Dermatology Flashcards
How to describe a skin lesion?
Distribution
Configuration- linear, ergetoid, annular, discoid, clusters
Morphology- macular, papule, plaque, nodule, vesicle,crust,scabies
Classification of skin types?
Fitzpatrick I- VI
RFs of BCC?
Elderly
UV exposure
immunosuppressed
genetics
features of BCC?
shiny 'pearly surface' rolled edge telangiectasia- branch like capillaries surface ulceration slow growing, locally invasive, doesn't metastasise doesn't involve melanocytes
tx of BCC?
excision by Moh’s micrographic surgery
radiotherapy
RFs of a malignant melanoma?
UV light exposure fair skin red hair >100 naevi on body >5 atypical naevi FH
features of malignant melanoma?
looks like a suspicious mole, involves melanocytes A- asymmetrical B- Border irregularity C- colour irregularity D- diameter >6mm E- evolving
Types of malignant melanoma?
Superficial spreading (most common)
Nodular- sun-exposed areas, red or black lumps that bleed or ooze
Lentigo malinga- chronically sun-exposed skin
Melanoma of the nails
What is Breslow’s thickness?
Used for staging of malignant melanoma
TMN staging thicker= worse prognosis
TX of malignant melanoma?
excision
chemo, radiotherapy, immunological therapy for palliation
Common mets of malignant melanoma?
lung and brain
Features of SCC?
more keratotic and faster growing
keratotic appearance
high risk sites- lips and eyes
What is a precursor for SCC?
Actinic keratoses aka solar keratosis
due to chronic sun exposure
small, crusty of scaly lesions that are pink,red or brown in colour
Actinic keratoses are predominantly treated by cryotherapy.
What is SCC in situ?
Usually presents as one or more slowly enlarging erythematous scaly plaques, known as Bowen’s disease. Histologically, atypical keratinocytes are found throughout the epidermis without invasion through the basement membrane
Tx- surgically. Other treatments include cryotherapy, 5-fluorouracil cream, imiquimod cream or photodynamic therapy (PDT)
tx of SCC?
surgical excision with 4mm margins if lesion is <20mm
(6mm margins of >20mm)
Moh’s micrographic surgery
features of eczema?
patches in flexor surfaces (face and trunk in babies)
specific area in contact/irritant dermatitis
dry, red itchy skin
tx of eczema?
avoid triggers
frequent emollients
topical steroids for flare ups
topical immunomodulators e.g. tacrolimus, pimecrolimus
anti-histamines
antibiotics (flucloxacillin)/antivirals (acyclovir) for secondary infection
photoherapy
immunosuppresants- oral prednisolone, azathioprine, ciclosporin
Complications of eczema
2nd bacterial infection- crusted weepy lesions
2nd viral infection- molluscum contagiosum, viral warts, eczema herpeticum
What is psoriasis?
chronic inflammatory skin condition due to hyperproliferation of keratinocytes and inflammatory cell infiltration
types of psoriasis?
chronic plaque psoriasis
guttate (raindrop lesions, children)
pustular (palmar-plantar)
erythrodermic (total body redness)
precipitating factors for psoriasis?
trauma- koebner phenomenon infection e.g. tonsillitis stress alcohol drugs- beta blockers, lithium, NSAIDs, ACEi, TNFi, anti-malarials
presentation of psoriasis?
well-demarcated erythematous scaly plaques
extensor surfaces
auspitz sign- removal of scales causes bleeding
nail changes- pitting, onycholysis
psoriatic arthropathy
tx of psoriasis?
avoid precipitating factors, emollients
1st line- vit D analogues (calcitriol) and topical corticosteroids for 4 weeks
topical retinoids
keratolytics
phototherapy
methotrexate, oral retinoids, ciclosporin, mycophenolate
Biological agents- infliximab, etanercept, efalizumab
Causes of guttate psoriasis?
strep throat (group A strep)
features of guttate psoriasis?
raindrop shaped plaques, silver scale, usually on trunk
Ix of guttate psoriasis?
throat swab for anti-streptolysin O titre
Tx of guttate psoriasis?
most self-resolve within 2-3 months
topical agents as per psoriasis
UVB phototherapy
Tonsillectomy if recurrent episodes
Pathology of acne vulgaris?
obstruction of pilosebaceous follicles with keratin plugs, causing comedomes, inflammation and pustules
Organism= Propionibacterium acnes
Features of acne vulgaris?
comedones (dilated sebaceous follicles) papules pustules nodules cysts scarring
Tx of acne vulgaris?
- simple topical therapy: topical retinoids (tretinoin)- vit A analogues or benzyl peroxide
- Topical combination- tetracycline and topical therapy above
- Oral Abx- tetracycline, oxytetracycline
- Oral isotretinoin (roaccutane)
SEs of roaccutane?
dry skin, depression, LFT derangement, increase in serum triglycerides, teratogenic, hair thinning, nose bleeds, IIH, photosensitivity
Features of acne rosacea?
flushing of nose, cheeks and forehead
telangiectasia
persistent erythema with papules and pustules
rhinophyma
ocular involvement- blepharitis, keratitis, conjunctivitis
exacerbated by sunlight
tx of acne rosacea?
topical metronidazole
systemic antibiotics (oxytetracycline)- severe disease
suncream
laser treatment
What is lichen planus?
Lichen planus is a chronic inflammatory skin condition affecting the skin and mucosal surfaces
Causes of lichen planus?
quinine, gold, thiazides
features of lichen planus?
All the P's: purple pruritic papular polygonal most common on palms, soles and genitals wickham's striae- white lace pattern on the surface oral involvement in 50% nail signs- thinning, longitudinal ridging
tx of lichen planus?
1st line- clobetasone butyrate
mouthwash for oral disease
systemic steroids for extensive disease
Where are venous ulcers and what causes them?
medial malleolus
due to venous insufficiency
tx of venous ulcers?
compression bandages
refer to vascular surgery
features of arterial ulcers?
deep, punched out, necrotic lesions painful, pressure sites shiny skin increased CRT, poor peripheral pulses hypoperfusion RFs for arterial disease
Ix of arterial ulcers?
<0.9 ABPI
don’t use compression bandages as could cause critical limb ischaemia
tx of arterial ulcers?
revascularisation surgery
exercise
modify CV risk factors
RFs of neuropathic ulcers
diabetes, peripheral neuropathy
features of neuropathic ulcers
commonly over plantar surface of metatarsal head and plantar surface of hallux
pressure sites
punched out/necrotic lesions
Tx of neuropathic ulcers
education on diabetic foot health
cushioned shoes
what is bullous phemigold?
autoimmune, sub-epidermal blistering of the skin
RF for bullous phemigold
elderly
features of bullous phemigold
itchy,tense blisters
typically around flexures
usually heal without scarring
mouth spared
what is seen on biopsy in bullous phemigold?
IgG and c3
tx for bullous phemigold?
oral corticosteroids
What is vitiligo?
autoimmune loss of melanocytes leading to depigmentation
associations with vitiligo?
T1DM addisons disease pernicious anaemia autoimmune thyroid diseas alopecia
tx for vitiligo?
sunscreen
topical corticosteroids- may reverse if applied early enough
tacrolimus and phototherapy
what are associations with alopecia areata?
thyroid disease, diabetes, pernicious anaemia
tx for alopecia?
topical steroids topcai lminoxidil phototherapy contact immunotherapy wigs
what is a seborrhoeic wart?
benign, epidermal, affects elderly
stuck-on appearance
keratotic plugs may be seen on the surface
reassure they are benign but can remove if they are irritating
what causes irritant contact dermatitis?
frictional injury, soaps, detergents, mild acids and alkalis
What causes allergic contact dermatitis?
Type IV hypersensitivity reaction
allergen is usually previously tolerated
can magnify in various ways- erythema, vesicles or bullae blisters, oedema, dryness, cracks
tx of contact dermatitis?
avoid precipitant topical corticosteroids emolliants systemic corticosteroids phototherapy immunosuppressive agents e.g. methotrexate
what is molluscum contagiosum?
caused by MC virus
transmitted by close personal contact
self-limiting, lasts <18 months
features of molluscum contagiosum?
pinkish/pearly white papules central umbilication up to 5mm diameter lesions appear in clusters spares palms and soles can be on genitalia due to sexual contact
tx of molluscum contagiosum?
squeeze after a bath
cryotherapy
steroid if itchy
antibiotics if crusted/ looks infected
What causes scabies?
tiny mites called sarcopetes scabeii
eggs laid in skin
think if intense itchy rash
features of scabies?
widespread pruritic
linear burrows- sides of fingers
excoriations
scalp and face can be affected in infants
tx of scabies?
permethrin 5%
malthion 0.5%
treat whole family on same day
clean all bedding on 1st day of treatment
What are cellulitis and erysipelas?
spreading bacterial infection of the skin
cellulitis= deep cutaneous tissue
erysipelas= acute superficial form affecting dermis and upper subcut tissue
causes of cellulitis?
staph aureus
strep pyogenes
RFs for cellulitis?
immunosuppression
wounds
leg ulcers
minor skin injury
features of cellulitis?
commonly occurs on the shins
erythema, pain, swelling
there may be some associated systemic upset such as fever
Tx of cellulitis?
The BNF recommends flucloxacillin as first-line treatment for mild/moderate cellulitis. Clarithromycin, erythromycin (in pregnancy) or doxycyline is recommended in patients allergic to penicillin.
NICE recommend that patients severe cellulitis should be offered co-amoxiclav, cefuroxime, clindamycin or ceftriaxone
IV of severe or oral if mild-moderate (Eron classification)
what is orbital cellulitis?
Orbital cellulitis is the result of an infection affecting the fat and muscles posterior to the orbital septum, within the orbit but not involving the globe. It is usually caused by a spreading upper respiratory tract infection from the sinuses
RFs for orbital cellulitis?
Childhood
Previous sinus infection
Lack of Haemophilus influenzae type b (Hib) vaccination
Recent eyelid infection/ insect bite on eyelid (Peri-orbital cellulitis)
Ear or facial infection
mx of orbital cellulitis?
admission to hospital for IV antibiotics
what are common causes of fungal skin infections?
dermatophytes (tinea,ringworm)
yeasts (candidiasis, malassezia)
moulds (aspergillus)
name one topical antifungal drug and one oral?
topical- terbinafine cream
oral- itraconazole, terbinafine
what is erythroderma?
a term used when more than 95% of the skin is involved in a rash of any kind.
RED SKIN, inflamed, oedematous
systemically unwell with lymphadenopathy and malaise
derm emergency
causes of erythroderma?
prev skin disease
lymphoma
drugs (sulphonamides, sulphonylureas, penicillin)
tx of erythroderma
treat underlying cause, emollients and wet wraps
topical steroids
complications of erythroderma?
secondary infection fluid loss electrolyte imbalance hypothermia cardiac failure capillary leakage syndrome
what is the pathology of urticaria?
mast cells causing histamine release and inflammatory mediator release that cause increased permeability of capillaries
causes of urticaria?
idiopathic drugs- penicillin, contrast media, NSAIDs, morphine, ACEi foods contrast e.g. latex viral or parasitic infections autoimmune issues
features of urticaria?
Characterised by weals (hives) or angioedema
A wheal is a superficial skin-coloured or pale skin swelling, usually surrounded by erythema that lasts anything from a few minutes to 24 hours. Usually very itchy, it may have a burning sensation.
Angioedema is deeper swelling within the skin or mucous membranes and can be skin-coloured or red. It resolves within 72 hours. Angioedema may be itchy or painful but is often asymptomatic
what can urticaria progress to?
anaphylaxis-bronchospasm, hypotension, facial and laryngeal oedema
Ix for urticaria?
Skin prick tests and RAST or CAP fluoroimmunoassay may be requested if a drug or food allergy is suspected in acute urticaria
Bloods and CRP
Tx of urticaria?
antihistamines for urticaria
corticosteroids for urticaria and angioedema
adrenaline, corticosteroids and antihistamines for anaphylaxis
what are the doses of meds in anaphylaxis?
adrenaline- 500mcg = 0.5mg IM (0.5mls of 1 in 1000 adrenaline IM)
hydrocortisone- 200mg
chlorphenamine- 10mg
what is the cause of eczema herpeticum?
HSV
a disseminated viral infection characterised by fever and clusters of itchy blisters or punched-out erosions. It is most often seen as a complication of atopic dermatitis/eczema.
features of eczema herpeticum?
extensive crusted papules, blisters and erosions
systemically unwell with fever and erosions
Tx of eczema herpeticum?
aciclovir IV
antibiotics if secondary bacterial infection
complications of eczema herpeticum?
encephalitis, herpes hepatitis, DIC and death
what is erythema multiforme?
inflammatory, self-limiting red lesions across body
‘target lesions’
mucosal involvement limited to one mucosal surface
what is the dose of adrenaline in a cardiac arrest?
adrenaline- 10mls of 1 in 10000 IV is the dose in cardiac arrest
what are the causes of erythema multiforme?
HSV, infections, medications (e.g. phenotoin, penicillin, NSAIDS)
how can erythema multiforme progress to steven-johnson syndrome?
mucocutaneous necrosis with at least 2 mucosal sites involved
skin involvement may be limited or extensive
associated more with drugs
what does steven Johnson syndrome progress to?
toxic epidermal necrosis
What is toxic epidermal necrosis?
full thickness epidermal necrosis with subepidermal involvement
accompanied by systemic toxicity
usually drug induced- phenytoin, sulphonamides, allopurinol, penicillins, NSAIDs, carbamazepine
What are the risks of toxic epidermal necrosis?
sepsis, multi-system organ failure
mx of toxic epidermal necrosis?
early recognition and call for help
full supportive care to maintain haemodynamic equilibrium
what is necrotising fasciitis?
rapidly spreading infection of the deep fascia with secondary tissue necrosis
what is the cause of nec fasciitis?
group A haemolytic streptococcus
RFs for necrotising fasciitis?
abdominal surgery
medical co-morbidities e.g. DM,malignancy
features of necrotising fasciitis?
severe pain erythematous, bleeding necrotic skin systemically unwell with fever and tachycardia presence of crepitus XR may show soft tissue gas
Tx of necrotising fasciitis?
Surgical debridement asap
IV Abx
what is dermatitis herpetiformis?
autoimmune blistering skin disorder associated with coeliac disease
what is a cause of dermatitis herpetiformis?
deposition of IgA in the dermis
features of dermatitis herpetiformis?
itchy, vesicular rash on the extensor surfaces e.g elbows, knees, buttocks
How to diagnose dermatitis herpetiformis?
skin biopsy- direct immunofluorescence shows deposition of IgA in a granular patters in the upper dermis
Tx of dermatitis herpetiformis?
gluten-free diet
dapsone
What are common non-skin causes of pruritis?
- liver disease- Hx of alcohol excess, stigmata of chronic liver disease (spider naevi, bruising, palmar erythema, gynaecomastia)
- iron deficiency anaemia- pallor, koilonychia, atrophic glossitis, post-cricoid webs, angular stomatitis
- Polycythaemia- esp after a warm bath
- CKD-lethargy and pallor, weight gain and oedema, hypertension
- lymphoma- B symptoms
What is seborrhoeic dermatitis?
inflammatory reaction to Malassezia furfur that causes dandruff and eczematous lesions
tx of seborrhoeic dermatitis?
OTC preparations containing zinc pyrithione and tar
ketoconazole
selenium sulphide and topical corticosteroid
what is the immediate management of a burns patient?
airway, breathing, circulation
burns caused by heat: remove the person from the source. Within 20 minutes of the injury irrigate the burn with cool (not iced) water for between 10 and 30 minutes. Cover the burn using cling film, layered, rather than wrapped around a limb
electrical burns: switch off power supply, remove the person from the source
chemical burns: brush any powder off then irrigate with water. Attempts to neutralise the chemical are not recommended
How to measure the extent of burns?
Wallace’s Rule of Nines: head + neck = 9%, each arm = 9%, each anterior part of leg = 9%, each posterior part of leg = 9%, anterior chest = 9%, posterior chest = 9%, anterior abdomen = 9%, posterior abdomen = 9%
What are the different depths of burns?
Superficial epidermal
Partial thickness (superficial dermal)
Partial thickness (deep dermal)
Full thickness
How does a superficial epidermal burn appear?
red and painful
How does a Partial thickness (superficial dermal) appear?
pale pink, painful, blistered
How does a Partial thickness (deep dermal) appear?
typically white but may have patches of non-blanching erythema
reduced sensation
How does a full thickness burn appear?
white/brown/black in colour, no blisters, no pain
What is erythema nodosum?
inflammation of sub cut fat
What are the causes of erythema nodosum?
NO- idiopathic D- drugs e.g. penicillin, sulphonamides O- oral contraceptive/ pregnancy S- sarcoidosis/ TB U- UC/crohn's/Bechet's disease M- microbiology (streptococcus, mycoplasma, EBV and more)
What are the features of hereditary haemorrhagic telangiectasia?
> 2- diagnosis
- epistaxis
- telangiectases- lips, oral cavity, fingers, nose
- visceral lesions e.g. GI, pulmonary, hepatic, cerebral, spinal
mx of impetigo?
topical fusidic acid
oral flucloxacillin or erythromycin
mx of animal or human bite?
co-amoxiclav
mx of mastitis?
flucloxacillin
mc of erysipelas
phenoxymethylpenicillin
