Dermatology Flashcards
Acanthosis Nigricans - pathophysiology and causes
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
Mild to moderate acne treatment:
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
Moderate to severe acne treatment:
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
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?
Tetracyclines
Erythromycin
6 months
No, should always be with BPO/isotretinoin
Oral and topical ABx should not be prescribed together
Actinic keratosis - Mx options:
Prevention - no further sun exposure
Fluorouracil cream 2-3 week course
topical diclofenac
topical imiquimod
cryotherapy, curretage and cautery
Bullous pemphigoid
Pathophysiology:
Is there mucosal involvement?
Immunofluorescence:
Treatment?
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
Pathophysiology of severe burns:
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
Parkland formula:
Volume of fluid = total body surface X Weight (kg) X 4
half of the fluid given in the first 8 hours
What is chondrodermatitis nodularis helicis?
cause:
treatment:
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
Dermatitis herpetiformis
Associated condition:
Immunoglobulin:
Diagnosis:
Coeliac disease
IgA
Skin biopsy: direct immunofluoresence show deposition of IgA in upper dermis
Eczema herpeticum:
Infective organism:
Buzzword:
Treatment:
Herpes simplex 1 or 2
Monomorphic punched out lesions
IV aciclovir
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
Hypersensitivity
Major and minor
Target lesions
Herpes simplex
Penicillin, sulphonamides, carbamazepine, allopurinol, NSAIDs, COCP
When there is mucosal involvement
Guttate psoriasis
Lesions look like:
Preceeded by:
Treatment:
Tear drop
Streptococcal infection 2-4 weeks prior to lesions
Most cases resolve spontaneously within 2-3 months - no evidence for use if antibiotics
Hereditary haemorrhagic telangiectasia
4 main diagnostic criteria
Epistaxis
Telangiectases
Visceral lesions - GI teleangiectasiam AVM, hepatic AVM
Family history
Most common cause of hirsutism:
PCOS
Hyperhidrosis
Treatment options:
Aluminium chloride (1)
ionotophoresis
Botulinium toxin
Surgery
Impetigo
2 causative bugs:
incubation period:
Management:
If resistant:
Extensive disease:
School exclusion:
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.
Keratoacanthoma
Nickname:
Commonest in:
Treatment and prognosis:
Volcano tumour
Old people
Benign epithelial tumour but urgently excised to rule out SCC
Leukoplakia
What is it?
More common in smokers:
Investigations:
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)
Lichen planus
Appearance:
Treatment:
drug causes:
polygonal shape with white lines -> wickham’s striae. Itchy papular rash most common on the palms.
Topical steroids
Benzydamine mouthwash
Gold, quinine, thiazides
Lichen sclerosus
Where does it affect?
In who?
increased risk of?
Treatment:
Genitals
Old women
Vulval cancer
Topical steroids and emollients
4 types of melanoma
Commonest:
Most agressive:
Prognosticate using
Superficial spreading (commonest)
Nodular melanoma (most agressive)
Lentigo maligna melanoma
Acral lentiginous
Breslow’s thickness after biopsy
Molluscum contagiosum
Causative organism:
Treatment:
If HIV positive ->
Pox virus
Usually self-limiting -> spontaneous resolution within 18 months
Urgent referral to HIV specialist
Pellagra
What is it?
3Ds?
Which drug can cause?
Deficiency of niacin (nicotinic acid)
Dermatitis, diarrhoea, dementia
Isoniazid -> inhibits conversion to niacin
Pemphigus vulgaris
Antibodies against:
Difference from bullous pemphigoid:
Specific sign:
On biopsy:
Management:
Desmoglein 3
Mucosal involvement common
Nikolski sign -> spread of bullae with pressure
Acantholysis
Steroids (1)
Immunosupression (2)
Pityriasis rosea
Early sign on skin:
Management:
Herald patch first followed by multiple raised oval lesions 1-2 weeks later
Self limiting
Pityriasis versicolor
Type of infection:
Appearance:
Treatment:
Fungal -> Melassezia furfur
Hypopigmented, pink or brown (hence versicolor) More notice following a sun tan
Topical antifungal: ketoconazole shampoo
Psoriasis
Exacerbating factors:
Drugs: beta blockers, lithium, antimalarials, NSAIDs, ACE inhibitors, infliximab
Withdrawal of steroids
Trauma
Alcohol
Streptococcal infection may trigger guttate psoriasis
Psoriasis management: Primary care
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
Psoriasis management: Secondary care
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
Pyoderma gangrenosum
What is it?
Causes:
Treatment:
Neutrophilic dermatosis, non-infective inflammatory disorder. Uncommon cause of skin ulceration
Idiopathic (50%)
Inflammatory bowel disease
Rheumatological
Oral steroids, immunosuppression
Adverse effects of retinoids
Teratogenicity -> females should use two forms of contraception
Dry skin, lips mouth
Low mood
raised triglycerides
Nosebleeds
Intracranial hypertension -> Do not combine with tetracyclines
Management of rosacea
Predominant erythema/flushing: topical brimonidine gel
Mild/moderate: Topical Ivermectin
Moderate to severe: Topical ivermectin with oral doxycycline
Scabies management
Contacts?
1) Permethrin 5%
2) Malathion 0.5%
Pruritus may persist for 4-6 weeks
All contacts should be treated at same time.
Seborrhoeic dermatitis
Caused by:
Associated conditions:
Management:
Chronic dermatitis -> Melassezia furfur
HIV, Parkinsons
Topical antifungals - ketoconazole
Topical steroids - short periods
Recurrences are common
Shingles management
Paracetamol and NSAIDS for analgesia
Antivirals within 72 hours for the majority of patients ->
This reduces incidence of post-herpetic neuralgia
Skin disorders associated with malignancy:
Acanthosis nigricans:
Acquired ichythyosis:
Hypertrichosis lanuginosa:
Dermatomyositis:
Erythema gyratum repens
Erythroderma:
Migratory thrombophlebitis
Pyoderma gangrenosum:
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
Strawberry Naevi
Presentation and progression
Risk increased by:
Treatment
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
Drugs known to cause toxic epidermal necrolysis
Treatment:
Phenytoin
Sulphonamides
Allopurinol
Penicillins
Carbamazepine
NSAIDs
IV Ig
Treatment for allergic urticaria
Duration of course:
For severe resistant episodes:
Loratidine or cetirizine (non-sedating antihistamine)
up to 6 weeks
Prednisolone
Normal ABPI
Venous disease ABPI
Arterial ABPI
Treatment for venous ulcers:
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
