Dermatology Flashcards
causes of acanothis nigricans
- type 2 diabetes mellitus
- gastrointestinal cancer
- obesity
- polycystic ovarian syndrome
- acromegaly
- Cushing’s disease
- hypothyroidism
- Prader-Willi syndrome
- drugs
- combined oral contraceptive pill
- nicotinic acid
what is the common bacterium that causes acne
Propionibacterium acnes
what is the first-line management of acne
a single topical therapy containing a retinoid and benzoyl peroxide
what is the second-line treatment of acne vulgaris
- after trialling a topical treatment containing a retinoid and benzoyl peroxide
- try a combination therapy of a topical antibiotic, topical retinoid and benzoyl peroxide
what is the third line treatment for acne vulgaris
- if topical treatment containing antibiotic, retinoid and benzoyl peroxide doesn’t work then use:
- oral tetracycline such as doxycycline
- if pregnant: erythromycin
- COCP is an alternative
- both oral abx and COCP should be co-prescribed with a topical retinoid
- oral abx should be used for a maximum of months
if oral abx/COCP doesn’t work for acne what treatment should you start
- oral isotretinoin
- should only be prescribed under specialist supervision
- pregnancy is a contraindication so they must be on adequate contraception
what is a contraindication to topical or oral retinoid treatment
pregnancy
try oral erythromycin for months with topical benzoyl peroxide
what is actinic keratoses and what is the management
a common premalignant skin lesion that develops as a consequence of chronic sun exposure
treatment is a 2-3 weeks course of fluorouracil cream - this will cause inflammation that may require hydrocortisone to settle
what do you get at the edges of a lesion of alopecia
small, broken, ‘exclamation mark’ hairs
what is the prognosis of alopecia areata
Hair will regrow in 50% of patients by 1 year, and in 80-90% eventually
what is the treatment of alopecia areata
- since 50% will have their hair grow back in a year and 80% will have it grow back at some point, careful counselling is often all that is needed
- other treatment options include
- topical corticosteroids
- phototherapy
two examples of non-sedating antihistamines
- loratidine
- cetirizine
what is an example of a sedating antihistamine
- chlorpheniramine
apart from drowsiness, what other side effect do sedating antihistamines cause
antimuscarinic properties (e.g. urinary retention, dry mouth)
what is the treatment for athlete’s foot
topical imidazole
what is the most common type of cancer in the western world?
BCC
what are the features of BCC
- sun-exposed sites, especially the head and neck
- pearly, flesh-coloured papule with telangiectasia
- may later ulcerate leaving a central ‘crater’
what type of referral for BCC
routine since metastases are extremely rare
what is bowen’s disease and what is the management
- pre-cancerous skin condition that can lead to SCC
- typically in sun exposed areas on the elderly
- management is topical 5-fluorouracil
- twice daily for 4 weeks
- often results in significant inflammation/erythema. Topical hydrocortisone to control this
what is bullous pemphigoid
autoimmune condition resulting in sub-epidermal blistering
what is the management of bullous pemphigoid
- referral to a dermatologist for biopsy and confirmation of diagnosis
- oral corticosteroids are the mainstay of treatment
how do you assess the extent of a burn
- Wallace’s Rule of Nines: head + neck = 9%, each arm = 9%, each anterior part of leg = 9%, each posterior part of leg = 9%, anterior chest = 9%, posterior chest = 9%, anterior abdomen = 9%, posterior abdomen = 9%
what is dermatitis herpetiformis
autoimmune blistering skin disorder associated with coeliac disease. It is caused by deposition of IgA in the dermis.
what is a dermatofibroma
it is a common benign skin lesion
like a little bump
often follows skin injury
overlying skin dimples when pinched
what is eczema herpeticum
severe primary infection of the skin by herpes simplex virus 1 or 2
commonly seen in children with atopic eczema and often presents as a rapidly progressing painful rash.
what is the management for exzema herpeticum
potentially life-threatening children should be admitted for IV aciclovir.
what is the fingertip unit
the amount of steroid that is squeezed along the fingertip is enough to treat an area the size of two adult hands with fingers together
what is the fingertip unit
the amount of steroid that is squeezed along the fingertip is enough to treat an area the size of two adult hands with fingers together
name some causes of erythema multiforme
pregnancy
IBD
sarcoidosis
behcet’s
streptococcal infection
TB
what is the main causative organism of fungal nail infections
dermatophytes - mainly Trichophyton rubrum
what is the management of fungal nail infection
oral terbinafine
what is guttate psoriasis
more common in children and adolescents. It may be precipitated by a streptococcal infection 2-4 weeks prior to the lesions appearing
most commonly goes away on its own within 2-3 weeks
what is the most common cause of hirsutism
PCOS
how do you treat hyperhydrosis
topical aluminium chloride preparations
what are the two most common causative organisms in impetigo
Staphylcoccus aureus or Streptococcus pyogenes
what is the first line treatment for impetigo in people who are not systemically unwell or at high risk of complications
hydrogen peroxide 1% cream
how do you treat impetigo if it doesn’t respond to hydrogen peroxide 1% cream or if there is extensive disease
- topical fusidic acid
- Topical mupirocin if MRSA suspected
- if extensive disease or if they are at risk of severe complications
- oral flucloxacillin
- oral erythromycin if penicillin-allergic
what are the school exclusion rules with impetigo
- children should be excluded from school until the lesions are crusted and healed or 48 hours after commencing antibiotic treatment
what is leukoplakia
Leukoplakia is a premalignant condition which presents as white, hard spots on the mucous membranes of the mouth. It is more common in smokers.
Biopsies are usually performed to exclude alternative diagnoses such as squamous cell carcinoma and regular follow-up is required to exclude malignant transformation to squamous cell carcinoma, which occurs in around 1% of patients
what are the features of lichen planus
- lichen planus
- purple
- pruritic
- polygonal
- papular
- most common on the palms, soles, genitalia and flexor surfaces of arms
- if seen in mouth typically a white-lace pattern on the buccal mucosa
how do you treat lichen planus
topical steroids
what are the features of lichen sclerosus
- usually affects genetalia of elderly women
- white patches that may scar
- itch is prominent
- may result in pain during intercourse or urination
- there’s increased risk of vulval cancer
what is the treatment for lichen sclerosis
topical steroids and emollients
what is breslow depth
the invasion depth of a tumour
it is the single most important factor in determining prognosis of patients with malignant melanoma
what is the management for molloscum contagiosum
- Reassure people that molluscum contagiosum is a self-limiting condition.
- Spontaneous resolution usually occurs within 18 months
- school exclusion isn’t necessary
what is pellagra
- caused by nicotinic acid (niacin) deficiency. The classical features are the 5 D’s -
- dermatitis
- diarrhoea
- dementia
- death
- depression
which population is pemphigus vulgaris more common in
ashkenazi jews
what are the features of pemphigus vulgaris
- oral ulceration in 50-70% of patients
- skin blistering - flaccid, easily ruptured vesicles and bullae.
- Lesions are painful but not itchy.
- These may develop months after the initial mucosal symptoms.
- Nikolsky’s describes the spread of bullae following application of horizontal, tangential pressure to the skin
- acantholysis on biopsy
what is the management for pemphigus vulgaris
steroids
what virus is implicated in pityriasis rosea
herpes hominis virus 7
what are the features of pityriasis rosea
- a minority may give a history of a recent viral infection
- herald patch (usually on trunk)
- followed by erythematous, oval, scaly patches which follow a characteristic distribution with the longitudinal diameters of the oval lesions running parallel to the line of Langer. This may produce a ‘fir-tree’ appearance
what is the management of pityriasis rosea
- self-limiting - usually disappears after 6-12 weeks
what is pityriasis versicolor
also called tinea versicolor, is a superficial cutaneous fungal infection
what are the features of pityriasis versicolor
- most commonly affects trunk
- patches may be hypopigmented, pink or brown (hence versicolor). May be more noticeable following a suntan
- scale is common
- mild pruritus
who does pityriasis versicolor affect
- can affect healthy individuals but predisposing factors are:
- immunosuppression
- malnutrition
- Cushing’
what is the treatment for pityriasis versicolor
NICE Clinical Knowledge Summaries advise ketoconazole shampoo as this is more cost effective for large areas
what are the HLA types associated with psoriasis
HLA-B13, -B17, and -Cw6.
nail changes seen in psoriasis
- pitting
- onycholysis (separation of the nail from the nail bed)
- subungual hyperkeratosis
- loss of the nail
what things can trigger psoriasis to get worse
- trauma
- alcohol
- drugs: beta blockers, lithium, antimalarials (chloroquine and hydroxychloroquine), NSAIDs and ACE inhibitors, infliximab
- withdrawal of systemic steroids
what is guttate psoriasis
like psoriasis but with raised papules
often triggered by a streptococcal infection - if this keeps happening then they may benefit from tonsillectomy
it’s treated the same as psoriasis and there’s no evidence for abx
name 6 drugs that can make psoriasis worse
- nsaids
- infliximab
- antimalarials
- chloroquine
- hydroxychloroquine
- ace inhibitors
- lithium
- beta blockers
what is the management of chronic plaque psoriasis on the main body
- first-line: NICE recommend:
- a potent corticosteroid applied once daily plus vitamin D analogue (calcipotriol) applied once daily
- should be applied separately, one in the morning and the other in the evening)
- for up to 4 weeks as initial treatment
- second-line: if no improvement after 8 weeks then offer:
- calcipotriol twice daily
- third-line: if no improvement after 8-12 weeks then offer either:
- a potent corticosteroid applied twice daily for up to 4 weeks, or
- a coal tar preparation applied once or twice daily
- secondary care
- phototherapy
- methotrexate (particularly if associated joint disease)
management of psoriasis on the face, flexures or genitals
mild or moderate potency corticosteroid applied once or twice daily for a maximum of 2 weeks
examples of topical vitamin d analogues for psoriasis and some notes on them
- calcipotriol, calcitriol and tacalcitol
- adverse effects are uncommon
- unlike corticosteroids they may be used long-term
- unlike coal tar and dithranol they do not smell or stain
- they tend to reduce the scale and thickness of plaques but not the erythema
- they should be avoided in pregnancy
- the maximum weekly amount for adults is 100g
what is pyoderma gangrenosum
- rare, non-infectious, inflammatory disorder resulting in rapidly progressing ulcers
- It may affect any part of the skin, but the lower legs are the most common site
- can be idiopathic
- other causes include IBD, primary biliary cirrhosis, SLE, rheumatoid arthritis and haematological conditions
- the edge of the ulcer is often described as purple, violaceous and undermined.
- the ulcer itself may be deep and necrotic
what is the management of pyoderma gangrenosum
progression is rapid so oral steroids are first line
what is an example of a retinoid and what are some adverse effects
- isotretanoin
- teratogenicity
- females need two forms of contraception
- dry skin, eyes and lips/mouth
- the most common side-effect
- low mood
- raised triglycerides
- hair thinning
- nose bleeds (caused by dryness of the nasal mucosa)
- intracranial hypertension
- photosensitivity
what is the management of scabies
- permethrin 5% is first-line
- malathion 0.5% is second-line
- advise that pruritis persists for up to 4-6 weeks post eradication
advice for scabies treatment
- avoid close physical contact with others until treatment is complete
- all household and close physical contacts treated at the same time, even if asymptomatic
- launder, iron or tumble dry clothing, bedding, towels, etc., on the first day of treatment to kill off mites.
- apply all over body and scalp
- allow to dry and leave on the skin for 8-12 hours for permethrin, or for 24 hours for malathion, before washing off
- repeat treatment 7 days later
what is Norwegian scabies
- crusted (Norwegian) scabies is seen in the immunocompromised
- the crusted skin is teeming with organisms
- treatment is with Ivermectin
features of seborrheic dermatitis
- eczematous lesions on the sebum-rich areas: scalp (may cause dandruff), periorbital, auricular and nasolabial folds
- otitis externa and blepharitis may develop
which two conditions are associate with seborrheic dermatitis
HIV
Parkinson’s
management for seborhoeic dermatitis of the scalp
- over the counter preparations containing zinc pyrithione (‘Head & Shoulders’) and tar (‘Neutrogena T/Gel’) are first-line
- the preferred second-line agent is ketoconazole
treatment of seborrhoeic dermatitis of the face and body
- topical antifungals: e.g. ketoconazole
- topical steroids: best used for short periods
- difficult to treat - recurrences are common
what are seborrhoeic keratoses
- benign epidermal skin lesions seen in older people.
- large variation in colour from flesh to light-brown to black
- have a ‘stuck-on’ appearance
- keratotic plugs may be seen on the surface
what are the features of shingles
- prodromal period
- burning pain over the affected dermatome for 2-3 days
- around 20% of patients will experience fever, headache, lethargy
- rash
- initially erythematous, macular rash over the affected dermatome
- quickly becomes vesicular
- characteristically is well demarcated by the dermatome and does not cross the midline. However, some ‘bleeding’ into adjacent areas may be seen
two difficult presentations of shingles
- herpes zoster ophthalmicus (shingles affecting affecting the ocular division of the trigeminal nerve) is associated with a variety of ocular complications
- herpes zoster oticus (Ramsay Hunt syndrome): may result in ear lesions and facial paralysis
management of shingles
- remind patients they are potentially infectious
- may need to avoid pregnant women and the immunosuppressed until 5-7 days following onset
- analgesia
- paracetamol and NSAIDs are first-line
- if not responding then use of neuropathic agents (e.g. amitriptyline) can be considered
- antivirals
- antivirals within 72 hours for the majority of patients, unless the patient is < 50 years and has a ‘mild’ truncal rash associated with mild pain and no underlying risk factors
- one of the benefits of prescribing antivirals is a reduced incidence of post-herpetic neuralgia, particularly in older people
- aciclovir, famciclovir, or valaciclovir are recommended
what is the most common complication of shingles
- post-herpetic neuralgia
- more common in older patients
name three skin disorders seen in pregnancy
- atopic eruption of pregnancy
- polymorphic eruption of pregnancy
- pemphigoid gestationis
what is the most common skin disorder found in pregnancy and what is the treatment
Atopic eruption of pregnancy - no specific treatment required
what are the features of polymorphic eruption of pregnancy and what is the treatment
- pruritic condition associated with last trimester
- lesions often first appear in abdominal striae
- periumbilical region is often spared
- management depends on severity: emollients, mild potency topical steroids and oral steroids may be used
what are some features of pemphigoid gestationis and what is the treatment
- pruritic blistering lesions
- often develop in peri-umbilical region, later spreading to the trunk, back, buttocks and arms
- usually presents 2nd or 3rd trimester and is rarely seen in the first pregnancy
- oral corticosteroids are usually required
4 skin disorders associated with lupus
- photosensitive ‘butterfly’ rash (malar rash)
- nasolabial sparing
- discoid rash
- alopecia
- livedo reticularis: net-like rash
what is steven johnson syndrome
Stevens-Johnson syndrome is a severe systemic reaction affecting the skin and mucosa that is almost always caused by a drug reaction.
may develop into toxic epidermal necrolysis
what are the features of stephen johnson syndrome
- rash is typically maculopapular with target lesions being characteristic. May develop into vesicles or bullae
- mucosal involvement
- systemic symptoms: fever, arthralgia
require admission for supportive treatment
what are the three types of tinea
- tinea capitis - scalp
- tinea corporis - trunk, legs or arms
- tinea pedis - feet
what are some drugs that are typically the causative agents in SJS and toxic epidermal necrolysis
- phenytoin
- sulphonamides
- allopurinol
- penicillins
- carbamazepine
- NSAIDs
what are the features of urticaria
- pale, pink raised skin. Variously described as ‘hives’, ‘wheals’, ‘nettle rash’
- pruritic
what are the features of urticaria
- non-sedating antihistamines are first-line
- prednisolone is used for severe or resistent episodes
name two large vessel vasculitides
- temporal arteritis
- Takayasu’s arteritis
name two medium vessel vasculitides
- polyarteritis nodosa
- Kawasaki disease
name ANCA associated small vessel vasculitides
- granulomatosis with polyangiitis (Wegener’s granulomatosis)
- eosinophilic granulomatosis with polyangiitis (Churg-Strauss syndrome)
- microscopic polyangiitis
name two small vessel immune complex mediated vasculitides
- Henoch-Schonlein purpura
- Goodpasture’s syndrome (anti-glomerular basement membrane disease)
is arterial or venous ulceration typically seen above the medial malleolus
venous
what is the management of venous ulceration
- compression bandaging, usually four layer (only treatment shown to be of real benefit)
how do you grade pressure ulcers
- Grade 1:
- Non-blanchable erythema of intact skin. Discolouration of the skin, warmth, oedema, induration or hardness may also be used as indicators, particularly on individuals with darker skin
- Grade 2:
- Partial thickness skin loss
- presents as abrasion or blister
- Grade 3:
- Full thickness skin loss down to subcut tissue
- May extend to but not through fascia
- Grade 4:
- Extensive tissue destruction
- With or without full thickness skin loss
what is the scoring system you can use to assess someone’s risk of pressure ulcers and which features does it include
- waterlow score
- age
- sex
- bmi
- nutritional status
- recent weight loss
- anaemia
- mobility
- continence
- peripheral vascular disease
- smoking
- organ failure
which organism causes hot tub folliculitis
pseudomonas aeruginosa
what’s the posh name for head lice
pediculosis capitis
abx for impetigo
Topical hydrogen peroxide, oral flucloxacillin or erythromycin if widespread
abx for cellulitis
Flucloxacillin
(clarithromycin, erythromycin or doxycycline if penicillin-allergic)
abx for cellulitis near the eyes or the nose
Co-amoxiclav
(clarithromycin, + metronidazole if penicillin-allergic)
abx for an animal or human bite
Co-amoxiclav (doxycycline + metronidazole if penicillin-allergic)
abx for mastitis while breast feeding
Flucloxacillin
