Dermatology Flashcards
What is actinic keratosis?
Pre-malignant sun damage
What does actinic keratosis look like?
Small, crusty, scaly lesions
May be pink, brown, red
How can you prevent actinic keratosis?
Avoid sun-exposure
Sun-cream
How do we treat actinic keratosis?
Fluorouracil cream (2-3 week course), often give hydrocortisone after for the redness
Topical diclofenac if mild
Cryotherapy
Cutterage and cautery
What does an erythema ab igne rash look like?
Reticulated, erythematous patches with hyperpigmentation and telangiectasia
What causes erythema ab igne?
Over-exposure to infrared radiation. If left untreated can lead to SCC
What is a keratoacanthoma?
A benign epithelial tumour
Features of a keratoacanthoma?
Common with advancing age
Initially a smooth dome-shaped papule
Rapidly grows to become a crater centrally filled with keratin
How do we treat keratoacanthomas?
They go away on their own after 3 months, but should be excised as they are difficult to clinically distinguish from SCC’s
What are fungal nail infections most commonly caused by?
Dermatophytes - mainly trichophyton rubrum (90%)
Yeasts - e.g. candida
How do you investigate nail infections?
Nail clippings
Scrapings of the nail
How do you treat fungal nail infections?
Don’t treat if asymptomatic or if patient does not care
Confirm via microbiology before starting treatment but:
Oral terbinafine or itraconazole first line for dermatophyte infections
Candida - topical antifungals such as amorolfine
How do we treat impetigo?
Topical fusidic acid (3x a day for 5 days) + good hygiene measures
What are the clinical features of impetigo?
Non-bullous - thin walled vesicles or pustules with a characteristic golden/brown crust
Bullous - flaccid fluid vesicles with blisters. Can still have yellow/brown crust
What causes impetigo?
Staph aureus for both bullous and non-bullous
Strep pyogens can also be a cause of non-bullous
How long before returning to work with impetigo?
48 hours following commencement of treatment
How to treat extensive impetigo disease?
Flucloxacillin
Oral erthromycin if pen-allergic
What are normal ankle-brachial pressure indexes?
0.90-1.2
<0.9 indicates arterial disease
>1.2 also indicates arterial disease
0.5-0.9 may be associated with intermittent claudication
How do we treat venous ulceration?
Compression bandaging Oral pentoxifylline (a peripheral dilator)
What is erythema nodosum?
Inflammation of subcutaneous fat, often over shins but can also be on forearms, thighs etc.
Characteristics:
Tender, erythematous, nodular lesions
What are causes of erythema nodosum?
Infection - strep., TB, brucellosis Systemic disease such as sarcoidosis, IBD, Behcet's Malignancy/lymphoma Drugs Pregnancy
What is pyoderma gangrenosum associated with?
IBD Rheumatoid arthritis Myeloproliferative disorders Lymphoma/myeloid leukaemias PBC
What are the features of pyoderma gangrenosum?
Initially small red papule
Later deep, red, necrotic ulcers with a violaceous (violet) border
Systemic features such as fever, myalgia
Typically on lower limbs
How do we treat pyoderma gangrenosum?
Oral steroids first line
Other immunosuppressive therapy - e.g. ciclosporin
What is tinea pedis (athlete’s foot) caused by?
Fungi in the genus trichophyton
What are features of athlete’s foot?
Scaling, flaking and itching between the toes
How do we treat athlete’s foot?
Topical imidazole, undeconoate or terbinafine
What is vitiligo?
An autoimmune condition which results in the loss of melanocytes and subsequent depigmentation of the skin
What is vitiligo associated with?
Other autoimmune conditions, e.g. addison’s, type 1 DM, autoimmune thyroid disorders
How do we treat vitiligo?
Sunblock for affected areas of skin
Camouflage make-up
Topical corticosteroids may reverse changes if used early
What is molluscum contagiosum caused by?
Molluscum contagiosum virus
What are the features of molluscum contagiosum?
Pinkish/pearly white papules with a central umbilication
Lesions appear in clusters
What is the management for molluscum contagiosum?
Self-limiting (within 18 months)
They are contagious so avoid towel sharing etc.
What are the features of scabies?
Widespread pruritus
Linear burrows on the sides of fingers, interdigital webs and flexor aspects of wrists
In infants, face and scalp may be affected
What causes scabies?
Sarcoptes scabiei
How is scabies spread?
Prolonged skin contact
What type of hypersensitivity reaction do you get in scabies?
Type IV
How do we manage scabies?
Permethrin 5%
Malathion 0.5% 2nd line
Treat everyone in household at the same time regardless of symptoms
Launder/iron/tumble dry all clothing/bedding/towels on first day of treatment
What are the adverse effects of isotretinoin?
Teratogenicity Dry skin/eyes/mouth Low mood Raised triglycerides Hair thinning Nose bleeds
What are the features of acne rosacea?
Typically affects nose, cheeks and forehead
Flushing
Telangiectasia
Later develops persistent erythema with papuples/pustules
Rhinophyma
Blepharitis sometimes
How do we treat acne rosacea?
Topical metronidazole first line
Topical brimonide if flushiing but limited telangiectasia
Severe disease - systemic abx e.g. oxytetracycline
In what condition do you get a rhinophyma?
Acne rosacea
What are milia?
Small, benign, keratin-filled cysts typically found on the face
Exacerbating factors of psoriasis?
Trauma
Alcohol
Drugs: beta blockers, lithium, NSAIDs, ACEi and infliximab
Steroid withdrawal
How do we treat erythasma?
Erythromycin
What is dermatitis herpetiformis?
An autoimmune blistering skin disorder associated with coeliac’s.
It is caused by IgA deposition in the dermis
Features of dermatitis herpetiformis?
Itchy, vesicular lesions on extensor surfaces
How to manage dermatitis herpetiformis?
Gluten-free diet
Dapsone
What are the features of bullous pemphigoid?
Itchy, tense blisters typically around flexures
Mouth is usually spared
What would you see on skin biopsy in bullous pemphigoid?
Immunofluorescence would show IgG and C3 at the dermoepidermal junction
What is the management of bullous pemphigoid?
Refer to derm
Oral corticosteroids
Topical corticosteroids, immunosuppressants and abx
What is acanthosis nigricans?
Describes symmetrical brown, velvety plaques
Often found in neck, axilla and groin
What is pityriasis versicolor?
A superficial cutaneous fungal infection caused by Malassezia furfur
Features of pityriasis versicolor?
Most commonly affects the trunk
Patches may be hypopigmented, pink or brown
Scaliness is common
Mild pruritus
Treatment of pityriasis versicolor?
Topical antifungals (e.g. ketoconazole shampoo)
What is lentigo maligna?
A type of melanoma in-situ (confined to the tissue of origin). It progresses slowly but may eventually cause lentigo maligna melanoma
What is solar lentigo?
A harmless patch of darkened skin -
Due to sun exposure (UV) causing proliferation of melanocytes and accumulation of melanin within the cells
How do we treat lentigo maligna?
Refer to dermatology (probably for surgery)
What is seborrhoeic dermatitis?
Chronic dermatitis thought to be an inflammatory reaction to a normal skin inhabitant called malassezia furfur (a fungus)
Features of seborrhoeic dermatitis?
Eczematous lesions on sebum-rich areas: scalp (dandruff), periorbital, auricular and nasolabial folds
Otitis externa/blepharitis can occur
How do we manage seborrhoeic dermatitis?
Topical antifungal - ketoconazole
Head + shoulders shampoo for scalp (first line)
What is guttate psoriasis caused by?
It is often preceded by an URTI (usually strep throat)
How do we manage guttate psoriasis?
Usually resolves spontaneously within 2-3 months
There is no firm evidence to support abx use
Can use topical agents as per psoriasis (topical steroids, vit D, dithranol and tar preparations)
What are the features of guttate psoriasis?
‘Tear drop’ scaly papules on the trunk and limbs
How can you differentiate between guttate psoriasis and pityriasis rosea?
Pityriasis rosea:
- Less likely to have recent URTI
- ‘Herald patch’ (lone patch of redness) for 1-2 weeks before widespread symptoms
What is erythema multiforme?
It is a hypersensitivity reaction which is most commonly triggered by infections
What are the features of erythema multiforme?
Target lesions
Initially seen on the back of the hands/feet before spreading to the torso
Upper limbs are more commonly affected than lower limbs
Pruritus is occasionally seen and is usually mild
What are the causes of erythema multiforme?
Herpes simplex virus (most common)
Idiopathic
Mycoplasma, streptococcus
Drugs: penicillin, sulphonamides, carbamazepine, allopurinol, NSAIDs, OCP, nevirapiine
What is erythema multiforme major?
The most severe form, associated with mucosal involvement
How do we treat erythema multiforme?
Symptomatically Oral antihistamines Analgesics Local skin care Topical steroids can be considered
What is a pyogenic granuloma?
A relatively common benign skin lesion
What are the factors associated with pyogenic granuloma?
Trauma
Pregnancy
More common in women/young adults
What are the features of pyogenic granuloma?
Head/neck/upper trunk/hands Oral mucosa common in pregnancy Initially a small red/brown spot Rapidly progresses to form a raised red/brown lesion often spherical in shape Lesion can bleed/ulcerate
How do we treat pyogenic granuloma?
If associated with pregnancy, often resolve spontaneously post-partum
Removal via curettage, cauterisation, cryotherapy/excision
Which anti-fungal causes gynecomastia?
Ketoconazole
What is acanthosis nigricans associated with?
GI Cancer DM Obesity PCOS Acromegaly Cushing's Hypothyroidism Prader-willi OCP
What is a sebaceous cyst?
A term which emcompasses both epidermoid and pilar cysts
Features of a sebaceous cyst?
Typically contains a punctum and are often located on the scalp
What is hereditary haemorrhagic telangiectasia?
An autosomal domiinant condition characterised by multiple telangiectasia over the skin and mucous membranes
Diagnostic criteria of hereditary haemorrhagic telangiectasia?
Epistaxis (spontaneous/recurrent nosebleeds)
Telangiectases (lips, oral cavity, fingers and nose)
Visceral lesions
FHx
What is Bowen’s disease?
Bowen’s disease is a type of intraepidermal SCC
Features of Bowen’s disease?
Red, scaly patches
Often occur on sun-exposed areas (e.g. lower limbs)
How do we treat Bowen’s disease?
Topical 5-fluorouracil or imiquimod
Cryotherapy
Excision
How can you treat telangiectasia in acne rosacea?
Laser therapy
What type of hypersensitivity reaction is contact dermatitis?
Type IV
What are the features of lichen planus?
Itchy, papular, polygonal rash
‘White lines’ (Wickham’s striae)
How to treat lichen planus?
Topical steroids
Benzydamine mouthwash/spray for oral lichen planus
If extensive, oral steroids/immunosuppression
