Derm Flashcards
What is a small, crusty/scaly lesion that is pink, brown, red, or neutral, which develops as a consequence of chronic sun exposure?
Actinic/solar keratoses
What is the treatment of actinic keratoses?
2-3 weeks fluorouracil cream
Topical imiquimod
What benign epithelial tumour looks like a volcano then grows to become a crater filled with keratin?
Keratoacanthoma
What are the characteristics of basal cell carcinoma?
Morphoeic Firm/rough/waxy Pearly/flesh coloured Papular Telangiectasia Lateral ulceration
What is the treatment of BCC?
Routine referral
Topical imiquimod/fluorouracil
Moh’s surgery
What are 6 risk factors for SCC?
Sunlight Actinic keratoses/Bowen's disease Immunosuppression Smoking PUVA therapy for psoriasis Oculocutaneous albinism
What are the characteristics of SCCs that arise in a chronic scar?
Aggressive
Increased risk of metastases
What is the management of SCC?
<20mm diameter: excision with 4mm margins
>20mm diameter: excision with 6mm margins
What is the most important prognostic factor in malignant melanoma?
Breslow thickness (invasion depth)
50% malignant melanoma patients have which mutation?
BRAF mutation
What is vemurafenib?
BRAF inhibitor which improves survival in malignant melanoma
What are the 2 types of contact dermatitis?
Irritant
Allergic
What is skin prick test useful for?
Pollen and food allergies
What does RAST do?
Determines that amount of IgE that reacts specifically with suspected or known allergens
What type of dermatitis is skin patch testing used for?
Contact
What are the characteristics of eczema herpeticum?
Monomorphic
Punched out erosions
Pruritic blisters/vesicles
What is the treatment of eczema herpeticum?
IV aciclovir
What fungi is seborrhoeic dermatitis an inflammatory reaction to?
Malassezia furfur
What is seborrhoeic dermatitis associated with?
HIV
Parkinsons
What is the treatment of keyloid scars?
Intra-lesional steroids e.g. triamcinolone
What is the cause of livedo reticularis?
Obstruction of capillaries resulting in swollen venules
What are the causes of livedo reticularis?
SLE PAN Cryoglobulinaemia APS Homocystinuria
What is the pathophysiology of dermatitis herpetiformis?
Deposit of IgA in the dermis
What rash is associated with lung cancer?
Erythema gyratum repens
What rashes are associated with lymphoma?
Erythroderma
Acquired ichthyosis
What rashes are associated with diabetes?
Necrobiosis lipoidica
Candidiasis
Lipotrophy granuloma annulare
What are 5 causes of erythema nodosum?
Strep infection Sarcoid Pregnancy IBD Penicillins/sulphonamides/COCP
What are 5 causes of pyoderma gangrenosum?
Idiopathic IBD CTD Myeloproliferative disorders SLE PBC
What are 6 causes of hirsuitism?
PCOS Cushing's CAH Obesity (insulin resistance) Androgen therapy Phenytoin/steroids
What is the scoring system used for hirsuitism?
Ferriman-Gallwey
What are the treatments for hirsuitism?
Weight loss
Co-cyprindiol/ethinylestradiol and drospirenone
Topical eflornithine
What are 6 causes of hyperptrichosis?
Porphyria cutanea tarda Minoxidil Ciclosporin Congenital hypertrichosis lanuginosa Anorexia
What rash is seen in glucagonoma?
Necrolytic migratory erythema
What is the cause of pityriasis/tinea versicolor?
Superficial infection with malassezia furfur
What is the treatment of pityriasis versicolor?
Topical ketoconazole
What is the cause of pityriasis rosea?
Reactivation of HHV 6 and 7
What is characteristic of pityriasis rosea?
Herald patch
What rash occurs with overgrowth of the diphtheroid corynebacterium minutissimum?
Erythasma
What occurs when erythasma is examined with Wood’s light?
Coral red fluorescence
What is the treatment of erythasma?
Topical miconazole –> PO erythromycin
What is the pathophysiology of acne vulgaris?
Follicular epidermal hyperproliferation –> keratin plug
Obstruction of pilosebaceous follicle
Colonisation by anaerobic bacterium propiobacterium acnes + inflammation
What is the initial and 2nd line treatment of acne?
Single topical therapy e.g. retinoids, benzoyl peroxide
Then, combination therapy (2 of retinoids, benzoyl peroxide, antibiotic)
What is the 3rd line treatment of acne?
PO antibiotic e.g. tetracyclines (not preg) or COCP
Co-prescribe topical retinoid/benzoyl peroxide to reduce risk of abx resistance
What is the 4th line treatment of acne?
PO isotretinoin
What are 6 side effects of isoretinoin?
Depression Dry skin, eyes, mouth Teratogenic Raised triglycerides Hair thinning IIH
What is erythroderma?
95% skin involved in a rash of any kind
What molecule is implicated in the development of rosacea?
Cathelicidins - innate response to chronic exposure to UV radiation
What is the treatment of rosacea?
Topical metronidazole –> oxytetracycline
What is the primary care treatment of psoriasis?
- Potent steroid OD + vit D analogue OD (applied separately)
- Vit D analogue BD
- Potent steroid BD or coal tar OD or BD
What type of phototherapy is used for psoriasis in secondary care?
Narrowband UV B light 3x week
OR
Psoralen + UV A light (photochemotherapy, PUVA)
What are the risks of phototherapy?
Skin ageing
SCC
What are 4 other systemic treatments of psoriasis in secondary care?
PO methotrexate
Ciclosporin
Systemic retinoids
Anti-TNFs
Name 6 factors that exacerbate psoriasis?
Beta blockers Lithium Antimalarials NSAIDs ACEIs Trauma Alcohol
What is the treatment of guttate psoriasis?
Ultraviolet B phototherapy
What is the treatment of flexural psoriasis?
Topical steroids
What is Nikolsky’s sign?
Epidermis separates with mild lateral pressure
What is the treatment of toxic epidermal necrolysis?
Stop causative drug
Supportive care
IVIG
Ciclosporin/CYC
What drugs cause toxic epidermal necrolysis?
N-CAPS
NSAIDs Carbamazepine Allopurinol Phenytoin/penicillin Sulphonamides
What are the most common causes of erythema multiforme?
HSV
Mycoplasma
Strep
What are the features of erythema multiforme?
Target lesions
Back of hands/feet –> torso
Upper limb>lower limb
Kobner phenomenon
What type of ulcer is usually seen above the medial malleolus?
Venous
What ABPI result is abnormal?
<0.9 - arterial disease
>1.3 - calcification
What is the management of venous ulcer?
Compression bandaging PO pentoxiflline (peripheral vasodilator)
What is the condition of a neoplastic proliferation of mast cells?
Systemic mastocytosis
What are the features of systemic mastocytosis?
Urticaria pigmentosa
Darier’s sign
Flushing
Abdo pain (from increased histamine -> gastric acid)
How is systemic mastocytosis diagnosed?
Monocytosis
Raised serum tryptase
Raised urinary histamine
What are the symptoms of zinc deficiency caused by TPN?
Acrodermatitis herpetiformis Perioral dermatitis Alopecia Short stature Hepatosplenomegaly
What are the features of hereditary haemorrhagic telangiectasia?
Epistaxis Telangiectasias Visceral lesions e.g. GI telangiectasia Pulmonary/cerebral/spinal AVMs Family history
What are the associations of yellow nail syndrome?
Congenital lymphoedema
Pleural effusions
Bronchiectasis
Chronic sinus infections
What are the causes of bullous pemphigoid?
Chronic skin disease NSAIDs Furosemide Captopril Penicillamine
What is the autoantigen in bullous pemphigoid?
Type 17 collagen
Hemidesmosomal proteins BP180 and BP230
What is the function of type 17 collagen?
Forms the junction between the epidermis and BM of dermis
What are the features of bullous pemphigoid?
Tense subepidermal blisters/bullae on urticated base
Painful and pruritic
Mucus membrane involvement in 25%
Patient otherwise well
What is seen on histology of bullous pemphigoid?
Deposits of IgG and C3 at dermal/epidermal junction on epidermis half
Intact epidermis
Fibrin and inflammatory infiltrate, eosinophil predominance
What is the treatment of bullous pemphigoid?
PO pred –> AZA/MMF
What type of patient gets pemphigoid vulgaris?
Older age Female Ashkenazi Jews Pregnancy Stress
What is the autoantigen in pemphigoid vulgaris?
Desmogleins DSG3 on surface of keratinocytes
What are the features of pemphigus vulgaris?
Flaccid epidermal blisters on normal or erythematous skin
Painful not pruritic
Mucus membrane involvement
How is pemphigus vulgaris diagnosed?
Direct and indirect immunofluorescence
ELISAs for DSG1 and DSG3 in serum
What is the treatment pemphigus vulgaris?
PO pred –> plasmaphresis with AZA/CYC –> IVIG
What are the risk factors for lichen planus?
Hepatitis C
Female
PBC
What are the features of lichen planus?
Purple, pruritic, polyangular, planus, papules
Flexor surfaces of upper extremities, mucus membranes
Wickham’s striae
Scarring alopecia
Longitudinal nail ridges
What is the treatment of lichen planus?
Mod potent topical steroids +/- antifungals
PUVA
PO pred
Oral fluticasone spray
What is the most common type of melanoma?
Superficial spreading
Growing mole
What is nodular melanoma?
2nd most common
Red or black lump that bleeds/oozes
What is lentigo maligna?
Less common melanoma
Older people
Chronically sun exposed skin
Growing mole
What is the rarest form of melanoma?
Acral lentiginous Subungal pigmentation (Hutchinson's sign) or on palms/feet