Dermatology

Question 1

Discuss the difference between an incisional and excisional skin biopsy

Answer 1

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.

Question 2

Discuss the indications for a shave biopsy, punch biopsy and elliptical incisional biopsy

Answer 2

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

Question 3

Discuss how bases functions and different types that can be used for dermatological conditions

Answer 3

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

Question 4

List the common topical dermatological medications, their mechanism of action, and some adverse effects

Answer 4

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

Question 5

List some of the oral dermatological agents, their mechanism of action and some adverse effects

Answer 5

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

Question 6

Discuss the indications for intralesional steroid injections

Answer 6

Indications:

• hypertrophic or keloid scar
• alopecia areata
• acne cyst
• lichen planus

Adverse effects:

• local skin atrophy
• hypopigmentation
• sterile or infective abscess

Question 7

Define the following terms:
Macule -
Patch - 
Papule - 
Plaque -
Nodule -
Tumour -
Vesicle - 
Bulla -
Cyst -
Pustule -
Erosion -
Ulcer - 
Indurated - 
Scar - 
Wheal - 
Crust -
Scale -
Lichenification -
Fissure -

Answer 7

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

Question 8

Provide the differential for different skin groupings

Answer 8

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

Question 9

Discuss the presentation and management of exanthematous eruption

Answer 9

Drugs: penicillins, sulfonamides (Septra), phenytoin
Presentation:
- erythematous maculopapular eruptions
- erythematous patch or plaque -> generalized exfoliative dermatitis
Location: trunk
Management: stop drug

Question 10

Discuss the presentation and management of fixed drug eruptions

Answer 10

Medications: antimicrobials, barbiturates, phenolphthalein, NSAID
Presentation: sharply demarcated erythematous oval patch
Location: face, mucosa, genital, acral
Management: stop drug

Question 11

Discuss the presentation and management of photosensitive drug eruptions

Answer 11

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

Question 12

Discuss the presentation and management of Steven-Johnson Syndrome

Answer 12

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

Question 13

Discuss the presentation and management of drug hypersensitivity syndrome

Answer 13

Medications: sulfonamides, anti-convulsants
Presentation:
- begin 10 days following exposure
- fever -> bright red exanthematous eruption -> internal organ involvement
Management: stop medication

Question 14

List two methods to differentiate between benign and malignant skin cancer

Answer 14

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

Question 15

List the risk factors for skin cancer

Answer 15

no SPF is a SIN

• Sun exposure
• pigment traits (blue eyes, fair/red hair, pale complexion)
• freckling
• skin reaction to sunlight
• immunosuppressant
• nevi

Question 16

Discuss the presentation and management of basal cell carcinoma

Answer 16

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

Question 17

Discuss the presentation and management of squamous cell carcinoma

Answer 17

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

Question 18

Discuss the presentation and management of melanoma

Answer 18

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

Question 19

List the different forms of melanoma

Answer 19

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

Question 20

Discuss the differences between bullous pemhigoid, dermatitis herpetiform, and pemphigus vulgaris

Answer 20

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

Question 21

Discuss the skin lesions for bullous pemphigoid, dermatitis herpetiform, pemphigus vulgaris

Answer 21

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

Question 22

Discuss the presentation and management of erythema multiforme

Answer 22

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

Question 23

Discuss the presentation and management of psoriasis vulgaris

Answer 23

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

Question 24

Discuss the other forms of psoriasis

Answer 24

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

Question 25

Discuss the presentation and management of lichen planus

Answer 25

Epidemiology: associated with hep C infection
Presentation:
- 7 P’s: purple, pruritic, polygonal, peripheral, papules, planar, penis (mucosa)
- Wickham striae: reticulate white-grey lines over surface
Location: flexor, mucous membranes,
Management:
- antihistamine
- localized: topical corticosteroid or intradermal steroid injection
- systemic: phototherapy, oral retinoids, systemic steroids, immune modulators

Question 26

Discuss the presentation and management of pityriasis rosea

Answer 26

Presentation:
- onset of herald large pink patch with scale and clear centre -> red-pink macules and patches following parallel to ribs with Christmas tree pattern
Management: spontaneously resolve in 6-12 weeks

Question 27

Discuss the presentation and management of granuloma annulare

Answer 27

Presentation: self-limited asymptomatic disease that only have cosmetic disfigurement
- violaceous, erythematous, skin coloured annular or arcuate papule or plaque
Location: dorsal hands, fingers, feet
Management:
- localized: watchful waiting, possible steroids
- generalized: PUVA, systemic steroids, isoretinoin

Question 28

Discuss the presentation and management of acne vulgaris

Answer 28

Epidemiology: onset at puberty
Presentation:
- Closed comedome: whitehead
- Open comedome: blackhead
- Inflammatory papule: red, follicular papule
- Inflammatory pustule: red, superficial peri-follicular pustule
- Inflammatory cystic nodule: red, deeper lesion >5mm that leads to scarring
Location: face, neck, upper chest and back
Management:
- topical treatment for mild to moderate papulopustular: salicylic acid, retinoids creams (most effective for comedome but take few weeks to work), benzoyl peroxide creams (antibacterial), topical antibiotics (clindamycin or erythromycin)
- systemic antibiotics for moderate-severe pustular acne, papulopustular acne or cysts: tetracyclines or erythromycin (kill P. Acnes bacteria)
- systemic isoretinoin for severe resistant or nodulocystic acne: accutane (inhibit sebaceous gland activity)
- intralesional steroid injection for nodulocystic acne: decrease inflammation and reduce scarring

Question 29

What are the risk factors for acne vulgaris?

Answer 29

Cosmetics
Chronic rubbing
Stress
Diet high in simple carbohydrates
Medication (corticosteroids, androgen, lithium)

Question 30

Discuss the presentation and management of peri-oral dermatitis

Answer 30

Epidemiology: females between 15-40
Presentation: erythematous micropapules that can become confluent, form inflammatory plaques
Location: symmetrical peri-oral/nasal/orbital
Management: topical metronidazole or systematic tetracycline

Question 31

Discuss the presentation and management of rosacea

Answer 31

Presentation:
- dome shaped red papule and pustule on erythematous skin
- no comedomes
- can have associated lymphedema or blepharitis/conjunctivitis
- vascular skin lesions leading to flushing and background redness
Location: central face, scalp, neck, upper body
Management:
- avoidance of topic corticosteroids and triggers
- topical therapy without ocular involvement: methronidazole (1st), clindamycin or erythromycin (2nd)
- systemic or with ocular involvement: tetracycline (1st), erythromycin or clindamycin (2nd)

Question 32

What are the risk factors for rosacea exacerbation?

Answer 32

Temperature
Sun
Stress
Alcohol
Caffeine
Spices

Question 33

Discuss the presentation and management of non-bullous and bullous impetigo

Answer 33

Epidemiology: children 2-6
Organism: Staph aureus in 70% (bullous 100%), group A streptococcus
Presentation:
- Vulgaris: vesicle/pustule that progresses to golden yellow honey-crusted lesion surrounded by erythema
- Bullous: scattered large flaccid superficial clear bullae with yellow or slightly turbid fluid on erythematous or itchy skin (no crust)
Location: face, buttocks, arms, legs
Management:
- self-resolves in 2 weeks
- skin care with wet compresses and Mupirocin for 7-10 days
- widespread can provide Keflex or cloxacillin

Question 34

Discuss the presentation and management of erysipelas

Answer 34

Organism: group A streptococcus (strep pyogenes)
Presentation:
- confluent erythematous sharp raised edge warm plaques with sharp demarcated borders
- fever, chills, malaise, lymphadenopathy
Location: face, legs
Treatment: PO or IV antibiotics for 10-14 days
- penicillin, cloxacillin, or cephazolin are 1st line

Question 35

Discuss the presentation of folliculitis

Answer 35

Organism: Staph aureus
Presentation: dose shaped pustule at head of hair follicle on erythematous skin base that is evenly spaced
Location: scalp, shoulder, chest, upper back
Management: topical antiseptic (hibitane) and topical antibiotic (Mupirocin)

Question 36

What is a furuncle and carbuncle and how does their management differ?

Answer 36

Furuncle: abscess involving hair follicle
- red hot tender inflammatory nodule with central yellow point. Rupture to drain pus
Carbuncle: cluster of furuncle
- deep seated abscess with coalescing furuncle which drain through multiple sinus tracts

Management: irrigation and drainage, hot compress, local antiseptic and antibiotic

Question 37

Discuss the presentation and management of tinea versicolor

Answer 37

Epidemiology: young adults
Organism: pityrosporum orbiculare
Presentation: brown/pink/hypopigmented macules and geographic coalescing patches, dry scaling
Location: back, upper trunk
Diagnosis: KOH test show short curved hyphae and clusters of round conidia
Management: selenium sulphide or zinc pirythione (Head and Shoulders), Ketocanozole PO

Question 38

Discuss the presentation and management of tinea capitis

Answer 38

Epidemiology: Black children
Organism: trichophytan tonsurans, microsporum canid, microsporum audoini
Presentation: round patchy scales of alopecia with broken-off stubby hair, kerion
Location: scalp, eye lashes, eyebrows
Investigations: Woods light shows green fluorescence of microsporum, KOH show infected hair cells with hyphae
Management: topical antifungal (selenium sulphide shampoo, ketocanozole) to decrease spread and oral antifungals (lamasil) to clear infection

Question 39

Discuss the presentation and management of tinea corporals

Answer 39

Epidemiology: children, especially those with infected pets (farm)
Presentation: pruritic, scaly and round plaque that is well demarcated with central clearing and erythematous margin
Location: trunk, face, limbs
Investigation: KOH show hyphae
Management: topical antifungal q12h for 2-3 weeks (ketocanozole)

Question 40

Discuss the presentation and management of tinea cruris

Answer 40

Epidemiology: affect adult males
Organism: trichophytan rubrum or mentagrophytes, epidermophytam floccosum
Presentation: pruritic, erythematous, dry or macerated scaly patch or plaque with well defined curved border
Location: medial thigh
Investigation: KOH show hyphae
Management: topical antifungal q12h for 2-3 weeks

Question 41

Discuss the presentation and management of tinea perish

Answer 41

Epidemiology: most common, with risk from heat/humidity and occlusive footwear
Organisms: trichophyton rubrum or mentagrophytes, epidermophytan floccosum
Presentation: pruritic scaling and/or maceration of web spaces and powdery scaling of soles
- acute: erythema, vesicles or bullae, scaling
- chronic: non-pruritic pink scaling keratosis
Investigations: KOH show hyphae
Management: topical antifungals q12h for 2-3 weeks

Question 42

Discuss the presentation and management of tinea unguium

Answer 42

Organism: trichophytan rubrum
Presentation: opaque, yellow, thickened and crumbly nail with accumulation of subungual hyperkeratotic debris
- have prior tinea pedis infection
Investigation: KOH show hyphae
Management: oral antifungal (lamosil) for 6 weeks for fingernail and 12 weeks for toenail

Question 43

Discuss the presentation and management of candidiasis

Answer 43

Organism: candidia albicans
Presentation: smooth, soft creamy white colonies with white curdy eruptions
- have macerated/eroded erythematous patches and satellite pustules peripherally
Location: corner of mouth, tongue, esophagus
Investigation: KOH show budding yeast cells and sausage like pseudohyphae
Management:
- skin: topical antifungal with hydrocortisone (Nystatin)
- systemic: oral or IV antifungal

Question 44

What are the risk factors for candidiasis?

Answer 44

Obesity
Pregnancy
Diabetes
Addison’s
Immunosuppression (malignancy, immunosuppressants)
Medication (oral contraceptive, antibiotics, corticosteroid)

Question 45

Discuss the presentation and management of HSV 1&2

Answer 45

HSV1: primary infection causes gingivostomatitis and then reactivation leading to grouped vesicles on erythematous base at mucocutaneous junction
- prodrome of pain, numbness
- location: face, lips
- treatment: antiviral during prodrome
HSV2: multiple vesicles on erythematous base
- incubation of 2-20 days following transmission
- location: genitalia
- investigation: tzanck smear with Giesma stain, definitive through culture of vesicular fluid
- treatment: topical treatment and oral antiviral

Question 46

Discuss the presentation and management of VZV

Answer 46

Primary: incubation of 10-23 days
- vesicle -> pustule -> crust with lesions present in all three stages at same time
- location: face, scalp, trunk, extremeties
- management: symptomatic
Secondary: dormant in dorsal root ganglia
- prodrome of tingling, burning, itching in thoracic dermatome for 0-4 days
- erythematous vesiculopustular rash that may ulcerate and crust in 4-11 days
- post-herpetic neuralgia following treated with pregabalin
- management: topical management, NSAIDs, oral antivirals 72 hours before onset, vaccine

Question 47

Discuss the presentation and management of HPV

Answer 47

Presentation: exophytic, frond (leaf like) or cauliflower
- HSV1,2,4,10 verruca plantaris or palmaris
- HSV3,10 verruca planae (flat) on face, dorsal hands
- HPV6,11 condyloma accumulata on genital or perianal
- HPV16,18 cause cervical cancer
Treatment:
- Skin: 1st line is salycyclic acid, 2nd line liquid nitrogen cryotherapy, 3rd line is surgical excision
- anogential: 1st line is topical imiquimod, podohyllotoxin, 2nd line is trichloroacetic acid or electrodissection/surgery/CO2 laser

Question 48

Discuss the presentation and management of scabies

Answer 48

Organism: parasitic sarcopetes scabies
Presentation: pruritic burrows and grey lines from skin, widespread papular eruptions
Location: armpits, wrist, hands, groin, periumbilical, buttocks, knees, ankles, toes
Investigation: skin scrapping showing mites, eggs, pellets
Treatment: topical treatment left overnight and then repeated in 3-7 days (Permetrin 5% cream)