Dermatology Flashcards

1
Q

What is a vesicle?

A

Fluid-filled blister less than 0.5 cm in diameter

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2
Q

What is a bulla?

A

Fluid-filled blister more than 0.5 cm in diameter

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3
Q

What is a skin fissure?

A

Deep crack/crevice into skin

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4
Q

What is a macule?

A

Flat pigmented lesion less than 1 cm in diameter

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5
Q

What is a patch?

A

Flat pigmented lesion more than 1 cm in diamter

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6
Q

What is a papule?

A

Raised lesion less than 0.5 cm in diameter

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7
Q

What is a nodule?

A

Raised lesion more than 0.5 cm in diameter

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8
Q

What is a pustule?

A

Pus-filled lesion

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9
Q

What is a plaque?

A

Raised lesion more than 1 cm in diameter

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10
Q

What is lichenification?

A

Thickened skin

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11
Q

What is purpura?

A

Purple pigmentation that does not blanche

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12
Q

What is petechiae?

A

1-2 mm of purpura

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13
Q

What is erythema?

A

Red pigmentation that does blanche

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14
Q

What is an erosion?

A

Superficial break in epidermis

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15
Q

What is an ulcer?

A

Deep break in epidermis and dermis

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16
Q

What is a wheal?

A

Compressible dermal swelling

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17
Q

List skin manifestations of diabetes

A
Flexural candidiasis
Folliculitis, infection
Necrobiosis lipoidica
Acanthosis nigricans
Ulcers
Xanthomata
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18
Q

What is necrobiosis lipoidica?

A

Waxy, shiny red-brown plaques with atrophic yellow lesions on shins

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19
Q

What is acanthosis nigricans?

A

Velvety thickening of skin, usually in the axillae

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20
Q

What is the main skin manifestation of Coeliac disease?

A

Dermatitis herpetiformis

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21
Q

List skin manifestations of inflammatory bowel disease

A

Erythema nodosum

Pyoderma gangrenosum

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22
Q

What is erythema nodosum?

A

Tender, ill-defined nodules usually found on shins

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23
Q

What is pyoderma gangrenosum?

A

Recurring nodulo-pustular ulcers that have a red-blue necrotic edge

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24
Q

List skin manifestations of systemic lupus erythematosus

A

Butterfly rash
Photosensitivity
Alopecia

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25
What is the main skin manifestation of herpes simplex infection?
Erythema multiforme
26
List skin manifestations of vasculitis
Purpura (may be palpable) Nodules Livedo reticularis
27
What is livedo reticularis?
Mottled red-blue lesions that don't blanche | Usually triggered in the cold
28
List skin manifestations of dermatomyositis
Heliotrope rash Gottron's papules Scaly red plaques over neck (V-sign) Periungual redness
29
List aetiology/risk factors for atopic dermatitis
Genetic mutation in filaggrin gene Overactive TH2 cells results in more circulating IL-4, IL-5, IgE Infection (Staph aureus) Exacerbators (dust, temperature, allergies)
30
List clinical features of atopic dermatitis
``` Itchy, dry skin Flexural scale and erythema Weepy vesicles Lichenification Hyperlinear pals Eczema herpeticum (HSV infection) ```
31
What investigations would you do for atopic dermatitis?
Serum IgE
32
What is the clinical criteria for diagnosing childhood eczema?
``` Itch + 3 of: Flexural rash Onset before 2 years of age History of atopy Dry skin ```
33
Outline treatment options for atopic dermatitis
Allergen/trigger avoidance Emollients (Epaderm, Diprobase) Topical steroid (hydrocortisone, clobetasone, betametasone, mometasone, clobetasol) Immunomodulator (tacrolimus, ciclosporin) Antibiotic if infection Antihistamine Paste bandaging Phototherapy/systemic therapy if non-responsive
34
Ointments are more effective than emollients for dry skin. True/False?
True
35
What is contact allergic dermatitis?
Type IV hypersensitivity skin reaction to environmental allergens
36
List aetiology/risk factors for contact allergic dermatitis
Nickel Chemicals, creams Rubber Occupational substances
37
List clinical features of contact allergic dermatitis
Localised rash with cut-off patern Itch Rhinitis Wheal
38
What is contact irritant dermatitis?
Non-specific skin reaction to environmental substances
39
List aetiology/risk factors for contact irritant dermatitis
``` Soap, detergents Oil Bleach Trauma Occupational substances ```
40
List clinical features of contact irritant dermatitis
Localised rash/redness Weeping Dry fissures Usually hands affected
41
How would you differentiate between contact allergic and irritant dermatitis?
Patch testing to check for allergic trigger
42
Outline treatment for contact dermatitis
Avoid allergen/trigger | Topical steroid
43
What is stasis dermatitis?
Chronic venous insufficiency/hypertension causes blood pooling and skin disease
44
List aetiology/risk factors for stasis dermatitis
Obesity Varicose veins History of DVT
45
List clinical features of stasis dermatitis
Haemosiderin staining (brown pigments) Ulcers Hair loss Painless scale, itch
46
Outline treatment for stasis dermatitis
Emollients Topical steroid Compression stockings, leg elevation
47
What is lichen simplex dermatitis?
Self-induced eczema due to repeated physical trauma
48
What is acne vulgaris?
Inflammation of pilosebaceous unit that causes a rash, typically in areas high in concentration of these glands (face, neck, chest, back)
49
What causes comedones in acne?
Abnormal keratinisation/desquamation within pilosebaceous unit causes blockage of secretions and comedone formation
50
Open comedones are white/black heads and closed comedones are white/black heads
Open comedones are blackheads and closed comedones are whiteheads
51
List aetiology/risk factors for acne vulgaris
Increased sebum production (increased androgens, CRH) P. acnes infection Occlusion of pilosebaceous unit Dermal inflammation
52
List clinical features of acne
Comedones Seborrhoea Inflammatory papules and pustules, nodules Scars and cysts in severe acne Psych disturbance Develop keloid scars: thick inflamed lesions on trunk and shoulders
53
Outline treatment for mild, moderate and severe acne
Education and psych support, dispel myths Mild: topical benzoyl peroxide +/- azelaic acid, antibiotic Moderate: topical doxycycline/erythromycin + benzoyl peroxide Severe: oral isotretinoin
54
What is acne rosacea?
Chronic relapsing-remitting facial rash usually affecting convex areas
55
List aetiology/risk factors for acne rosacea
``` Largely unknown Chlamydia Demodex mite Spicy food Alcohol ```
56
List clinical features of acne rosacea
``` Rhinophyma Facial flushing NO COMEDONES Telangiectasia Erythema ```
57
Outline treatment of acne rosacea
Avoid irritants Topical azelaic acid + metronidazole Oral azithromycin for chlamydia
58
What is pemphigus vulgaris?
Autoimmune blistering condition caused by IgG produced against desmoglein 3, causing loss of adhesion of epidermis to basal layer
59
List aetiology/risk factors for pemphigus vulgaris
Autoimmunity Genetics Drugs (ACEi, NSAID, phenobarbitol, levodopa)
60
List clinical features of pemphigus vulgaris
Flaccid, superficial, fluid-filled blisters Rupture leaves erosions Nikolsky sign +ve Oral mucosal ulcers
61
What investigation would you do for pemphigus vulgaris?
Skin biopsy for immunofluorescence shows IgG crazy-paving/chicken-wire pattern in epidermis
62
Outline treatment for pemphigus vulgaris
High-dose oral prednisolone | Immunosuppression (rituximab, azathioprine)
63
What is bullous pemphigoid?
Autoimmune blistering condition caused by IgG produced against hemidesmosomes and basement membrane, causing sub-epidermal separation
64
Which is more common - bullous pemphigoid or pemphigus vulgaris?
Bullous pemphigoid
65
List clinical features of bullous pemphigoid
Large, tense bullae Urticated base Nikolsky sign -ve
66
What investigation would you do for bullous pemphigoid?
Skin biopsy for immunofluorescence shows linear IgG deposition along basement membrane
67
Outline treatment for bullous pemphigoid
High-dose oral steroid | Clobetasol propionate cream
68
What is dermatitis herpetiformis?
Rare autoimmune blistering condition caused by IgA cross-reacting with connective tissue matrix proteins, causing sub-epidermal separation
69
Which condition is associated with dermatitis herpetiformis?
Coeliac disease (HLA DQ2)
70
List clinical features of dermatitis herpetiformis
Small, intense itchy blisters usually on elbow/scalp/shoulders/ankles Crusting
71
What investigation would you do for dermatitis herpetiformis?
Skin biopsy histology shows dermal papillary microabscesses | IgA immunofluorescence
72
Outline treatment for dermatitis herpetiformis
Oral dapsone | Gluten-free diet
73
List skin manifestations of hyperthyroidism
``` Moist smooth skin Facial flushing Palmar erythema Fine, thin hair/alopecia Hyperhidrosis Nail changes Hyperpigmentation Pretibial myxoedema Urticaria ```
74
List skin manifestations of hypothyroidism
``` Cold, dry, pale skin Coarse, brittle hair Thickened nails Generalised myxoedema Peri-orbital oedema Facial puffiness ```
75
List skin manifestations of Addison's disease
Palmar crease pigmentation | Buccal pigmentation
76
List skin manifestations of endocrine tumours
Hyperpigmentation Hirsutism Acne Baldness
77
List skin manifestations of systemic sclerosis
``` Pinched mouth Radial furrows Beaked nose Facial telangiectasia Raynaud's phenomenon Dysphagia Sclerodactyly Calcinosis ```
78
What is pityriasis rosea?
Common skin rash tending to occur in epidemics, presenting with solitary herald patch with subsequent truncal eruption of pink oval lesions with scale
79
What is vitiligo?
Acquired de-pigmentation caused by loss of melanocytes
80
List aetiology/risk factors for generalised hair loss
``` Telogen effluvium Endocrine disease (thyroid) Drugs Dietary deficiency (iron, zinc, vit D) Alopecia areata Malnutrition ```
81
What investigations would you do for hair loss?
``` Skin scraping, hair plucking Woods lamp examination Dermoscopy Scalp biopsy Bloods: hormones, FBC, thyroid ```
82
What is alopecia areata?
Autoimmune cause of hair loss in round/spotty distribution all over the body
83
What is hirsutism?
Male-pattern hair growth in response to increased androgenic drive/levels
84
List aetiology/risk factors of hirsutism
``` Familial, genetics Adrenal hyperplasia/tumour PCOS Hyperprolactinaemia Drugs (danazol, glucocorticoids) ```
85
What investigations would you do for hirsutism?
Hormones: testosterone, DHEA, SHBG, LH, FSH | Ovarian USS if indicated
86
What is hypertrichosis?
Excessive hair growth in a non-androgenic distribution
87
List aetiology/risk factors for hypertrichosis
``` Naevi Chronic scarring/inflammation Malnutrition Anorexia Porphyria cutanea tarda Occult malignancy Drugs (minoxidil, phenytoin, ciclosporin) ```
88
What is the most common type of drug skin eruption?
Maculopapular/Exanthematous - up to 2-3 weeks after administration
89
List some drugs that cause exanthematous skin eruptions
``` Penicillin Carbamazepine Allopurinol NSAID Cephalosporins ```
90
When does drug-induced urticaria usually onset?
Within 36 hours of administration but may develop within minutes when re-challenged
91
What is Steven-Johnson syndrome?
Full-thickness epidermal necrolysis, involving mucosal erosions, occurring in response to drugs and/or illness
92
List some drugs that cause Steven-Johnson syndrome
Allopurinol Antibiotics Anticonvulsants NSAID
93
What is the difference between Steven-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN)?
SJS involves up to 30% epidermal detachment | TEN involves more than 30% epidermal detachment
94
List some drugs that cause erythroderma/exfoliative dermatitis
``` Barbiturates Gold Quinine Sulphonamides Carbamazepine Allopurinol ```
95
Fixed drug eruptions are mediated by what cells and occur when?
Mediated by T memory cells | Occur 1-2 weeks after exposure and may persist and reappear with further exposure
96
List some drugs that cause fixed drug eruptions
``` Tetracyclines Phenolphthalein NSAIDs Quinine Oral contraceptive ```
97
List some drugs that cause lichenoid eruptions
B blockers Captopril Thiazides Furosemide
98
Outline general management of drug eruptions
``` Stop likely drug offender Regular emollients for dryness and itch Topical steroid IV hydrocortisone + antihistamine for urticaria Specialist/ICU management if severe ```
99
Outline management of an insect bite
Prevent with insect repellant Topical steroid Antihistamine Treat affected animals and environment
100
What disease can tick bites cause and why?
Lyme disease | Ticks transmit Borrelia Burgdorferi, a spirochaete responsible for lyme disease
101
Describe the first clinical stage of lyme disease
Erythema chronicum migrans, usually up to 14 days after bite, seen as a solitary macule or annular lesion May have mild systemic symptoms
102
Describe the second clinical stage of lyme disease
Borrelia lymphocytoma occurs up to 6 months after the bite, involving firm blue-red swelling or earlobes/nipples Tender local lymphadenopathy Associated numbness/arthralgia/myalgia/paralysis
103
Describe the third clinical stage of lyme disease
Acrodermatitis chronica atrophicans up to 8 years after initial infection, involving blue-red discolouration and atrophy Early inflammation, late atrophy Associated arthritis/neuropathy/pain
104
List non-cutaneous features of lyme disease
``` Fever, malaise, lymphadenopathy Cough Headache Conjunctivitis, keratitis, iritis Meningitis, encephalitis, GBS Heart block, arrhythmia, cardiomyopathy Arthralgia, tendonitis Orchitis, proteinuria, haematuria ```
105
Outline treatment of lyme disease
Doxycycline + amoxicillin/cefuoroxime/erythromycin | IV penicillin/ceftriaxone if severe
106
What systemic reaction may be caused in treating lyme disease in the 1st 24 hours?
Jarisch Herxheimer reaction involving release of endotoxin due to large numbers of organisms being killed
107
What is scabies?
Contagious skin infestation caused by Sarcoptes scabei
108
List aetiology/risk factors for scabies
Poor hygiene Prolonged close/sexual contact Hotel bedding
109
When do symptoms of scabies typically onset?
Individuals can be asymptomatic for up to 6 weeks, then delayed hypersensitivity reaction develops
110
List clinical features of scabies
``` Intensely itchy Red papules Rubbery nodules Burrow lines Vesicles, pustules Involves finger webs, wrist flexures, axillae, abdomen, palms, soles ```
111
How would you make the diagnosis of scabies?
Clinical diagnosis | Skin scraping and microscopy
112
Outline treatment of scabies
``` Permethrin cream Symptom relief (steroid, anti-pruritic) ```
113
What are headlice?
Tiny flightless insects that feed on blood from the scalp | Infestation common in school children
114
List clinical features of headlice
Eggs in scalp hair Itch Papular rash on nape of neck Secondary infection
115
Outline treatment of headlice
Physical removal using fine-tooth comb and shampoo | Anti-parasitic (malathion, dimeticone)
116
What is furunculosis?
Acute deep infection of hair follicles
117
What is staphylococcal scalded skin syndrome?
Epidermolytic exotoxin produced by Staph that causes splitting between desmosomes in granular layer
118
What are the three phases in the growth cycle of a hair?
Anagen (growth) Catagen (involution) Telogen (rest)
119
Most hair is in the anagen phase. True/False?
True
120
What is telogen effluvium?
Reversible/transient hair loss due to stress
121
What treatment may be tried for androgenetic hair loss?
Minoxidil | Anti-androgenic drugs
122
What is Beau's line?
White horizontal line on nail caused by transient arrest in nail growth due to stress/trauma/illness
123
What are main causes of acute paronychia? (inflammation of the nail)
Staph or Strep infection
124
What are the main causes of chronic paronychia?
Candida | Mould
125
What are characteristic histological features of acute eczema?
Spongiosis Acanthosis Inflammatory infiltrate
126
List the main endogenous dermatitis conditions
``` Atopic dermatitis Seborrhoeic dermatitis Discoid eczema Nodular prurigo Lichen simplex chronicus ```
127
What is impetigo?
Highly contagious infection mostly seen in children caused by Staph aureus
128
List clinical features of impetigo
Well-defined honey-coloured crusting on face/nose Erythematous base Superficial flaccid blisters Weeping
129
Outline treatment for impetigo
Topical fusidic acid Oral flucloxacillin Avoid school/close contact
130
What is erysipelas?
Localised cellulitis usually affecting the face caused by Strep pyogenes
131
List clinical features of erysipelas
Sharply defined superficial rash, usually on face Unilateral Associated fever
132
Which antibiotic is used to treat erysipelas?
Penicillin
133
What is cellulitis?
Acute severe infection of skin and soft tissues that is deeper and less well-defined than erysipelas
134
List aetiology/risk factors for cellulitis
``` B-haemolytic Strep (pyogenes) Staph aureus Trauma Vascular disease, poor healing Immunosuppression ```
135
List clinical features of cellulitis
``` Severe pain Swelling Erythema Systemic upset Lymphadenopathy ```
136
Outline treatment of cellulitis
IV benzylpenicillin + PO flucloxacillin | Erythromycin if penicillin-allergic
137
What is necrotising fasciitis?
Life-threatening subcutaneous/soft tissue infection
138
List aetiology/risk factors for necrotising fasciitis
Type 1: polymicrobial (mixed aerobes-anaerobes) | Type 2: group A Strep (pyogenes)
139
List clinical features of necrotising fasciitis
``` Extreme pain Paraesthesia Systemic upset SEPSIS Spreading erythema ```
140
Outline treatment of necrotising fasciitis
Surgical debridement | IV benzylpenicillin + clindamycin
141
Which strain of HPV causes viral warts?
HPV 6 and 11
142
List clinical features of viral warts
``` Skin-coloured/brown lesions Affect large confluence areas on soles Highly infectious May affect genitals Koebner phenomenon ```
143
Outline treatment of viral warts
``` Resolve spontaneously Topical keratolytic (salicyclic acid) Liquid nitrogen cryotherapy Cautery/laser therapy Imiquimod Antiviral if severe ```
144
List aetiology/risk factors for herpes infection
Triggers (sunlight, fever) Immunosuppression Close contact with infected person
145
List clinical features of herpes infection
Burning Itching Grouped, painful vesicles Erythematous base
146
Outline treatment of herpes
Self-limiting | Topical aciclovir
147
What is shingles?
Reactivation of Varicella zoster in dorsal root ganglion of spine causes skin rash in unilateral dermatomal distribution
148
List clinical features of shingles
``` Polymorphic eruption Red papules, vesicles, pustules, crusting Dermatomal distribution May heal with scarring Post-herpetic neuralgia ```
149
Outline treatment of shingles
Analgesia | Oral aciclovir
150
What is molluscum contagiosum?
Pox virus causes chronic infection usually in children
151
List clinical features of molluscum contagiosum
Pink papules with central puntum Expressed white discharge Painless nodules
152
Outline treatment of molluscum contagiosum
Self-resolving Cryotherapy Curettage
153
What are dermatophyte infections?
Fungal infections caused by ringworm organisms (Epidermophyton, Trichophyton, Microsporum)
154
List clinical features of dermatophyte infections
Round, itchy lesions with inflamed border Tinea corporis/cruris/pedis/capitis/unguium Well-demarcated red plaques Between toe clefts Whitening of nails Scale Alopecia
155
How would you investigate fungal skin infections?
Skin scraping microscopy/culture | Wood's lamp fluoresecence
156
Outline treatment for fungal skin infections
``` Antifungal cream (terbinafine, clotrimazole) Oral terbinafine for scalp involvement ```
157
List aetiology/risk factors for Candida infection
Immunosuppression Long-term steroid/inhaler use Poor hygiene
158
List clinical features of Candida infection
Pink, moist "satellite" lesions Peeling Pustules, papules Oral white patches
159
Outline treatment of Candida infection
``` Topical clotrimzaole/terbinafine Oral nystatin Vaginal imidazole Steroid cream if itchy/finalmed Oral fluconazole if not improving ```
160
List clinical features of lichen planus
``` Purple pruritic polyangular planar papules Usually on flexor aspects White lacy markings (Wickham's striae) Scarring alopecia Longitudinal ridges, pterygium on nails Oral/genital lesions ```
161
Outline treatment of lichen planus
Topical steroid | Antifungal (topical, spray)
162
What is a hemangioma?
Benign vascular dilation typically in neonates
163
List clinical features of hemangioma
Strawberry naevus: rapidly enlarging red spot | Pyogenic granuloma: moist red lesion on finger that bleeds easily
164
Outline treatment for hemangioma
Self-resolving Curettage B-blocker Steroid
165
List the main non-melanoma skin cancers
Actinic keratosis Bowen's disease Basal cell carcinoma Squamous cell carcinoma
166
What is actinic keratosis?
Pre-malignant partial thickness dysplasia involving intra-epidermal porliferation of atypical keratinocytes
167
List aetiology/risk factors for actinic keratosis
Sun damage | Fair skin
168
List clinical features of actinic keratosis
Erythematous crumbly yellow-white scale Crusts Tense skin Actinic lentinges
169
Outline treatment for actinic keratosis
Education, sun protection Cryotherapy Surgical excision/curettage if suspect SCC Topical 5-fluoracil/imiquimod/diclofenac
170
What is bowen's disease?
Pre-malignant full thickness dysplasia (carcinoma in-situ)
171
List clinical features of bowen's disease
Slow-growing red scaly plaque Erythema Ill-defined Usually on lower legs of females
172
Outline treatment of bowen's disease
Cryotherapy Topical 5-fluoracil/imiquimod Photodynamic therapy
173
What is the most common skin cancer?
Basal cell carcinoma
174
List aetiology/risk factors for basal cell carcinoma
Sun exposure Mutated TP53 gene PTCH1 mutation causes Gorlin's syndrome
175
List clinical features of basal cell carcinoma
Slow-growing pearly translucent lump with rolled telangiectatic edge Well-define May have central ulceration
176
Outline treatment of basal cell carcinoma
``` Excision Mohs' surgery if recurrent/difficult Photodynamic therapy Radiotherapy if big Cryotherapy/curettage Imiquimod ```
177
List aetiology/risk factors for squamous cell carcinoma
``` Sun exposure Actinic keratosis Bowen's disease Marjolin's ulcer Smoking Chronic inflammation ```
178
List clinical features of squamous cell carcinoma
Ulcerating, hyperkeratotic lesion Firm and irregular Ill-defined Crusted
179
Outline treatment of squamous cell carcinoma
Excision Topical imiquimod/5-fluoracil Radiotherapy
180
What is basal cell papilloma?
Common benign lesion involving overgrowth of basal cell layer AKA seborrhoeic keratosis
181
List aetiology/risk factors for basal cell papilloma
Chronic UV damage Genetics Idiopathic FGR3 mutation
182
List clinical features of basal cell papilloma
Brown greasy "stuck-on" appearance | Irritating, catch on clothes etc.
183
Outline treatment of basal cell papiloma
Leave if asymptomatic Cryotherapy/curettage Excision
184
What are lentigos?
Brown macules/papules that may be pre-malignant
185
What is lentigo maligna?
Precursor to invasive melanoma | melanoma in-situ
186
What are melanocytic naevi?
Benign overgrowth of melanocytes that are mostly not pre-malignant
187
What are the different histological types of melanocytic naevi?
Junctional: at DEJ Compound: into dermis from DEJ Intradermal: in dermis
188
List aetiology/risk factors for melanocytic naevi
Congenital "birthmark" Idiopathic Sun/UV exposure
189
When would you be worried about a melanocytic naevus?
If greater than 5-6mm and irregular and growing
190
What is the fastest increasing skin cancer?
Malignant melanoma
191
List aetiology/risk factors for malignant melanoma
``` Sun/UV exposure Sunburn Sunbed use Sun, sun, suuuuun, all over our bodies Fair skin type More than 50 melanocytic naevi Lentigo maligna Family history BRAF gene mutation ```
192
What are the different histological types of melanoma?
Superficial spreading (most common) Lentigo maligna Acral lentiginous Nodular
193
List clinical features of melanoma
``` Rapidly growing/evolving irregular lesion Varied pigmentation, generally brown Associated ulceration Asymmetry Diameter greater than 6mm ```
194
Outline treatment of melanoma
Excision Sentinel node biopsy Chemotherapy Education and protection from sun
195
Define a chronic leg ulcers
Open lesion between knee and ankle joint that remains unhealed for 4 weeks
196
List aetiology/risk factors for leg ulcers
``` Venous/arterial insufficiency Diabetes DVT Malignancy Vasculitis Inflammation Obesity ```
197
List clinical features of venous ulcers
``` Superficial Venous disease (varicose veins) Haemosiderin staining Venous eczema Lipidodermatosclerosis Atrophie blanche Generally painless ```
198
List clinical features of arterial ulcers
``` Deep, punched out Tendon exposure Foot/toes/pressure points Hair loss Cold limb Generally painful ```
199
What measurement is essential to make before applying pressure bandaging?
ABPI
200
State the cut-offs for ABPI
0.8 - 1.3 is normal Less than 0.8 indicates vascular disease Greater than 1.5 indicates calcificiation
201
Outline treatment of venous ulcers
``` De-slough agent Graduated compression greater at ankle than below knee Non-adherent dressing Weekly/daily changing Aim to heal by 12 weeks Emollients/steroid for eczema ```
202
Outline treatment of arterial ulcers
``` Pain relief Lifestyle changes Aspirin Treat infection Soffban, crepe bandage toe to knee to reduce oedema Vascular surgery Topical -ve pressure treatment ```
203
What are port-wine stains?
Naevus flammeus Capillary malformation results in macular lesion that is lifelong and usually unilateral Do not extend but may get hyperplasia
204
What is the commonest genodermatosis?
Neurofibromatosis type 1
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What is neurofibromatosis type 1?
Autosomal dominant defect in NF1 amino acid which inactivates oncogenes, causing neuroectodermal disorder
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List clinical features of neurofibromatosis
``` Cafe au lait macules Axillary freckles Lisch nodules in iris Learning difficulty Skeletal dysplasia Fleshy skin tags/neurofibromas ```
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What is tuberous sclerosis?
Autosomal dominant defect in TSC1 (hamartin) or TSC2 (tuberin) that allows hamartoma development
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List clinical features of tuberous sclerosis
``` Ash leaf (depigmented) macules Dental pits Periungual fibromata Adenoma sebaceum Shagreen patch Epilepsy Mental retardation Autism Lipoma ```
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Outline treatment for neurofibromatosis type 1 and tuberous sclerosis
Surgical removal of skin lesions Laser therapy Surveillance Treat symptoms/complications
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What is epidermolysis bullosa?
Inherited skin fragility involving mutated skin structure proteins
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What are the histological subtypes of epidermolysis bulosa?
Simplex: involves epidermis Junctional: involves DEJ Dystrophic: involves dermis
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List clinical features of epidermolysis bullosa
``` Recurrent blisters and erosions Poor healing Milia Scarring Dystrophic nails ```
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Outline treatment of epidermolysis bullosa
Dressing wounds Topical antibacterial Sterile drainage
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List hazards of UV exposure
Sunburn Eye damage Skin cancer Photosensitivity
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Sort the different types of UV radiation from longest to shortest wavelength (most penetrating to least penetrating)
UVA UVB UVC
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What are the main forms of therapeutic UV radiation?
Phototherapy (UVB) Photochemotherapy (Psoralen UVA) (PUVA) Photodynamic therapy
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List Fitzpatrick skin types
``` I: always burns II: usually burns, can tan III: usually tans, can burn IV: always tans V: brown skin VI: black skin ```
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When does UVB "sunburn" erythema onset? What mediates the erythema?
Onset 2-4 hours Peak 12-24 hours Mediated by prostaglandins
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When does PUVA erythema onset? What mediates the erythema?
Onset 24 hours Peak 96 hours Mediated by oxygen/free radicals
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It is more likely to develop squamous cell carcinoma with cumulative sunburn and melanoma with acute sunburn. True/False?
True
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List the main immunological photodermatoses
``` Polymorphic light eruption Actinic prurigo Solar urticaria Chronic actinic dermatitis Hydro vacciniforme ```
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What is polymorphic light eruption?
Delayed reaction to sunlight involving non-scarring papulo-vesicular rash and hardening of skin
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When does actinic prurigo typically onset?
Childhood
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What is solar urticaria?
Rare acute type 1 hypersensitivity reaction to sunlight
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List the main genetic photodermatose
Xeroderma pigmentosum
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What is xeroderma pigmentosum?
Rare, autosomal recessive failure of DNA repair, causing rapid photo-ageing of skin and skin cancer Often death in teens
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List common drugs that cause photosensitivity
``` Psoralens (lime, celery) Antibiotics (sulfonamides, tetracycline, fluoroquinolones) Diuretics NSAIDs Quinine Amiodarone ```
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What are porphyrias?
Inherited/acquired photosensitivty caused by deficit in enzymes in the haem pathway, resulting in build-up of porphyrins that react to light
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Which enzyme is deficient in porphyria cutanea tarda?
Uroporphyrinogen decarboxylase
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List aetiology/risk factors for porphyria cutanea tarda
``` Haemochromoatosis HIV Hepatitis C Alcohol Oestrogen excess Iron excess ```
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List clinical features of porphyria cutanea tarda
``` Vesicles/bullae in sun-exposed sites Hypertrichosis Hyperpigmentation Skin fragility Scarring ```
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What investigations would you do for porphyria cutanea tarda?
LFTs typically deranged High serum ferritin Plasma/faecal/urinary porphyrins
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Which enzyme is deficient in erythropoietic porphyria?
Ferrochelatase
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List clinical features of erythropoietic porphyria
Swelling Burning pain Young kid tingling/itchy skin in sunlight Gallstones
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Which enzyme is deficient in acute intermittent porphyria?
PBG deaminase
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List aetiology/risk factors for acute intermittent porphyria
Autosomal dominant Alcohol Contraception (increased progesterone)
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List clinical features of acute intermittent porphyria
Neuro + autonomic upset Nausea Pain
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Outline treatment of porphyrias
``` Avoid sunlight Remove precipitants Venesection if ferritin high Support and education Haemarginate in AIP ```
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What is psoriasis?
Chronic inflammatory skin condition involving uncontrolled epidermal proliferation (parakeratosis) and T-cell-driven inflammatory infiltration of epidermis and dermis
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List aetiology/risk factors for psoriasis
Genetics, strong family history Triggers (stress, infection, trauma, alcohol, obesity) Smoking Drugs (B-blockers, lithium, antimalarials) TH1 + TH17 cells
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List clinical features of psoriasis
``` Symmetrical well-defined itchy red plaques Scale Usually affects extensors Nail changes (pitting, onycholysis, subungual keratosis) Koebner phenomenon Auspitz sign Small plaques (guttate) in young Pustules if severe Psoriatic arthritis Erythroderma with systemic upset ```
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What investigations would you do for psoriasis?
Skin biopsy for histology shows parakeratosis, epidermal proliferation and microabscesses with inflammatory infiltrate
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Outline treatment for psoriasis
``` Education, avoid triggers/stressors Emollients for cooling Vitamin D analogue (calcipotriol) Topical steroid Coal tar preparations Short-term retinoid (Acitretin) Dithranol, tazarotene if unresponsive Immunosuppression (methotrexate, etanercept, infliximab) Phototherapy ```
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List infective skin manifestations of HIV
``` HIV seroconversion disease Thrush Molluscum contagiosum Herpes Varicella zoster Cryptococcus Oral hairy leukoplakia ```
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List inflammatory manifestations of HIV
Seborrhoeic dermatitis Psoriasis Eosinophillic folliculitis
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What malignancy associated with HIV has prominent skin features?
Kaposi sarcoma
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What causes Kaposi's sarcoma?
Herpes hominis virus (HHV-8)
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List clinical features of Kaposi's sarcoma
Purpule macules Papules, nodules Plaques affecting skin and mucosa Periorbital purpura (racoon eyes)
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Outline treatment of Kaposi's sarcoma
HAAR Radiotherapy Interferon-alpha
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Dermatitis to latex is type 1 hypersensitivity. True/False?
True | Do skin prick IgE test, not patch test
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What are halo naevi?
Immune reponse to a mole | Has a "fried egg" appearance
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What are blue naevi?
Result due to melanocytes that failed to fully migrate from neural cell crest
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What is Sturge Weber syndrome?
Port wine staining affects CN V1 nerve distribution | Associated with vascular malformations on ipsilateral side, including in the brain
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What is Klippel Trenauney syndrome?
Capillary + venous malformation that causes progressive limb overgrowth with purpuric rash
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If a strawberry naevus affects the eye in children, what might develop?
Ambliopia or other visual field defects - refer urgently to ophthalmology
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How long do individual lesions of urticaria normally last?
Up to 24 hours Acute urticaria: up to 6 weeks Chronic urticaria: over 6 weeks
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Which cell is responsible for releasing inflammatory mediators that cause urticaria?
Mast cell
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List causes of urticaria
``` Allergy (not usually chronic) Direct chemicals Physical (dermographism, vibration, cold, solar) Autoimmune conditions Infection Dermatitis ```
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What treatments are available to block the effects of mediators released from mast cells?
Antihistamines Leukotriene antagonists Serotonin antagonists
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Which histamine receptors are relevant in urticaria?
H1 H2 H4
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What is anaphylaxis?
Acute angioedema, often with urticaria, with respiratory compromise and hypotension Life-threatening!
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Outline treatment of anaphylaxis
``` Ensure airway patent (ABCDE) IM adrenaline IV antihistamine IV hydrocortisone IV fluids if hypotensive ```