigoid contain?
-IgG and C3
How is bullous phemigoid managed?
- Refer to dermatology
- Oral corticosteroids
What is vitilgo?
- An autoimmune disease causing a loss of melanocytes = depigmentation
- Commonly presents in 20s-30s
Management of vitiligo?
- Sunscreen for affected areas
- Camouflage make up
- Topical corticosteroids
- ?Tacrolimus and phototherapy
What diseases are associated with vitiligo?
- T1DM
- Addison’s disease
- Pernicious anaemia
- Autoimmune thyroid disease
- Alopecia areata
What is alopecial areata?
- An autoimmune cause of localised hair loss
- Occurs in well demarcated patches
Management of alopecia areata?
- Usually regrows back itself
- Education
- Topical steroids
- Topical minoxidil (restores blood supply to area)
- Phototherapy
- Contact immunotherapy
- Wigs
What is erythema nodosum?
-Inflammation of the subcutaneous fat
What are the features of erythema nodosum?
- Tender
- Erythematous
- Nodular lesions
- Usually over the shins
What are the causes of erythema nodosum?
- Infection ie TB, strep
- Systemic disease ie IBD, sarcoidosis, Bechets
- Malignancy ie lymphoma
- Pregnancy
- Drugs ie penicillin, cocp, sulphonamides
How is erythema nodosum managed?
- Usually self resolves within 6 weeks
- Lesions heal without scarring
- Treat pain with analgesia
What is pellagra?
- A disease caused by deficiency of nicotinic acid (Vit B3)
- Common in alcoholics
- Can occur as consequence of isoniazid therapy
What are the features of pellagra?
-4 Ds >Diarrhoea >Dementia/depression >Dermatitis - brown and scaly skin on sun exposed areas >Death (if not treated)
How is pellagra managed?
-Vitamin B3 supplementation
What is keratocanthoma?
-Benign epithelial tumour filled with keratin
>looks like a volcano/crater
>SCC needs to be excluded
How are keratocanthomas managed?
-Usually regress within 3 months. (often scars)
-Should be excised
>5% progress to SCC
What is seborrhoeic dermatitis?
-Chronic inflammation reaction to a normal skin inhabitant - Malassezia furfur
What are some associations with seborrhoeic dermatitis?
- HIV
- Parkinson’s disease
Which parts of the body does seborrhoeic dermatitis affect?
- Scalp
- Periorbital
- Auricular
- Nasolabial folds
- Cheeks
How is face and body seborrhoeic dermatitis managed?
- Topical antifungals ie ketoconazole
- Topical steroids (for short term use for acute flares)
How is scalp seborrhoeic dermatitis treated?
- Head and shoulders shampoo (contains zinc pyrithione)
- 2nd line: ketoconazole
- Selenium as topical steroid
What are seborrhoiec keratoses?
-Seborrhoeic warts
>benign, epidermal lesions
-Commonly affects older people
What are the features of seborrhoiec keratosis?
- Vary in colour: pink fleshy, light brown, dark brown, black
- ‘Stuck on’ appearance
- Keratotic plugs on surface
Management of seborrhoeic keratoses?
- Reassure as benign
- Removal if irritating: curettage, cryosurgery
What is actinic keratosis?
-Premalignant condition associated with chronic skin exposure
What is the spectrum of disease associated with actinic keratosis?
- Photodamage
- Actinic keratosis
- SCC in situ (Bowen’s disease)
- Invasive SCC
What are the features of actinic keratosis?
- Small crusty lesions
- Pink, red, brown or skin colour
- Typically on skin exposed areas
- Multiple lesions can be present
How are actinic keratoses managed?
- Reduce further risk with sun avoidance/sunscreen
- Flurouracil cream
- Topical diclofenac
- Cyrotherapy
- Curretage and cautery
What is erythema abigne?
-Rash caused by heat exposure
ie old lady using hot water bottle to treat back pain for hours
-Risk factor for SSC
-Needs to treat the reason why they are using the heat ie the back pain
What is acanthosis nigricans?
-Brown/black poorly defined velvety hyperpigmentation
-Found in the body folds
>neck
>axilla
>groin
>umbilicus
>forehead
What conditions are associated with acanthosis nigricans?
-Insulin resistance
-Paraneoplastic
>pancreatic and gastric malignancies
>involvement of mucous membranes suggests malignancy
What are the features of pyoderma gangrenosum?
- A lesion which initially starts as a small red papule and later develops into a deep red necrotic ulcer with a purple border
- Typically affects lower limbs
What causes pyoderma gangrenosum?
- 50% idiopathic
- IBD
- Connective tissue disorders: RA, SLE
- Myeloproliferative disorders
- Lymphoma, myeloid leukaemia
- Monoclonal gammopathy
- Primary billiary cirrhosis
How is pyoderma gangrenosum treated?
- Oral steroids
- If not responsive: ciclosporin, infliximab
What are features of lichen sclerosus?
- An inflammatory condition affecting the vulva
- White plaques caused by atrophy of the epidermis and itch
- Biopsy is diagnostic
How is lichen sclerosus managed?
- Topical steroids
- Emollients
- Careful follow up due it increased risk of vulval cancer
What are the features of lichen planus?
-All the Ps:
>Purple
>Pruritic
>Papular
>Polygonal
-Most common on palms, soles and genitals
-White lace pattern on the surface ‘Wickham’s striae’
-Nail signs: thinning of nail plate, longitudinal ridging
What are some causes of lichenoid drug eruptions?
- Gold
- Quinine
- Thiazides
How is lichen planus managed?
- Topical steroids
- Oral disease: benzylamine mouthwash
- Oral steroids/Immune suppression for extensive disease
What is molluscum contagiosum?
-Raised papules caused by molluscum contagiosum virus
What is molluscum transmitted?
- Close personal contact
- Contaminated surfaces such as shared towels and flannels
What are features of molluscum?
- Pinkish/pearly white papules
- Central umbilication
- Up to 5mm diameter
- Lesions appear in clusters
- Spares palms and soles
- Children: trunk and flexures
- Adults: sexual contact can lead to lesions on the genitalia, pubis, thighs, lower abdomen
Self care advice for molluscum?
- Advise patients this is a self limiting condition, lasts <18 months
- Contagious towel sharing
- Don’t scratch
What are treatment options for molluscum?
- Squeeze after a bath
- Cyrotherapy
- Steroids if itchy
- Antibiotics if crusted/infective looking
When should someone with molluscum be referred for specialist input?
- HIV positive
- Eyelid/ocular margin lesions
- Anogenital lesions: refer to GUM
What is scabies?
- A sarcopetes scabeii bite
- Commonly affects children and young adults (shared houses)
- Eggs laid in stratum corneum
What are the features of scabies?
- Widespread pruritus
- Linear burrows (side of fingers, web spaces, flex of wrist
- Excoriations
- Infants: face and scalp
- Complicated in immunosuppressed: crusted scabies
How long will the pruritus from scabies persist for following successful treatment?
-4-6 weeks
How is scabies treated?
- Permethrin 5%
- Ensure whole household treated
- Clean all clothes, bedding, towels etc on 1st day of treatment
WHat is hyperhidrosis?
-Excesive sweating
How is hyperhidrosis managed?
- Topical aluminium chloride
- Electric current: iontophoresis
- Botox of axilla
- Surgery
What is hereditary haemorrhagic telengectasia?
-An autosomal dominant condition characterised by multiple telangiectasia over the skin and mucus membranes
What are the diagnostic criteria for hereditary haemorrhagic telengiectasia?
- Epistaxis: Spon. nose bleeds for >3/7
- Telangiectasia: Multiple at lips, oral cavity, fingers, nose
- Visceral lesions: Gi telangiectasia (on colonscopy), Atriovenous malformations - pulmonary, hepatic, cerebral, spinal
- Family history
What are the features of pityriasis rosea?
- Acute self-limiting rash (resolves after 4-12 weeks)
- Young adults
- Associated with HHV-7
- Herald patch (early lesion) - appears on trunk
- Followed by erythematous oval scaly patches
- URTI prodrome
What skin condition is a medical emergency?
-Erythroderma!
>when >95% of skin is involved in a rash of any kind
What are some causes of erythroderma?
- Idiopathic
- Eczema
- Psoriasis
- Lymphoma
- Leukaemia
- Drugs: Gold
What are features of erythroderma?
- Dry mucous membranes
- Pain/discomfort
- Hypothermia
- Electrolyte imbalances
What parameters need monitoring for a pt with erythroderma?
- Dehydration
- Infection
- High output cardiac failure (SOB)
- Hypothermia
How is erythromderma managed?
- Admit to hospital urgently
- IV fluids
- Analgesia
- Emollients
- Cool wet dressings
- Bed rest in warm room
- Nutritional support
