Dermatology Flashcards
Discuss the difference between an incisional and excisional skin biopsy
Incisional: biopsy that takes portion of epidermis, dermis and subcutaneous fat. Used for diagnostic purposes
Excisional: biopsy that takes entire lesion including the epidermis, dermis and subcutaneous fat with a 1-2mm margin. Is diagnostic and therapeutic.
Discuss the indications for a shave biopsy, punch biopsy and elliptical incisional biopsy
Shave biopsy: shave off fragment of skin for epidermal lesions with no further extension - warts - papilloma - superficial BCC or SCC - actinic keratoses Punch biopsy: core of 1-4mm tissue of the epidermis, dermis and subcutaneous fat for lesions requiring only dermal or subcutaneous tissue for diagnosis - inflammatory lesions - bullous lesions - dysplastic nevi too large for excision - nodule - scalp or hair biopsy Elliptical excisional biopsy: similar to punch biopsy excepts takes 1-3mm margin of normal tissue. - best biopsy method for melanoma
Discuss how bases functions and different types that can be used for dermatological conditions
Allow percutaneous absorption through passive diffusion
Types:
Lotions - best for wet exudative or acute dermatoses
Creams - best for dry or chronic dermatoses
Ointments - best for dry skin as are lubricating
Paste - best for dry oozing sites, but increases risk of maceration as absorbs moisture
Gels
Powder - prevent maceration and decrease friction
List the common topical dermatological medications, their mechanism of action, and some adverse effects
Topical steroids:
- have anti-inflammatory, immunosuppressive, vasoconstrictive and anti-proliferation effects
- skin and subcutaneous tissue atrophy, increased risk of skin infection, peri-oral dermatitis, contact dermatitis, hypopigmentation, ecchymosis, telengectasia purpura, tachyphylaxis, suppressed hypothalamic-pituitary-adrenal axis, ocular hypertension and glaucoma
Vitamin D:
- unknown
- burning and itching skin
Immune modulator (imiquimod):
- activate TLR-7 leading to immune activation
- erythema, ulceration, edema
Anti-parasitic
- neurotoxin to parasites
- drug hypersensitivity, burning and pruritis
Tacrolimus:
- macrolide calcineurin inhibitor which inhibits T cells
- burning
List some of the oral dermatological agents, their mechanism of action and some adverse effects
Antivirals:
- inhibit viral replication
- headache, nausea, abdominal pain, diarrhea
Immunosuppressants
- inhibit T cell activity
- immune suppression, renal failure, hypertension
Vitamin A for Acne:
- unknown
- night blindness, dry mucous membranes, depression, suicide, myalgia, teratogenic
DMARD (methotrexate):
- inhibit folate synthesis, inhibit DNA replication and T cell activation
- immune suppression, hepatic toxicity, teratogenic
Antibiotic for Acne (tetracycline):
- inhibit microbial ribosome to stop bacterial synthesis
- hepatic toxicity, renal failure, teratogenic and <12
Discuss the indications for intralesional steroid injections
Indications:
- hypertrophic or keloid scar
- alopecia areata
- acne cyst
- lichen planus
Adverse effects:
- local skin atrophy
- hypopigmentation
- sterile or infective abscess
Define the following terms: Macule - Patch - Papule - Plaque - Nodule - Tumour - Vesicle - Bulla - Cyst - Pustule - Erosion - Ulcer - Indurated - Scar - Wheal - Crust - Scale - Lichenification - Fissure -
Macule - flat lesion <1cm
Patch - flat lesion >=1cm
Papule - raised lesion <1cm
Plaque - raised lesion >=1cm
Nodule - deep, palpable lesion <1cm
Tumour - deep, palpable lesion >=1cm
Vesicle - fluid filled lesion <1cm
Bulla - fluid filled lesion >=1cm
Cyst - epithelial lined collection containing semi-solid or fluid material
Pustule - elevated lesion containing purulent fluid
Erosion - disruption of the skin involving the epidermis alone (will not scar)
Ulcer - disruption of the skin that extends into the dermis or deeper (will scar)
Indurated - lesion that is hard or firm
Scar - replacement fibrosis of dermis and subcutaneous tissue
Wheal - papule or plaque that is transient and blanchable (formed by edema in dermis)
Crust - dried fluid originating from the lesion
Scale - excess keratin
Lichenification - thickening of skin and accentuation of normal skin markings
Fissure - linear slit-like cleavage into the skin
Provide the differential for different skin groupings
Acneiform eruption: comedomes, papules, pustules, nodule - acne vulgarisms - peri-oral dermatitis - rosacea Eczema: pruritis, painful skin lesion (vesicle -> scaling and crusting -> lichenification and fissures) - seborrheic dermatitis - atopic dermatitis - contact dermatitis Papuloquamous: papule and plaques - lichen planus - pityriasis rosea - psoriasis Vesiculobullous: vesicles, bullae - bullous pemphigoid - dermatitis herpetiform - pemphigus vulgaris - porphyria cutanea tarda
Discuss the presentation and management of exanthematous eruption
Drugs: penicillins, sulfonamides (Septra), phenytoin
Presentation:
- erythematous maculopapular eruptions
- erythematous patch or plaque -> generalized exfoliative dermatitis
Location: trunk
Management: stop drug
Discuss the presentation and management of fixed drug eruptions
Medications: antimicrobials, barbiturates, phenolphthalein, NSAID
Presentation: sharply demarcated erythematous oval patch
Location: face, mucosa, genital, acral
Management: stop drug
Discuss the presentation and management of photosensitive drug eruptions
Medications: thiazides diuretics, doxycycline, chlorpromazine
Presentation:
- phototoxic where have exaggerated sunburn
- photo allergic where have eczamatous reaction that spread to areas not exposed to sunlight
Management: avoid prolonged sun exposure, stop medication
Discuss the presentation and management of Steven-Johnson Syndrome
Medications: NSAID, sulfonamides, beta-lactams, anti-metabolite, corticosteroids, anti-convulsants
Severity:
- <10% of body surface exposed it is mild with 5% risk of mortality
- 10-30% of body surface area exposed it is moderate
- >30% of body surface area exposed it is severe and has >30% mortality. Toxic epidermal necrolysis
Presentation:
- 2-3 days following exposure and lasts for 4-6 weeks
- prodrome of fever and URTI
- red-blue macules with cutaneous blistering
- sheet like epidermal detachment
- Nikolsky’s sign where rubbing leads to exfoliation and rapid blistering
Location: trunk and face
Management:
- admit, possibly under burn unit
- IV fluids
- prophylactic antibiotics
- IVIG
- debridement of necrotic tissue
Discuss the presentation and management of drug hypersensitivity syndrome
Medications: sulfonamides, anti-convulsants
Presentation:
- begin 10 days following exposure
- fever -> bright red exanthematous eruption -> internal organ involvement
Management: stop medication
List two methods to differentiate between benign and malignant skin cancer
ABCDE Rule:
- Asymmetric
- Borders are irregular
- colours are multiple
- Diameter >6mm
- Evoluation in colour, size or shape over short time
7 Point Checklist:
- Major Criteria (2 points): change in size, irregular shape, irregular colour
- Minor criteria (1 point): largest diameter >=7mm, inflammation, oozing, change in sensation
List the risk factors for skin cancer
no SPF is a SIN
- Sun exposure
- pigment traits (blue eyes, fair/red hair, pale complexion)
- freckling
- skin reaction to sunlight
- immunosuppressant
- nevi
Discuss the presentation and management of basal cell carcinoma
Pathophysiology: arises from the basal cells, least aggressive
Presentation: nodulo-ulcerative type
- papule/plaque/nodule with white translucent shiny scale
- well defined borders
- telengectasia
Management:
- superficial on trunk: imiquimod
- face: Mohs excision
- shave excision + electrodissection and currettage
Discuss the presentation and management of squamous cell carcinoma
Pathophysiology: arises from the supra-basalar stem cells in epidermis Presentation: - indurated, erythematous nodule/plaque with surface crust - eventually ulcerated - more scales - volcano morphology Location: face, ears, scalp, forearms Management: surgical excision
Discuss the presentation and management of melanoma
Pathophysiology: arise from melanocytes on epidermal basement membrane or pre-existing nevi
Presentation:
- dark pigmented lesion that can be flat, raised or nodular
- asymmetric, ill-defined borders, multiple colours, diameter >6mm
- ugly duckling rule where melanoma appears abnormal from other nevi
Prognosis: TMN staging
- T: breslow depth is from stratum granulosum to deepest point of invasion. Most important factor where depth >1mm into dermis is poor prognosis
Management:
- excisional biopsy
- surgical removal with possible chemotherapy and radiotherapy
List the different forms of melanoma
Lentigo Melanoma
- 2-6cm tan/brown/black flat macule or patch
Lentigo Maligna Melanoma
- flat brown staining growing lesion with loss of skin surface markings
Superficial Spreading Melanoma
- spread laterally
- irregular, indurated enlarging plaques with red, white or blue discolouration
- lesion ulceratd and bleed
Nodular melanoma
- grow vertically
- uniformly ulcerated blue-black and sharply demarcated nodule or plaque
Acrolentiginous Melanoma
- ill-defined dark brown, blue-black
- palmar, plantar or sublingual
Discuss the differences between bullous pemhigoid, dermatitis herpetiform, and pemphigus vulgaris
Antibody: - IgG - IgA - IgG Site: - basement membrane - dermal - intrapepidermal Infiltrate: - eosinophils - neutrophils - eosinophils and neutrophils Management: - systemic steroids, immunosuppressants, tetracycline - gluten-free diet, dapsone - high dose steroids, immunosuppressants Association: - Malignancy - gluten enteropathy, thyroid disease, intestinal lymphoma - malignancy with paraneoplastic syndrome
Discuss the skin lesions for bullous pemphigoid, dermatitis herpetiform, pemphigus vulgaris
Bullous pemphigoid
- prodrome of urticareal papule and plaque eruption
- pruritic, burning, subepidermal bullae containing serous or hemorrhagic fluid on an erythematous or normal skin base
- heal without scarring
- on flexor surfaces
Dermatitis Herpetiform
- grouped papules/vesicles/urticarial wheals on erythematous base that burn and are pruritic
- extensor surfaces
Pemphigus Vulgaris
- onset of mouth lesion followed by skin lesions in 6-12 months
- flaccid non-pruritic epidermal bullae/vesicles on erythematous or normal skin base
- Nikolsky’s sign
- Asboe-Hansen sign (force applied to bullae they extend laterally)
- on mouth, scalp, face, chest, axillae, groin
Discuss the presentation and management of erythema multiforme
Cause:
- infection: HSV, mycoplasma pneumonia,
- drug reaction: penicillin, sulfonamides, anticonvulsants
Presentation:
- present within 72 hours and last for 7 days
- macule/papules with central vesicles
- target lesions
- weakness, malaise
Location: dorsal hands, palms, soles, mucous membranes
Management:
- symptomatic with oral antihistamine
- cool compress
- topical steroids
- prophylactic acyclovir if multiple recurrences
Discuss the presentation and management of psoriasis vulgaris
Epidemiology: mean age is 33
Presentation:
- well circumscribed erythematous silvery scaled plaques
- can be pruritic leading to erosion and fissure
- Auspitz sign: punctate bleeding spots when psoriatic scales are scraped off
Locations: scalp, extensor elbow, extensor knee, lumbosarcral, umbilical
Severity:
- mild <5% total body surface area
- moderate: 5-10%
- severe: >10%
Management;
- topical treatment for mild: corticosteroid creams for 2-4 weeks
- UVB and topical for moderate: corticosteroid cream in combination with UVB. Can use potent corticosteroid for 2-4 weeks and then intermittently on weekends and vitamin D cream topically every day
- systemic therapy plus topical for severe: UVB and methotrexate is first line, adalimumab is second line
Discuss the other forms of psoriasis
Guttate psoriasis: widespread erythematous scaly plaques with teardrop shape
Generalized pustular: widespread painful erythema with sterile pustules
Palmoplantar: yellow-brown sterile pustules on palms/soles which can dry into erythematous scaling plaques or fissures
Erythrodermic: erythema of entire body with scale and edema
Nail: fingernail pitting, onycholysis, oil spots, hyperkeratosis, nail plate dystrophy, thickening, dullness
Arthrtitis: asymmetric oligoarthritis with dactylitis and enthesitis
