Dermatology Flashcards
1
Q
Acanthosis Nigricans
A
Symmetrical, brown, velvety plaques found on the neck, axilla and groin
Causes:
- T2DM
- GI cancer
- obesity
- PCOS
- acromegaly
- Cushing’s disease
- hypothyroidism
- familial
- Prader-Willi
- COCP
- nicotinic acid
Insulin resistance -> hyperinsulinaemia -> stimulation of keratinocytes and dermal fibroblast proliferation via interaction with IGFR1
2
Q
Acne Vulgaris
A
Obstruction of the pilosebaceous follicles with keratin plugs which results in comedones, inflammation and pustules
Mild: open and closed comedones with or without sparse inflammatory lesions
Moderate: widespread non-inflammatory lesions and numerous papules and pustules
Severe: extensive inflammatory lesions which may include nodules, pitting and scarring
3
Q
Treatment of Mild to Moderate Acne
A
12 week course of topical combination therapy:
- topical adapalene with topical benzoyl peroxide
- tropical tretinoin with topical clindamycin
- topical benzoyl peroxide with topical clindamycin
Topical benzoyl peroxide may be used as monotherapy if these options are contraindicated or the person wishes to avoid using a topical retinoid or antibiotic
4
Q
Treatment of Moderate to Severe Acne
A
12 weeks of:
- a fixed combination of topical adapalene with topical benzoyl peroxide
- a fixed combination of topical treitnoin with topical clindamycin
- a fixed combination of topical adapalene with topical benzoyl peroxide + either oral lymecycline or oral doxycycline
- a topical azelaic acid + oral lymecycline/doxycycline
*oral isotretinoin can be used only under specialist supervision (contraindicated in pregnancy)
5
Q
Oral Antibiotics in Acne Treatment
A
- tetracyclines should be avoided in pregnant or breastfeeding women and children younger than 12
- erythromycin may be used in pregnancy
- minocycline is less appropriate due to risk of irreversible pigmentation
- only continue antibiotics (topical or oral) >6 months in exceptional circumstances
- a topical retinoid or benzoyl peroxide should always be co-prescribed with oral antibiotics to reduce the risk of antibiotic resistance
- gram negative folliculitis may occur as a complication of long-term antibiotic use - high dose oral trimethoprim is effective
6
Q
COCP in Acne
A
- can be used in combination with topical agents
- dianette (co-cyprindiol) is sometimes used as it has anti-androgen properties however there is increased risk of VTE therefore is 2nd line and can only be used for 3 months
7
Q
NICE referral Criteria for Acne
A
- patients with acne conglobate - rare and severe form of acne found mostly in men that presents with extensive inflammatory papules, suppurative nodules that may coalesce to form sinuses and cysts on the trunk
- patients with nodulo-cystic acne
Consider in:
- mild to moderate that has not responded to 2 courses of treatment
- moderate to severe that has not responded to previous treatment including oral antibiotic
- acne with scarring
- acne with persistent pigmentary changes
- acne is causing or contributing to persistent psychological distress/MH disorder
8
Q
Actinic Keratoses
A
- common premalignant skin lesion that develops as a consequence of chronic sun exposure
- features:
- small, crusty, scaly lesions
- pink, red, brown or the same colour as the skin
- typically on sun-exposed areas
- multiple lesions
9
Q
Management of Actinic Keratoses
A
- prevention of further risk
- fluorouracil cream: typically a 2-3 week course - the skin will become red and inflamed
- topical diclofenac - moderate efficacy but much fewer side effects
- topical immiquimod
- cryotherapy
- curettage and cautery
10
Q
Scarring Alopecia
A
- destruction of the hair follicle
- trauma, burns
- radiotherapy
- lichen planus
- discoid lupus
- tinea capitis
11
Q
Non-scarring Alopecia
A
- preservation of hair follicle
- male-pattern baldness
- drugs: cytotoxic drugs, carbimazole, heparin, oral contraceptive pill, colchicine
- nutritional: iron and zinc deficiency
- autoimmune: alopecia areata
- telogen effluvium:
- hair loss following stressful periods
- trichotillomania
12
Q
Alopecia Areata
A
- presumed autoimmune condition causing localised, well demarcated patches of hair loss
- at the edge of the hair loss, there may be small, broken ‘exclamation mark’ hairs
- hair will regrow in 50% of patients by 1 year and in 80-90% eventually
- other treatment options:
- topical or intralesional corticosteroids
- topical minoxidil
- phototherapy
- dithranol
- contact immunotherapy
- wigs
13
Q
Antihistamines
A
- H1 inhibitors
- treatment of allergic rhinitis and urticaria
- sedating ones also have antimuscarinic properties (urinary retention, dry mouth)
14
Q
Basal Cell Carcinoma
A
- “rodent ulcers” - slow growth and local invasion
- metastases are extremely rare
- sun-exposed sites
- initially a pearly, flesh-coloured papule with telangiectasia
- may later ulcerate leaving a central crater
- requires routine referral
- surgical removal
- curettage
- cryotherapy
- topical cream
- radiotherapy
15
Q
Bullous Pemphigoid
A
- autoimmune condition causing sub-epidermal blistering of the skin - secondary to development of antibodies against hemidesmosomal proteins BP180 and BP230
- more common in elderly patients
- itchy, tense blisters typically around flexures
- heal without scarring
- no mucosal involvement
- immunofluorescence shows IgG and C3 at the dermoepidermal junction
- refer to dermatologist for biopsy and confirmation
- oral corticosteroids
- topical corticosteroids, immunosuppressants and antibiotics can be used
16
Q
Immediate Management of Burns
A
- airway, breathing, circulation
- heat –> remove patient from source, within 20 minutes of the injury irrigate the burn with cool 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 person from source
- chemical burns: brush any powder off then irrigate with water, attempts to neutralise the chemical are not recommended
17
Q
Assessing the Extent of the Burn
A
- Wallace’s Rule of Nines: head + neck 9%, each arm 9%, each anterior part of leg 9%, anterior chest 9%, posterior chest 9%, anterior abdomen 9%, posterior abdomen 9%
- Lund and Browder chart - the most accurate method
- the palmar surface is roughly equivalent to 1% TBSA (not accurate > 15%)
18
Q
Depth of Burn
A
- superficial epidermal (1st degree) - red, painful, dry, no blisters
- partial thickness/superficial dermal (2nd degree) - pale pink, painful, blistered, slow capillary refill
- partial thickness/deep dermal (2nd degree) - typically white but may have patches of non-blanching erythema. Reduced sensation, painful to deep pressure
- full thickness (3rd degree) - white/brown/black, no blisters, no pain
19
Q
Burns Referral to Secondary Care
A
- all deep dermal and full-thickness burns
- superficial dermal burns of more than 3% TBSA or more than 2% TBSA in children
- superficial dermal burns involving the face, hands, feet, perineum, genitalia, or any flexure, or circumferential burns of the limbs, torso or neck
- any inhalation injury
- any electrical or chemical burn
- suspicion of non-accidental injury
20
Q
Pathophysiology of Severe Burns
A
- local response with progressive tissue loss and release of inflammatory cytokines
- systemically, there are cardiovascular effects resulting from fluid loss and sequestration of fluid into the third space
- marked catabolic response
- immunosuppression is common with large burns and bacterial translocation from the gut lumen is a recognised event
- sepsis is a common cause of death
21
Q
Management of Severe Burns
A
- smoke inhalation can result in airway oedema
- early intubation should be considered
- IVF for children burns > 10% TBSA/adults > 15%
- Parklands formula: volume = TBSA of burn % x weight x 4 - half in first 8 hours
- catheter
- analgesia
- ?transfer to burns unit
- no evidence for use of anti-microbial prophylaxis or topical antibiotics
22
Q
Escharotomies
A
- indicated in circumferential thickness burns to the torso or limbs
- careful division of the encasing band of burn tissue will improve ventilation or relieve compartment syndrome and oedema
23
Q
Extensive Burns Pathology
A
- haemolysis due to damage of erythrocytes by heat and microangiopathy
- loss of capillary membrane integrity causing plasma leakage into interstitial space
- extravasation of fluids from the burn site causing hypovolaemic shock
- protein loss
- secondary infection
- ARDS
- risk of Curlings ulcer
- compartment syndrome
24
Q
Chondrodermatitis Nodularis Helicis
A
- development of benign painful nodule on ear
- persistent pressure on the ear (secondary to sleep, headsets), trauma or cold
- more common in men and increasing age
- management:
- reducing pressure on ear
- cryotherapy, steroid/collagen injection
- surgical treatment (high recurrence rate)
25
Chronic Plaque Psoriasis
- 80% of psoriasis
- erythematous plaques covered with a silvery-white scale
- typically on extensor surfaces + scalp, trunk, buttocks and periumbilical area
- clear delineation between normal and affected skin
- plaques typically range from 1-10cm
- Auspitz's sign - red membrane with pinpoint bleeding points after scale removal
26
Irritant Contact Dermatitis
- common
- non-allergic reaction due to weak acids or alkalis
- often seen on hands
- erythema is typical, crusting and vesicles are rare
27
Allergic Contact Dermatitis
- type IV hypersensitivity reaction
- uncommon
- often seen on the head after hair-dye
- acute, weeping eczema
- topical treatment with a potent steroid
28
Dermatitis Herpetiformis
- autoimmune blistering skin disorder associated with coeliac disease
- caused by deposition of IgA in the dermis
- itchy, vesicular skin lesions on the extensor surfaces
- diagnosis: skin biopsy: direct immunofluorescence shows deposition of IgA in a granular pattern in the upper dermis
- management: gluten free diet, dapsone
29
Dermatofibroma
- benign fibrous skin lesions
- abnormal growth of the dermal dendritic histiocyte cells, often following a precipitating injury
- common on arms and legs
- solitary firm papule or nodule
- typically around 5-10mm in size
- overlying skin dimples on pinching the lesions
30
Eczema Herpeticum
- severe primary infection by HSV 1 or 2
- commonly seen in children with atopic eczema and presents as a rapidly progressing painful rash
- monomorphic punched out erosions (circular, depressed, ulcerated lesions), usually 1-3mm in diameter
- IV aciclovir (potentially life threatening)
31
Topical Steroids
- mild: hydrocortisone 0.5-2.5%
- moderate: betamethasone valerate 0.025% (betnovate RD), clobetasone butyrate 0.05% (eumovate)
- potent: fluticasone propionate 0.05% (cutivate), betamethasone valerate 0.1% (betnovate)
- clobetasol propionate 0.05% (dermovate)
32
Erythema Ab Igne
- caused by overexposure to infrared radiation
- reticulated, erythematous patches with hyperpigmentation and telangiectasis
- "elderly woman who always sits next to a open fire"
- can cause squamous cell skin cancer
33
Erythema Multiforme
- hypersensitivity reaction caused by infections
- target lesions
- seen on back of the hands/feet before spreading to torso
- pruritus is occasionally seen and is mild
- causes:
- viruses: HSV, Orf
- idiopathic
- bacterial: mycoplasma, streptococcus
- drugs: penicillin, sulphonamides, carbamazepine, allopurinol, NSAIDs, OCP, nevirapine
- connective tissue disease: SLE
- sarcoidosis
- malignancy
(major --> mucosal involvement --> skin disease of sheep and goats caused by parapox virus)
34
Erythema Nodosum
- inflammation of subcutaneous fat
- typically causes tender, erythematous, nodular lesions
- usually over skins
- resolves in 6 weeks
- no scarring
- infection: streptococci, TB, brucellosis
- systemic disease: sarcoidosis, IBD, Behcet's
- malignancy/lymphoma
- drugs: penicillin, sulphonamides, COCP
- pregnancy
35
Treatment of Fungal Nail Infections
- if limited involvement - topical amorolfine 5% 6-12 months
- if more extensive involvement due to dermatophyte - oral terbinafine for 6 weeks - 6 months
- if more extensive involvement due to Candida - oral itraconazole - pulsed weekly therapy
36
Fungal Nail Infections
- dermatophytes (90%) - mainly trichophyton rubrum
- yeasts (5-10%) - candida
- non-dermatophyte moulds
- risk factors: aging, diabetes mellitus, psoriasis, repeated nail trauma
- thickened, rough, opaque nails
- differentials: psoriasis, lichen planus, yellow nail syndrome
- investigations: nail clippings sent for microscopy and culture
37
Guttate Psiorasis
- more common in children and adolescents
- precipitated by a streptococcal infection 2-4 weeks
- tear drop papules on the trunk and limbs
- pink, scaly patches
- most cases resolve in 2-3 months
- no evidence for antibiotics
- topical agents as per psoriasis
- UVB phototherapy
- tonsillectomy if recurrent
38
Hereditary Haemorrhagic Telangiectasia
- autosomal dominant condition characterised by multiple telangiectasia over skin and mucous membranes
- 20% no prior family history
- 4 criteria:
- epistaxis
- telangiectasia
- visceral lesions: GI, AVM (pulmonary, hepatic, cerebral, spinal)
- family history
39
Hirsutism
Hirsutism = androgen dependent hair growth in women
Causes:
- PCOS
- Cushing's syndrome
- congenital adrenal hyperplasia
- androgen therapy
- obesity
- adrenal tumour
- androgen secreting ovarian tumour
- drugs: phenytoin, corticosteroids
Ferriman-Gallwey scoring system
Management:
- weight loss
- cosmetic techniques
- COCP
- topical eflornithine for facial
40
Hypertrichosis
Androgen dependent hair growth
Causes:
- minoxidil, ciclosporin, diazoxide
- congenital hypertrichosis lanuginosa, congenital hypertrichosis terminalis
- porphyria cutanea tarda
- anorexia nervosa
41
Hyperhidrosis
Excessive production of sweat
Topical aluminium chloride preparations are first line - skin irritation
iontophoresis: palmar, plantar and axillary hyperhidrosis
botulinum toxin: axillary symptoms
surgery: endoscopic transthoracic sympathectomy (risk of compensatory sweating)
42
Impetigo
Staphylococcus aureus or Streptococcus pyogenes
Tends to occur on face, flexures and limbs
Spread is by direct contact with discharge from scabs - invades skin through minor abrasions
Incubation period 4-10 days
Golden, crusted skin lesions
Management:
- limited local disease: hydrogen peroxide 1%, topical fusidic acid, topical mupirocin
- extensive disease: oral flucloxacillin or erythromycin
Children should be excluded from school until lesions are crusted and healed or 48 hours after commencing antibiotics
42
Keloid Scars
Tumour-like lesions that arise from connective tissue of a scar and extend beyond
More common in people with dark skin
More common in young people
Common sites: sternum, shoulder, neck, face, extensor surface of limbs, trunk
Keloid scars are less likely if incisions made along relaxed skin tension lines
Early keloids may be treated with intra-lesional steroids (triamcinolone)
Excision is sometimes required but can create further keloid scarring
43
Keratoacanthoma
Benign epithelial tumour
More common with advancing age and rare in young people
Looks like a volcano or crater - initially smooth dome-shaped papule which rapidly grows to become a crater centrally filled with keratin
Spontaneous regression within 3 months is common, often resulting in a scar
Lesions should be urgently removed as difficult to clinically exclude SCC
44
Leukoplakia
Premalignant condition which presents as white, hard spots on the mucous membranes of the mouth
More common in smokers
Diagnosis of exclusion
Biopsies performed to exclude alternative diagnoses such as SCC and regular f/up required
1% malignant transformation to SCC
45
Lichen Planus
- Itchy, papular rash most common on the palms, soles. genitalia and flexor surfaces of arms
- rash often polygonal with white lines pattern on the surface (Wickham's striae)
- Koebner phenomenon may be seen (new lesion at site of trauma)
- oral involvement in 50%
- thinning of nail plate, longitudinal ridging
- causes: gold, quinine, thiazides
- potent topical steroids
- benzydamine mouthwash or spray
- may require oral steroids or immunosuppression
46
Lichen Sclerosus
Inflammatory condition that affects the genitalia and is more common in elderly females
Leads to atrophy of the epidermis with white plaque formation
Features:
- white patches
- itch
- pain during intercourse/urination
Management: topical steroids and emollients
Increased risk of vulval cancer
47
Livedo Reticularis
Purplish, non-blanching, reticulated rash caused by obstruction of the capillaries resulting in swollen venules
Causes:
- idiopathic
- polyarteritis nodosa
- SLE
- cryoglobulinemia
- antiphospholipid syndrome
- Ehlers-Danlos
- homocystinuria
48
Malignant Melanoma
4 main subtypes: superficial spreading, nodular, lentigo maligna and acral lentiginous
Main diagnostic features:
- change in size, shape or colour
Secondary features:
- diameter >7mm, inflammation, oozing or bleeding, altered sensation
Treatment:
- suspicious lesions --> excision biopsy
- further treatment such as sentinel lymph node mapping, isolated limb perfusion and block dissection of regional lymph node groups as needed
49
Superficial Spreading Melanoma
70% of cases
Arms, legs, back and chest
Young people
A growing mole with diagnostic features
49
Nodular Melanoma
Second commonest
Sun exposed skin
Middle-aged people
Red or black lump which bleeds or oozes
49
Lentigo Maligna Melanoma
Less common
Chronically sun-exposed skin
Older people
A growing mole with diagnostic features
50
Acral Lentiginous Melanoma
Rare
Nails, palms or soles
People with darker skin pigmentation
Subungual pigmentation (Hutchinson's sign) or on palms or feet
51
Malignant Melanoma: Prognostic Factors (5 year survival)
Breslow Thickness:
- < 0.75mm - 95-100%
- 0.76-1.50mm - 80-96%
- 1.51-4mm - 60-75%
- > 4mm - 50%
52
Milia
- small, benign, keratin- filled cysts that typically appear around the face
- appear at any age but are more common in newborns
53
Molluscum Contagiosum
Transmission by close personal contact or via formites (shared towels/flannels)
Occurs in children (1-4 years)
Presents with pinkish/pearly white papules with central umbilication up to 5mm in diameter
Lesions cluster anywhere in the body (except palms and soles)
Self-limiting - resolves within 18 months
Treatment is not usually recommended
- can squeeze lesions
- cryotherapy
- itching - emollient and a mild topical corticosteroid
- infected - topical antibiotics
Referral:
- HIV positive
- eyelid-margin/ocular lesion and associated red eye
- anogenital lesions - screen for STI
54
Mycosis Fungoides
Rare form of T cell lymphoma
Itchy, red patches which are typically confused with eczema or psoriasis
Lesions tend to be of different colours
55
Pellagra
Caused by nicotinic acid (niacin) deficiency
3 D's - dermatitis, diarrhoea, dementia
May occur as a consequence of isoniazid therapy - more common in alcoholics
Brown, scaly rash on sun-exposed sites (Casal's necklace)
Depression
Death if not treated
56
Pemphigus vulgaris
Autoimmune disease caused by antibodies directed against desmoglein 3
More common in Ashkenazi Jewish population
Mucosal ulceration is common - oral involvement in 50-70%
Skin blistering - flaccid, easy to rupture vesicles and bullae - painful not itchy
Acantholysis on biopsy
Steroids are first line
Immunosuppressants
56
