Dermatology AS Flashcards
What is the epidemiology of Malignant Melanoma?
F>M = 1.5:1
UK incidence = 10,000/yr and 2000 deaths a year. Increased 80% in 20yrs.
What are the features of malignant melanoma?
Asymmetry Border: irregular Colour: non-uniform Diameter >6mm Evolving/Elevation
Risk factors for malignant melanoma?
- Sunlight: esp intense exposure in early years.
- Fair skinned (Low Fitzpatrick Skin Type)
- Increased no. of common moles
- +ve FH
- Increased age
- Immunosuppression
What is the classification of malignant melanoma?
Superficial spreading Lentigo maligna melanoma Acral lentiginous - most common in people with darker skin. On the palm Nodular Melanoma Amelanotic
What is superficial spreading malignant melanoma?
- 70% of cases
- Irregular border, colour variation
- Commonest in Caucasian
- Grow slowly, mets late = better prognosis
- Common on legs in females. Grows slowly, often taking months or years to be recognised.
What is Lentigo Maligna malignant melanoma?
Melanoma in situ - slowly but may at some stage become invasive causing lentigo maligna melanoma.
Suspicious freckles on face or scalp of chronically sun-exposed patients. Location is face!
- Often elderly patients
- Face of scalp.
- A growing mole
What is the acral lentiginous malignant melanoma?
- Rare form
- Asian/blacks
- Palms, soles, subungual (with Hutchinson’s sign) (black line )
- Can arise in the nail unit.
- Enlarging discoloured skin patch on the palms.
What is nodular malignant melanoma?
- All sites
- Second most common.
- Younger age, new lesions
- Invade deeply and mets early = worst prognosis.
- Presents with a red or black lump or lump which bleeds or oozes.
Tends to affect people over age of 50, with fairer skin, and occur in chronically sun exposed area.
Melanocytic naevi are risk factors
Congenital = typically appear at or soon after birth.
- Usually greater than 1cm
- Increased risk of malignant transformation
Junctional = melanocytic naevi = circular macules, may have heterogenous colour even within same lesion.
- Most naevi of the palms, soles.
Compound naevi = domed pigmented nodule up to 1cm in diameter
- Arise from junctional naevi .
Spitz naevi
= Children, red or pink in colour. Grow up to 1cm and growth can be rapid this usually results in excision.
What is amelanotic melanoma?
Atypical appearance –> delayed diagnosis.
What is the staging and prognosis of malignant melanoma?
Breslow Depth
- Thickness of tumour to deepest point of dermal invasion
- <1mm = 95-100% 5yrs
- > 4mm = 50% 5yr survival.
Where do the mets go in malignant melanoma?
Liver
Eye
What is the management of Malignant melanoma?
- Excision + secondary margin excision depending on Bres Depth.
± lymphadenopathy
± adjuvant chem
What are the margins of excision related to breslow thickness?
Lesions 0-1mm thick = 1cm
1-2mm thick = 1-2 cms
2-4mm = 2-3 cm
>4 = 3cm
What are the poor prognostic indicators of malignant melanoma?
- Male sex
- Increased mitoses
- Satellite lesions
- Ulceration
What is a squamous cell carcinoma?
- Ulcerated lesions with hard, raised EVERTED edges
- Telangiectasia scattered around periphery.
- Sun exposed areas
Causes of squamous cell carcinoma?
Sun exposure: scalp, face, ears, lower leg
Arise due to immunosuppression eg HIV, renal transplant. this is because of the immunosuppressants (higher risk of SCC).
May arise in chronic ulcer: Marjolin’s Ulcer (long standing leg ulcer) due to chronic inflammation.
Xeroderma pigmentosa
Development from actinic keratoses and Bowen’s disease (isolated and well demarcated)
Actinic keratoses - sun-exposed area. = Crusty, small, scaly lesions. Sun-exposed areas and multiple lesions may be present.
May be pink, red, brown or same colour as the skin. Typically on sun-exposed areas. Multiple lesions may be present.
What are good prognostic factors for SCC?
Well differentiated tumours
<20mm diameter
<2mm deep
No associated disease
What are poor prognostic factors?
Poorly differentiated tumours
>20mm in diameter
>4mm deep
Immunosuppression for whatever reason.
What is the progression of SCC?
Solar/actinic keratosis –> Bowen’s –> SCC
Lymph node spread is rare.
What is the management of SCC?
Surgical excision:
- 4mm margin if lesions <20mm in diameters.
- 6mm margin if lesion >20mm.
Management of actinic keratoses
- Sun avoidance, sun cream.
- Fluorouracil cream - 2/3 week course. Red and inflamed skin
- Topical diclofenac used for mild AKs.
- topical imiquimod
- Cryotherapy
- Curettage and cautery.
What is actinic ketatoses?
Red, scaly lesion on his forehead. Initially small and flat but not erythematous and rough to touch.
Irregular, crust warty lesion
premalignant (1%/yr)
- In a person with 7 actinic keratosis, risk of subsequent SCC is 10% at 10 yrs.
Management of AK?
Avoid sun, sun cream
- Fluorouracil cream: 2-3 week course. Skin will become red and inflamed.
- Topical diclofenac
- Topical imiquimod
- Cryotherapy
- Curettage and cautery
What is Bowen’s Disease?
SCC in situ
Red/brown scaly plaques.
Intraepidermal SCC
More common in elderly females.
Red scaly patch. Often occur in sun-exposred areas such as lower limbs.
Management of Bowen’s Disease?
As for AK
- Cautery
- Cryo
- 5-FU
- Imiquimod
Keratoacanthoma?
Benign epithelial tumour.
Fast-growing, dome-shaped with a keratin plug.
Looks like a volcano or crater filled with keratin.
Usually regress but may be excised.
Look like a volcano- crater.
What is a BCC - Basal Cell Carcinoma?
- Commonest Cancer
- Pearly nodule with rolled telangiectatic edge.
- May ulcerate
- Typically on face in sun-exposed area
Above ling from tragus –> angle of mouth.
Can be called a rodent ulcer.
Morphoeic BCC usually is associated more extensive spread than nodular BCC.
Therefore need Mohs micrographic surgery to manage it. Important in cosmetically sensitive areas, where amount of skin removed should be minimised.
What is the behaviour of a BCC?
- Low-grade malignancy - very rarely metastasis
- Locally invasive
Management of BCC?
Do a diagnostic punch biopsy taken if treatment other than standard surgical excision is planned.
Excision
- Mohs: complete circumferential margin assessment using frozen section histology.
- Managed with surgical removal, curettage, cryotherapy, topical cream.
Epidemiology of psoriasis?
Prevalence: 2% of Caucasians Age: peaks in 20s to 50s Sex: F=M Genetics: 30% have FH - Genetic predisposition
What is the pathology of Psoriasis?
- Type 4 hypersensitivity reaction
- Epidermal proliferation
T-cell driven inflammatory infiltration - Histo
Acanthosis: thickening of epidermis
Parakeratosis: nuclei in stratum corneum
Munro’s microabscesses: neutrophil
What are the triggers for psoriasis?
- Stress
- Infection: esp streps (triggers a guttate psoriasis)
- Skin trauma: Kobner’s phenomenon
- Drugs: Lithium, Antimalarials, ETOH and BETABLOCKERS, NSAIDS, ACEi, infliximab.
- Smoking
What are the signs of psoriasis?
Plaques
- Symmetrical well-defined red plaques with silvery scale
- Extensor: elbow, knee
- Flexures (no scales): axillae, groin, submammary
- Scalp, behind ears, nael, sacrum.
What are the nail changes in psoriasis?
Nail pitting
Onycholysis
Subungual hyperkeratosis
How many people with psoriasis develop seronegative arthritis?
- mono/oligo-arthritis: DIPs commonly involved
- Rheumatoid-like
- Asymmetrical polyarthritis
- Psoriatic spondylitis
- Arthritis mutilans
- May –> Dactylitis
What are the variants of psoriasis?
Guttate: transient psoriatic rash frequently triggered by strep infection. Multiple red, teardrop lesions appear on the body. Mainly on the trunk.
Pustular: commonly occurs on the palms and soles
Plaque: Most common sub-type leading to well demarcated red, scaly patches affecting extensor surface, sacrum and scalp.
Flexural: in contrast to plaque psoriasis the skin is smooth.
What are the differentials for psoriasis?
Eczema
Tinea
Seborrhoeic dermatitis (includes the nasolabial folds)
Acne rosacea - spares this area
Management of psoriasis?
Education - avoid triggers (alcohol, trauma, B-Blockers, Lithium, antimalarials, NSAIDs, ACEi)
Soap substitute - aqueous cream, dermol, epaderm ointment.
Emollients - epaderm, dermal, diprobase.
Topical therapy
- Vit D3 analogues: (works by reducing cell division) calcipotriol (1st line + steroids)
- Steroids: betamethasone (Dovobet = calcipotriol + betamehasone)
Second line: no improvement after 8 weeks offer Vit D analogue twice daily.
Third line: offer potent corticosteroid 2x daily for 4 weeks or a coal tar prep applied once or twice daily.
Using topical steroids in psoriasis?
Can lead to skin atrophy, striae + rebound symptoms.
Systemic side-effect therfore aim for 4 week break before starting another topical steroid.
Management of scalp psoriasis?
Psoriasis as a circular, white, hyperkeratotic lesion on crown of his head.
Potent topical corticosteroids used once daily for 4 weeks.
If no improvement after 4 weeks either use a different steroid or topical agent to remove adherent scale.
Other management options for psoriasis?
Narrow band UVB light. - 3x a week. Photochemotherapy is also used - psoralen + UVA light (PUVA)
- Adverse effect: Skin ageing, SCC. (PUVA increases risk of Ca)
Systemic therapy
- Oral methotrexate is 1st line.
- Ciclosporin
- Systemic retinoids
- Bio agents: infliximab, etanercept + adalimumab.
- Ustekinumab (IL-12+ IL-23)
What is the presentation of eczema?
Extremely itchy
Poorly demarcated rash
- Acute: oozing papules and vesicles
- Subacute: red and scaly.
Chronic eczema –> Lichenification with skin thickening with exaggeration of skin markings.
What is the pathology of eczema?
Epidermal spongiosis
What is the cause of eczema?
FH of atopy common
Specific allergens
- House dust mite
- Animal dander
Diet: e.g diary products
What is the presentation of eczema?
Face: esp around eyes, cheeks Flexures: Knees, elbows May become 2ndry infection - Staph = fluclox - HSV --> Aciclovir
Associations of eczema?
Asthma
Hay fever
Investigations of eczema?
increased IgE
RAST testing: identify specific ag.
What is irritant contact dermatitis?
Everyone is susceptible to irritants
Causes: detergents, soaps, oils, solvents, venous stasis
What is allergic contact dermatitis?
Type IV hypersensitivity reaction - Common allergens Nickel: jewellery, watches coins Chromates: leather Lanolin: creams, cosmetics
- Location: correlated sharply with allergen exposure
Investigation with Patch testing - various allergens are applied to patient’s back, and skin assessed at 48hr.
Skin Patch = Delayed hypersensitivity.
Skin Prick = Type 1 immediate.
What is adult seborrhoeic dermatitis?
Itchy, red, scaly rash that affects the face and scalp.
Causes: overgrowth of skin yeasts (malasseiza)
Location: Scalp (dandruff), eyebrows, cheek, nasolabial folds
- Associated with HIV and Parkinson’s
Management :
Scalp disease management:
- hair shampoo containing zinc pyrithione.
- Then use ketoconazole.
- Then selenium
Face and body -
mild topical steroids/antifungal - ketoconazole
- topical corticosteroid.
What is the management of atopic eczema?
- Avoid triggers e.g soap
- Soap substitute: Aqueous cream, dermol cream, epaderm ointment
- Emollients: Epaderm, Dermol, Diprobase, Oilatum (bath oil)
- Topical therapy - if using steroid - do emollient first, then wait 30 mins before applying topical steroid.
Steroid: 1% Hydrocortisone: fac, groin.
Eumovate: can use briefly (<1 weeks) on face
Betnovate
Dermovate: very strong, brief use on thick skin - palms, soles.
2nd line
- Topical tacrolimus
- Phototherapy
- Ciclosporin or azathioprine
Pruritus differentials?
Generalised pruritus - CRF - Cholestasis - Haematological Polycythaemia Hodgkin's Leukaemia Iron deficiency
Endocrine
- DM
- Hyper/hypothyroidism
- Pregnancy
- ‘senile’ pruritus
- urticaria
-skin disorders: eczema, scabies, psoriasis,
pityriasis rosea
Pruritus in dermatological disease?
Eczema
Urticaria
Scabies
Dermatitis herpetiformis
What is tinea infection
A superficial mycosis caused by dermatophytes
- Microsporum
- Epidermophyton
- Trichophyton
What is the presentation of tinea?
- Round scaly lesion
- Itchy
- Central clearing
- Scalp, body, foot, groin, nails.
Types of tinea?
Tinea Capitis - scalp
Tinea Corporis - trunk, legs, arms
Tinea Pedis - feet
What is tinea capitis?
Scalp ringworm
- Cause of scarring alopecia mainly seen in children. Causes a scarring alopecia.
- If untreated a raised, pustular spongy/boggy mass called a kerion may form.
- Most common cause is trichophyton tonsurans in the UK + USA.
- May also be caused by microsporum canis from cats or dogs.
- Diagnosis: lesions due to microsporum canis green fluorescence under Wood’s lamp. (Scalp scraping is most useful). Trichophyton lesion
Management - griseofulvin or terbinafine
What is tinea corporis? (ringworm)
Caused by trichophyton rubrum and verrucosum
- from contact with cattle.
- Well-defined annular, erythematous lesions with pustules and papules. Raised.
- Treat with Terbinafine or imidazole such as clotrimazole, miconazole, or econazole cream
What is tinea pedis?
- Characterised by itchy, peeling skin between toes.
- Common in adolescence.
- Caused by fungi called Trichophyton.
Typically scaling, flaking and itching between the toes.
Topical imadazole/miconazole undecenoate. If this does not work,
Give oral terbinafine.
Presentation of candida infection?
Common
RFs: immunosuppression, abx, steroid inhaler.
Presentation
- Pink + white patches
- Moist
- Satellite lesions
- Mouth, vagina, skin fold, toe webs.
Management of tinea corporis, capitis?
Skin: terbinafine or topical ketoconazole
Scalp: griseofulvin or terbinafine
Nails: terbinafine
Management of candida infection?
Mouth: Nystatin
Vagina: Clotrimazole cream and pessary
What is pityriasis versicolour caused by?
Malassezia Furfur. A superficial cutaneous fungal infection caused. Dermatophyte fungal skin infection
- Most commonly affects the trunk
- Patches may be hypopigmented, pink or brown (versicolor).
- More noticeable following a suntan.
- Scale is common
- Mild pruritus
- Fine white scale.
Usually on the trunk or back and is scaly in appearance.
What is the investigation of pityriasis versicolor?
Spaghetti and meatballs appearance with KOH stain.
- Predisposing factors = occurs in healthy individuals immunosuppression Malnurition Cushings
Management of Pityriasis Versicolour?
Selenium sulphate or
Ketoconazole shampoos.
What is impetigo ?
Contagious superficial skin rash caused by S.aureus.
Presentation of impetigo?
- Age: peak @2-5 yrs.
- Honey-coloured crust on erythematous base
- Common on face.
- Occur in the flexures and limbs not covered by clothing.
Management of impetigo?
- Mild: Topical abx (fusidic acid, mupirocin).First line.
- 2nd line = topical retapamulin
- More severe: oral fluclox PO
- Children should be excluded from school until the lesions are crusted and healed or 48hrs after commencing antibiotic treatment.
MRSA = Topical mupirocin (Bactroban)
Extensive
- Oral flucloxacillin
- Oral erythromycin if penicillin allergic
- Children should be excluded from school until lesions are crusted and healed or 48hrs after antibiotic treatment.
What is erysipelas?
- Sharply defined superficial infection of S.pyogenes. Superficial cellulitis affecting face.
- Often affects the face
- High fever + increased WCC
Management
- Benpen IV
- Pen V and fluclox PO.
What is Cellulitis?
Acute infection of skin and soft tissue - inflammation of skin + subcut tissues
Causes: B-haemolytic Strep + Staph A.
What is the primary cause of cellulitis?
B-Haemolytic Strep (Strep Pyogenes) + staph Aureus.
What is the presentation of cellulitis?
- Deeper and less well defined than erysipelas
- Pain, swelling, erythema and warm
- Systemic upset
- ± lymphadenopathy