Dermatology Flashcards

1
Q

Acanthosis Nigricans - pathophysiology and causes

A

Insulin resistance -> hyperinsulinaemia -> stimulation of keratinocytes and dermal fibroblasts proliferation and IGFR-1.

T2DM
GI cancer (gastroadenocarcinoma)
Obesity
PCOS
Acromegaly
Hypothyroidism

Essentially anything that causes increased insulin via insulin resistance can cause this

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2
Q

Mild to moderate acne treatment:

A

12 week course:
topical adapalene with topical benzoyl peroxide or
topical tretinoin with topical clindamycin
a fixed combination of topical benzoyl peroxide with topical clindamycin

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3
Q

Moderate to severe acne treatment:

A

12 week course of:

topical adapalene with topical benzoyl peroxide or
topical tretinoin with topical clindamycin
a fixed combination of topical benzoyl peroxide with topical clindamycin PLUS
ORAL DOXYCYCLINE OR LYMECYCLINE

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4
Q

Acne treatment: Which antibiotics are to be avoided in pregnant or breast feeding women?

What should be used in its place?

Oral antibiotic therapy should not exceed:

Should antibiotics be prescribed in isolation?

A

Tetracyclines

Erythromycin

6 months

No, should always be with BPO/isotretinoin
Oral and topical ABx should not be prescribed together

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5
Q

Actinic keratosis - Mx options:

A

Prevention - no further sun exposure
Fluorouracil cream 2-3 week course
topical diclofenac
topical imiquimod
cryotherapy, curretage and cautery

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6
Q

Bullous pemphigoid

Pathophysiology:

Is there mucosal involvement?

Immunofluorescence:

Treatment?

A

sub epidermal blistering secondary to development of antibodies against hemidesmosomal BP180 BP230

No mucosal involvement in Bullous pemphigoid - Mouth is spared.

IgG and C3 at the dermoepidermal junction

Oral corticosteroids, refer derm, topical CS, ABx. and immunosuppressants also used

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7
Q

Pathophysiology of severe burns:

A

Local response with progressive tissue loss and release of inflammatory cytokines.
Systemically, there are cardiovascular effects from fluid loss and sequestration of fluid into the third space.
Catabolic response -> immunosuppression is common with large burns and bacterial translocation from gut can cause sepsis

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8
Q

Parkland formula:

A

Volume of fluid = total body surface X Weight (kg) X 4
half of the fluid given in the first 8 hours

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9
Q

What is chondrodermatitis nodularis helicis?

cause:

treatment:

A

common and benign condition categorised by development of painful nodule in the ear

Persistent pressure on the ear

reducing pressure on the ear : sleep aids/protectors, steroids, surgery

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10
Q

Dermatitis herpetiformis

Associated condition:
Immunoglobulin:
Diagnosis:

A

Coeliac disease
IgA
Skin biopsy: direct immunofluoresence show deposition of IgA in upper dermis

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11
Q

Eczema herpeticum:
Infective organism:
Buzzword:
Treatment:

A

Herpes simplex 1 or 2
Monomorphic punched out lesions
IV aciclovir

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12
Q

Erythema multiforme
Type of reaction:
Divided into which two forms:
Lesions look like:
Most common cause (virus):
Drug causes:
When does this become erythema multiforme major

A

Hypersensitivity
Major and minor
Target lesions
Herpes simplex

Penicillin, sulphonamides, carbamazepine, allopurinol, NSAIDs, COCP

When there is mucosal involvement

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13
Q

Guttate psoriasis
Lesions look like:
Preceeded by:
Treatment:

A

Tear drop
Streptococcal infection 2-4 weeks prior to lesions
Most cases resolve spontaneously within 2-3 months - no evidence for use if antibiotics

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14
Q

Hereditary haemorrhagic telangiectasia
4 main diagnostic criteria

A

Epistaxis
Telangiectases
Visceral lesions - GI teleangiectasiam AVM, hepatic AVM
Family history

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15
Q

Most common cause of hirsutism:

A

PCOS

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16
Q

Hyperhidrosis
Treatment options:

A

Aluminium chloride (1)
ionotophoresis
Botulinium toxin
Surgery

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17
Q

Impetigo
2 causative bugs:
incubation period:
Management:
If resistant:
Extensive disease:
School exclusion:

A

Staphylococcus aureus or streptococcus pyogenes
4 to 10 days
If not systemically unwell -> hydrogen peroxide 1%
topical antibiotic creams - topical fusidic acid
Topical mupirocin
Oral flucloxacillin

School exclusion:
Excluded from school until lesions are crusted and healed or 48 hours after commencing antibiotic treatment.

18
Q

Keratoacanthoma
Nickname:
Commonest in:
Treatment and prognosis:

A

Volcano tumour
Old people
Benign epithelial tumour but urgently excised to rule out SCC

19
Q

Leukoplakia
What is it?
More common in smokers:
Investigations:

A

Pre-malignant condition presents as white, hard spots on the mucous membranes of the mouth. More common in smokers.

Biopsies to exclude alternative diagnoses (SCC)

20
Q

Lichen planus
Appearance:
Treatment:
drug causes:

A

polygonal shape with white lines -> wickham’s striae. Itchy papular rash most common on the palms.

Topical steroids
Benzydamine mouthwash

Gold, quinine, thiazides

21
Q

Lichen sclerosus
Where does it affect?
In who?
increased risk of?
Treatment:

A

Genitals
Old women
Vulval cancer
Topical steroids and emollients

22
Q

4 types of melanoma
Commonest:
Most agressive:
Prognosticate using

A

Superficial spreading (commonest)
Nodular melanoma (most agressive)
Lentigo maligna melanoma
Acral lentiginous

Breslow’s thickness after biopsy

23
Q

Molluscum contagiosum
Causative organism:
Treatment:
If HIV positive ->

A

Pox virus
Usually self-limiting -> spontaneous resolution within 18 months
Urgent referral to HIV specialist

24
Q

Pellagra
What is it?
3Ds?
Which drug can cause?

A

Deficiency of niacin (nicotinic acid)
Dermatitis, diarrhoea, dementia
Isoniazid -> inhibits conversion to niacin

25
Q

Pemphigus vulgaris
Antibodies against:
Difference from bullous pemphigoid:
Specific sign:
On biopsy:
Management:

A

Desmoglein 3

Mucosal involvement common

Nikolski sign -> spread of bullae with pressure

Acantholysis

Steroids (1)
Immunosupression (2)

26
Q

Pityriasis rosea
Early sign on skin:
Management:

A

Herald patch first followed by multiple raised oval lesions 1-2 weeks later
Self limiting

27
Q

Pityriasis versicolor
Type of infection:
Appearance:
Treatment:

A

Fungal -> Melassezia furfur

Hypopigmented, pink or brown (hence versicolor) More notice following a sun tan

Topical antifungal: ketoconazole shampoo

28
Q

Psoriasis
Exacerbating factors:

A

Drugs: beta blockers, lithium, antimalarials, NSAIDs, ACE inhibitors, infliximab
Withdrawal of steroids

Trauma

Alcohol

Streptococcal infection may trigger guttate psoriasis

29
Q

Psoriasis management: Primary care

A

1) Corticosteroid OD plus Vitamin D analogue OD applied seperately -> 4 weeks trial

If no improvement after 8 weeks ->
2) Vitamin D analogue BD

3) Corticosteroid BD or coal tar preparation OD
short acting dithranol can be used

Steroids should be used for no longer than 8 weejs at a time and a four week break should be taken prior to starting the next course to prevent steroid atrophy

30
Q

Psoriasis management: Secondary care

A

Narrowband UVB light therapy -> 3 times per week
Photo chemotherapy also used: Psoralen plus UV A light

Systemic therapy:
Methotrexate first line (particularly useful if secondary joint disease)
Biologic agents: Infliximba, etanercept, adalimumab

30
Q

Pyoderma gangrenosum
What is it?
Causes:
Treatment:

A

Neutrophilic dermatosis, non-infective inflammatory disorder. Uncommon cause of skin ulceration

Idiopathic (50%)
Inflammatory bowel disease
Rheumatological

Oral steroids, immunosuppression

31
Q

Adverse effects of retinoids

A

Teratogenicity -> females should use two forms of contraception
Dry skin, lips mouth
Low mood
raised triglycerides
Nosebleeds
Intracranial hypertension -> Do not combine with tetracyclines

31
Q

Management of rosacea

A

Predominant erythema/flushing: topical brimonidine gel

Mild/moderate: Topical Ivermectin

Moderate to severe: Topical ivermectin with oral doxycycline

32
Q

Scabies management
Contacts?

A

1) Permethrin 5%
2) Malathion 0.5%

Pruritus may persist for 4-6 weeks

All contacts should be treated at same time.

33
Q

Seborrhoeic dermatitis
Caused by:
Associated conditions:
Management:

A

Chronic dermatitis -> Melassezia furfur

HIV, Parkinsons
Topical antifungals - ketoconazole
Topical steroids - short periods
Recurrences are common

34
Q

Shingles management

A

Paracetamol and NSAIDS for analgesia
Antivirals within 72 hours for the majority of patients ->
This reduces incidence of post-herpetic neuralgia

35
Q

Skin disorders associated with malignancy:
Acanthosis nigricans:

Acquired ichythyosis:

Hypertrichosis lanuginosa:

Dermatomyositis:

Erythema gyratum repens

Erythroderma:

Migratory thrombophlebitis

Pyoderma gangrenosum:

A

Acquired ichythyosis: lymphoma

Hypertrichosis lanuginosa: gastric and lung

Dermatomyositis: ovarian and lung

Erythema gyratum repens: lung cancer

Erythroderma: lymphoma

Migratory thrombophlebitis: pancreatic malignancy

Pyoderma gangrenosum: myeloproliferative disorders

36
Q
A
37
Q

Strawberry Naevi
Presentation and progression
Risk increased by:
Treatment

A

Capillary haemangioma -> not usually present at birth but may present rapidly in first few months of life.

Mothers who have undergone chorionic villus sampling

90% resolve by 10 years of age.

Red

38
Q

Drugs known to cause toxic epidermal necrolysis
Treatment:

A

Phenytoin
Sulphonamides
Allopurinol
Penicillins
Carbamazepine
NSAIDs

IV Ig

39
Q

Treatment for allergic urticaria
Duration of course:
For severe resistant episodes:

A

Loratidine or cetirizine (non-sedating antihistamine)
Prednisolone

40
Q

Normal ABPI
Venous disease ABPI
Arterial ABPI

Treatment for venous ulcers:

A

Normal ABPI: 0.9-1.2
Venous disease ABPI: >1.2
Arterial ABPI: <0.9 or >1.3 (calcification)

Compression bandaging: Four layer
Oral Pentoxifylline improves healing