Dermatology Flashcards
psoriasis
exacerbating factors
trauma
alcohol
drugs: beta blockers, lithium, antimalarials (chloroquine and hydroxychloroquine), NSAIDs and ACE inhibitors, infliximab
withdrawal of systemic steroids
Streptococcal infection may trigger guttate psoriasis.
what is stevens-johnson syndrome
severe systemic reaction affecting the skin and mucosa that is almost always caused by a drug reaction.
Causes of Steven-Johnson Syndrome
penicillin sulphonamides lamotrigine, carbamazepine, phenytoin allopurinol NSAIDs oral contraceptive pill
Features of Stevens-Johnston Syndrome
rash is typically maculopapular with target lesions being characteristic. May develop into vesicles or bullae
mucosal involvement
systemic symptoms: fever, arthralgia
Erythyma Nodosum
symmetrical, erythematous, tender, nodules which heal without scarring
most common causes are streptococcal infections, sarcoidosis, inflammatory bowel disease and drugs (penicillins, sulphonamides, oral contraceptive pill)
Pre-tibial myoxdema
symmetrical, erythematous lesions seen in Graves’ disease
shiny, orange peel skin
Pyoderma gangrenosum
initially small red papule
later deep, red, necrotic ulcers with a violaceous border
idiopathic in 50%, may also be seen in inflammatory bowel disease, connective tissue disorders and myeloproliferative disorders
Necrobiosis lipoidica diabeticorum
shiny, painless areas of yellow/red skin typically on the shin of diabetics
often associated with telangiectasia
Adverse effects of retinoids
teratogenicity
females should ideally be using two forms of contraception (e.g. Combined oral contraceptive pill and condoms)
dry skin, eyes and lips/mouth
the most common side-effect of isotretinoin
low mood
whilst this is a controversial topic, depression and other psychiatric problems are listed in the BNF
raised triglycerides
hair thinning
nose bleeds (caused by dryness of the nasal mucosa)
intracranial hypertension: isotretinoin treatment should not be combined with tetracyclines for this reason
photosensitivity
Lichen sclerosus
inflammatory condition which usually affects the genitalia and is more common in elderly females. Lichen sclerosus leads to atrophy of the epidermis with white plaques forming
Lichen sclerosis
features, management, F/u
Features
itch is prominent
The diagnosis is usually made on clinical grounds but a biopsy may be performed if atypical features are present*
Management
topical steroids and emollients
Follow-up:
increased risk of vulval cancer
Causes of fungal nail infections
Onychomycosis is fungal infection of the nails. This may be caused by
dermatophytes - mainly Trichophyton rubrum, accounts for 90% of cases
yeasts - such as Candida
non-dermatophyte moulds
Risk factors include for fungal nail infections include diabetes mellitus andincreasing age.
Features of fungal nail infections
‘unsightly’ nails are a common reason for presentation
thickened, rough, opaque nails are the most common finding
Differential diagnosis of fungal nail infections
psoriasis
repeated trauma
lichen planus
yellow nail syndrome
Investigations fungal nail infection
nail clippings
scrapings of the affected nail
the false-negative rate for cultures are around 30%, so repeat samples may need to be sent if the clinical suspicion is high
Management of fungal nail infections
do not need to be treated if it is asymptomatic and the patient is not bothered by the appearance
diagnosis should be confirmed by microbiology before starting treatment
dermatophyte infection:
oral terbinafine is currently recommended first-line with oral itraconazole as an alternative
6 weeks - 3 months therapy is needed for fingernail infections whilst toenails should be treated for 3 - 6 months
treatment is successful in around 50-80% of people
Candida infection:
mild disease should be treated with topical antifungals (e.g. Amorolfine) whilst more severe infections should be treated with oral itraconazole for a period of 12 weeks
if topical topical treatment is given treatment should be continued for 6 months for fingernails and 9-12 months for toenails
Large vessel vasculitides
temporal arteritis
Takayasu’s arteritis
Medium vessel vasculitides
polyarteritis nodosa
Kawasaki disease
small vessel vasculititides
ANCA associated
granulomatosis with polyangiitis (Wegener’s granulomatosis)
eosinophilic granulomatosis with polyangiitis (Churg-Strauss syndrome)
microscopic polyangiitis
small vessel vasculititides
immune complex small-vessel vasculitis
Henoch-Schonlein purpura
Goodpasture’s syndrome (anti-glomerular basement membrane disease)
cryoglobulinaemic vasculitis
hypocomplementemic urticarial vasculitis (anti-C1q vasculitis)
Lichen planus
itchy, papular rash most common on the palms, soles, genitalia and flexor surfaces of arms
rash often polygonal in shape, with a ‘white-lines’ pattern on the surface (Wickham’s striae)
Koebner phenomenon may be seen (new skin lesions appearing at the site of trauma)
oral involvement in around 50% of patients: typically a white-lace pattern on the buccal mucosa
nails: thinning of nail plate, longitudinal ridging
Lichenoid drug eruptions - causes:
gold
quinine
thiazides
Management of Lichen Planus
potent topical steroids are the mainstay of treatment
benzydamine mouthwash or spray is recommended for oral lichen planus
extensive lichen planus may require oral steroids or immunosuppression
What is Dermatitis Herpetiformis?
Dermatitis herpetiformis is an autoimmune blistering skin disorder associated with coeliac disease. It is caused by deposition of IgA in the dermis.
Features of Dermatitis Herpetiformis
itchy, vesicular skin lesions on the extensor surfaces (e.g. elbows, knees, buttocks)
Diagnosis of Dermatitis Herpetiformis
Skin biospy
Management of Dermatitis Herpetiformis
gluten-free diet
dapsone
What is bullous pemphigoid
Bullous pemphigoid is an autoimmune condition causing sub-epidermal blistering of the skin. This is secondary to the development of antibodies against hemidesmosomal proteins BP180 and BP230.
Features of Bullous pemphigoid
Bullous pemphigoid is more common in elderly patients. Features include
itchy, tense blisters typically around flexures
the blisters usually heal without scarring
there is usually no mucosal involvement (i.e. the mouth is spared)*
Skin biopsy
immunofluorescence shows IgG and C3 at the dermoepidermal junction
Management of Bullous Pemphigoid
referral to a dermatologist for biopsy and confirmation of diagnosis
oral corticosteroids are the mainstay of treatment
topical corticosteroids, immunosuppressants and antibiotics are also used
Pemphgoid vs pemphigus
Pemphigoid = skin only
Pemphigus = skin and mucosa
retinoid adverse effects (isotretinoin)
hair thinning, low mood, teratogenicity, dry skin/eyes/mouth, nose bleeds, intracranial hypertension, photosensitivity
Typical history of erythema multiforme
an adult with erythematous target lesions on the hands which later spread to the torso following a herpes simplex infection
Typical history of bullous pemphigoid
an elderly women develops itchy, tense blisters around the flexures. There is no mucosal involvement
what is acanthosis nigricans
Describes symmetrical, brown, velvety plaques that are often found on the neck, axilla and groin.
Porphyria cutanea tarda
Associated with hep C
blisters, onycholysis (painless detachment of the nail from the nail bed), hyperpigmentation and hypertrichosis.
Pompholyx (dyshidrotic) eczema
typically presents on the inside of the fingers, palms, toes rather than the dorsum of the hand or the face. Again it can cause blisters (and is relatively common)
Management of Impetigo - topical
topical fusidic acid
topical mupirocin should be used if fusidic acid resistance is suspected
MRSA is not susceptible to either fusidic acid or retapamulin. Topical mupirocin should, therefore, be used in this situation
Acanthosis nigricans
Describes symmetrical, brown, velvety plaques that are often found on the neck, axilla and groin.
insulin resistance → hyperinsulinemia → stimulation of keratinocytes and dermal fibroblast proliferation via interaction with insulin-like growth factor receptor-1 (IGFR1)
Associated with gastric adenocarcinoma
Causes of acanthosis nigricans
type 2 diabetes mellitus gastrointestinal cancer obesity polycystic ovarian syndrome acromegaly Cushing's disease hypothyroidism familial Prader-Willi syndrome drugs combined oral contraceptive pill nicotinic acid
Skin associations of gastric squamous cell carcinoma
Most associated with acrokeratosis paraneoplastica, in regards to cutaneous manifestations.
Features of Rosecea
nose, cheeks and forehead
flushing, erythema, telangiectasia → papules and pustules
Treatment of keloid scars
early keloids may be treated with intra-lesional steroids e.g. triamcinolone
excision is sometimes required
Treatment of keloid scars
early keloids may be treated with intra-lesional steroids e.g. triamcinolone
excision is sometimes required
Treatment of keloid scars
early keloids may be treated with intra-lesional steroids e.g. triamcinolone
excision is sometimes required
Treatment of keloid scars
early keloids may be treated with intra-lesional steroids e.g. triamcinolone
excision is sometimes required
Treatment of keloid scars
early keloids may be treated with intra-lesional steroids e.g. triamcinolone
excision is sometimes required
Treatment of keloid scars
early keloids may be treated with intra-lesional steroids e.g. triamcinolone
excision is sometimes required
Pompholyx eczema (also known as dyshidrotic dermatitis)
Common condition characterised by an intensely pruritic vesicular eruption on the palms and soles.
Triggers:
- humidity e.g. increased sweating
- irritants e.g. water, detergents, metals (nickel)
- lifestyle e.g. smoking
- drug use e.g. aspirin and COCP
- fungal infections
Causes of scarring alopecia
trauma, burns radiotherapy lichen planus discoid lupus tinea capitis*
