Dermatology Flashcards
What is acne vulgaris?
Hormonal inflammatory pilosebacious disease - Comedones (open are black heads and closed are white heads)
Papules (no pus), pustules (pus)
Nodular pseudocysts
Scarring
Onset in adolescence
genetic
Treatment of acne vulgaris
Mild disease: topical Abx
Moderate: topical ABx + oral ABx . If this fails after 3-6mo, add antiandrogens
Severe: Systemic retinoids (isoretinoin = Roacutaine)
Characteristics of rosacea
How is this different from acne?
Tendency to flush/blush
+/- burning sensation
Florid ruddy complexion all the time - affecting convexities of face
+ Papules, pustules
Telangiectasia
Worse w vasodilation, wind, stress etc
Doens’t have comedones, unlike acne
Complications of rosacea
Rhinophyma in men (swelling and hypertrophy of subcutaneous tissue of nose)
Ocular: conjunctivitis, keratitis, iritis
Treatment rosacea
No cure - avoid triggers (sunlight)
Makeup, moisturiser, sunscreen
Topical Abx: Metronidazole and tetracycline
Systemic doxyclycine or systemic retinoids if inflammatory ethology
Vascular laser if vascular etiology
Ablative laser if rhinopehyma
TOPICAL STEROIDS MAKE THINGS WORSE!
Contact dermatitis - compare the 2 types
Irritant (non-immune) - redness, dry skin, fine scale, burning
- commonly due to nickel in belt buckles
Allergic (t4 hypersensitivity) - vesicular, redness, swelling, itchy .
- usually flexor surfaces
- commonly due to poison ivy.
Eczema vs Psoriasis
Signs
Eczema: flexor
Acute - weepy, crusting, red, blistered lesions. diffuse.
Chronic - dry thickened, scaly and itchy lesions
Psoriasis: extensor
Salmon pink erythematous plaques, with silvery scales
Eczema vs Psoriasis
HS response
Eczema - Type 4
Psoriasis - Type 1
Eczema treatment
chronic vs acute flare
E:
Prevention:
- avoid triggers (extremes of temp, dry/extreme heat, soap and detergents)
- regular emollients
- warm/cool (soap-free) baths, wet compress
- if above doesn’t work, can try low dose topical steroid
Acute flare:
- Potent topical steroids (mild ones for face)
- Topical/oral abx if suspect bacterial infection (golden crusty)
Severe: oral steroids or immunosuppressants (methotrexate, azathioprine etc)
Eczema vs Psoriasis
exacerbators
E - worse in heat
P - worse in cold
Which type of psoriasis is associated w strep pharyngitis (strep throught)?
1-2 weeks after strep URTI.
Guttate psoriasis. (small plaque psoriasis, almost looks like red mosquito bites)
What is erythema multiform characterised by?
Target lesions (macules, papules) w central vesicles start on dorsum of hands and feet first then spread towards trunk. Mucus membrane involvement
Often triggered by infections
Treatment of Erythema multiforme vs Steven Johnson syndrome
EM:
- TX: Do nothing -> Self-healing within 2 weeks
- SX treatment: antihistamines for itch and mouthwash (oral steroids if severe) for oral pain
SJS:
- TX: hospitalisation w supportive care + STOP CAUSATIVE MEDS + skin care (wet dressings, abx etc)
What is Stven johnson syndrome characterised by?
Starts on TRUNK, then spreads to limbs. + mucus membrane
Targetoid lesions (like target lesion but no vesicle in centre)
Blisters
Sheet-like epidermal detachment on contact of skin.
prodrome is flu-like illness up to 14 days
What is Steven johnson syndrome caused by?
Adverse effect of medication
What is a keratoacanthoma?
What is it’s natural history?
Tx?
- Low grade SCC
- Spontaneous regression within 1 year with scar
- Tx: excision
What is the significance of solar or actinic keratosis ?
What are red flags?
What do you do about them?
10% can develop to SCC
Watchful waiting
If suspicious for transformation to SCC (growing, hyperkeratotic, TENDER):
Cryotherapy
Topical medications (5-Fu, imiquimod)
Surgical excision
Actinic keratosis:
Where are they generally found and what are key features?
Found on sun exposed skin - face, scalp, forearms and hands
Scaly erythematous lesions, sand-papery texture +/- actinic horn
What is Bowen’s disease?
Appearance?
SX?
What is the significance of them?
Intraepithelial SCC (early non-invasive stage of SCC = full thickness epithelial dysplasia without breaching BM)
Appearance: perisistant red-brown scaly patch, NOT indurated
Location: sun exposed sites, particularly lower limbs!
SX: may be itchy/painful/bleed but often asymptomatic
Significance: 5% progress to invasive SCC.
MX of Bowen’s disease
Excision and biopsy if suspicious
Topical 5FU or imiquimod
Topical meds for removing skin lesions
5-fluorouracil cream
Imiquimod cream (IFN)
Photodynamic therapy
BCC
- level of invasion
- where are they found?
Local invasion (almost never metastasise)
Found on face
BCC characteristics
Pearly/transulent firm nodule
Rolled edges
+/- central indentation or ulceration (“rodent ulcers”)
Telangiectic border (red) painless bleeding
Indolent growth
SCC characteristics
Erythematous nodule or plaque
Hyperkeratotitic surface crust (keratinocyte proliferation)
Ulceration, bleeding
Grows quickly, over weeks-months
May be tender to palpation
SCC
- level of invasion
- where are they found?
- More likely to spread than BCC (to regional lymph nodes first)
- Sun exposed sites
Management of SCC
COMPLETE wide local excision with biopsy +/- adj. radiotherapy
Not for surgery: radiotherapy alone
lifelong follow up
Descibring skin lesions ABCDE
Asymmetry Borders (irregular) Colour (variated) Diameter (>6mm) Evolution
Risk factors for melanoma
> 5 dysplastic nevi
100 congenital nevi
Fair skin, red hair
PHX/FHX of melanoma
frequent blistering sunburns
IX and Treatment of melanoma
IX: wide excisional biopsy
MX: surgical excision +/ high dose IFN +/- chemo +/- radiotherapy
risk factors SCC
Chronic sun exposure Ionising radiation Smoking HPV 16, 18 Immunosuppression (more aggressive, metastatic disease carrying higher rate of mortality)
WHAT WOULD you use to characterise the prognosis of melanoma?
Breslow thickness - thickness of lesion based on biopsy histology determines recommended margin for wide local excision
What do you do about a suspicious lesion if they are:
- Raised
- Flat
- Pigmented/suspicious for melanoma
Raised: shave biopsy
Flat:
- Large: Punch biopsies of most suspicious areas
- Small: Wide excision if small
Pigmented/melanoma - complete wide excision
What are the terms for fluid-filled blisters?
Vesicle <5mm
Bullae >5mm
What is a pustule and what can cause these?
Pus-containing vesicle or bullae (>5mm)
Bacterial folliculitis (staph aureus) or pustular psoriasis
What are the terms for elevated skin lumps?
Papule <5mm
Nodule >5mm
What is the term for hardening of the skin so you are no longer able to pinch it?
Systemic sclerosis
What is a scale?
Abnormal accumulation of keratin on the skin surface
DX, investigations and treatment: itchy rash with a gradually enlarging red scaly edge and clearing central pale region
Tinea Corporis (ring worm)
- Fungal infection -> skin scraping for fungal MCS
- Treat with topical anti fungal cream (imidazole)
Where can tinea infect?
Skin -> T. Corporis
Between the toes -> T. pedis
Nails -> T. Unguium
Groin -> T. Cruris
Scalp, causing hair loss -> T. Capitis (more common in children)
What is alopecia?
Common causes? list 3.
Hair loss
Common causes:
- Autoimmune
- Tinea capitis, common in children and transmitted by cats and dogs
- cutaneous lupus (irreversible hair loss)
What virus causes shingles?
Herpes Zoster Virus - Varicella Zoster sits latent in DRG and reactivates when host is immunosuppressed or stressed and causes vesicular/papular crusty rash in dermotomal pattern.
May have prodrome of neuralgic pain and tingling
Diagnosis via PCR
Systemic antiviral treatment
Which herpes viruses affect the skin?
HSV-1: cold sore.
(can be transmitted to genitals sexually causing 40% of genital herpes)
Systemic or topical antivirals
HSV-2: restricted to genital areas only; sexually transmitted
Systemic antiviral
Diagnosis via PCR
DX and TX:
- umbilicated (central white spot) skin-coloured papule, may be surrounded by eczema, can heal by scarring.
- Common disease of childhood, spread in pools and baths, spreads through families
Molluscum Contagiosum
TX:
- Preventative: take shows
- Topical salicylic acid wart paint
- Topical imiquimod cream
- Tape stripping, topical cantharidine, curettage
Treatment of warts
Destructive
- liquid nitrogen
- diathermy
- curettage
Topical
- salicylic acid
- DCP immunotherapy
- Imiquimod (genital warts)
- Tape
What sort of infection is a wart?
What sorts of warts are there?
Viral infection (HPV)
- Common wart - Verruca Vulgaris
- Plantar wart (on feet) - Verruca Planters
- Periungual (nail area and fingers)
- Plane warts (on face, looks similar to acne)
- Filiform - looks similar to a skin tag
- Anogenital - anal and penile
What organicm usually causes folliculitis and what is the treatment?
Staph aureus
Systemic ABx (flucloxaillin or cephalexin) +/- antiseptic washes
Impetigo: what is the generic name?
What organism causes impetigo and what is the characteristic appearance?
“School sores”
Staph aureus - treat w systemic flucloxaillin or cephalexin
Honey-comb crusting
Cellulitis: common causative agents
TX
Strep pneumonia! Otherwise staph aureus, staph epidermis.
Requires IV antibiotics and usually overnight admission due to systemic illness
Complications of eczema
- lichenification of skin from chronic itching and scratching
- bacterial (staph aureus) or viral (HSV) superinfection
- s/e from chronic steroid use
- eye changes from facial eczema around eyes
what is pompholyx eczema>
worse/commonly on palms triggered by excessive washing or sweating on hands
what is asteatotic eczema?
scaly and diffuse, often on legs of elderly patients w dry legs
seasonal - “winter itch” and also with heat and dryness
DDX for annular disc-like patches on skin
Discoid eczema
Tinea
Psoriasis
What sites is psoriasis generally found?
Extensor surfaces
Scalp
AnoGenital (more of a glazed appearance, less scaly)
palmar and plantar surfaces
Nails - psoriatic arthritis more likely with nail involvement
Auricular
When are the peaks of onset of psoriasis?
20s and 50s
Treatment for psoriasis
Topical steroids, topical vitD, keratinolytics
Emollients
UVB phototherapy
Systemic immunosuppressants and biologic agents
what sort of psoriasis is a medical emergency?
Generalised pustular psoriasis
- acute pustular flare w/ fever and chills
- risk of pre-renal failure, high output cardiac failure and sepsis
Acne congloblata
severe cystic acne with huge pustular white heads
Treatment of acne
Topical
- salicylic acid and retinoic acid (act to dissolve comedones)
- antibacterials
(clindamycin, benzoyl peroxide, erythromycin)
Systemic
- antibiotics (doxy, erythromycin, minocycline)
- anti-androgenic OCP for females w hormonal-type acne
- Systemic retinoids (roacutaine) - severe acne only. 60-70% Curative after 1 6-12mo course.
SE of systemic retinoids
teratogenic
Mucosal dryness, photosensitivity
Depression
DX, investigations and treatment
Small papule often between fingers with linear lesions on hands - VERY itchy, with itch worse at night.
Can spread to genitals in men or nipples in women.
Turns into generalised eczematous body rash as a late secondary hypersensitivity reaction.
Scabies
Skin scraping -> light microscopy
Treat w 5% permethrin cream + hot wash and dry of all clothes and beddings.
Treat ALL CONTACTS!
Treat accompanying eczema (topical steroids, emollients, oral antihistamines etc)
What is the order of frequency of skin cancers?
BCC - 67%
SCC - 31%
Melanoma - 2%
What disorders fall under the category characterised by keratinocyte dysplasia?
Actinic keratosis - 10% turn into SCC
SCC in situ (Bowen’s disease) - 5% turn into SCC
SCC
Do BCCs have precursor lesions?
No!
What are some atypical presentations of BCC to be aware of?
Superficial BCC - solitary red plaque (looks similar to rash) not responding to topical treatment, spreading radially
Infiltrative/sclerosing/morphoeic BCC - can present as a scar-like area of induration (scar tissue within BCC pulls in centrepidal pattern and can displace eyebrows/pull on lower eyelid)
MX of BCC
Nodular or infiltrating BCCs: wide local excision and biopsy
Superficial BCCs:
- excision
- serial curettage
- topical imiquimod
- photodynamic therapy
What is a benign junctional naevi?
Naevi appears during childhood
Located at epidermal side of dermal-epidermal junction
Macular, dark uniform colour, <1cm diameter
What is a benign compound naevi
Naves cells in epidermis AND dermis - papule or nodule
smooth or uniform border with uniform colour, <1cm
What is a benign intradermal naevi?
Naves cells are within the dermis only
Papule or nodule wiht even pale colour (skin-coloured/tan)
What are freckles due to?
How are lentigenes different?
Sun-induced increase in melanin, NOT melanocytes
Lentigenes are sun-induced pigmented macule (bigger) in middle aged people that do not change with time due to a few incr melanocytes.
What is a seborrhoeic keratose?
Skin lesion with a warty stuck-on appearance in older patients
Can get larger with time
May or may not be pigmented
What is a dysplastic naves?
Why do we care?
Atypical features clinically and atypically but NOT a malignant melanoma.
Generally >5mm, atypical pigment on dermoscopy, smudgy borders with 2+ colours but relatively symmetrical
<1/1000 risk of malignant transformation BUT possessing >1 is an independent risk factor for development of melanoma
Characteristics of nodular melanomas
Elevated, Firm, Growing
Often do NOT fulfil ABCDE criteria - do not LOOK like a melanoma
Rapid growth and early invasion
Lentigo Maligna (Melanoma) characteristics)
Gradually enlarging pigmented lesion usually on face SLOW evolution (years)
Superficial spreading melanoma characteristics
80% of melanomas
Follow ABCDE rules, evolving over weeks to months
Where are acral lentiginous melanomas usually found>
Soles or palms
