Dermatology 1 Flashcards
What is your spot diagnosis for this patient?
Acanthosis nigricans
Acanthosis nigricans describes symmetrical, brown, velvety plaques that are often found on the neck, axilla and groin.
What is the pathophysiology?
insulin resistance → hyperinsulinemia → stimulation of keratinocytes and dermal fibroblast proliferation via interaction with insulin-like growth factor receptor-1 (IGFR1)
What may cause acanthosis nigricans?
obesity, T2DM
gastrointestinal cancer
PCOS
acromegaly
Cushing’s disease
hypothyroidism
Prader-Willi syndrome
drugs e.g. COCP
Acne is a common skin condition that involves inflammation of the pilosebaceous unit and is more common in adolescents.
What is the pathophysiology?
Multifactorial:
follicular epidermal hyperproliferation→ keratin plug → obstruction of the pilosebaceous follicle
colonisation by Propionibacterium acnes (anaerobic bacteria)
inflammation
How may acne be classified?
mild: open and closed comedones with or without sparse inflammatory lesions
moderate acne: widespread non-inflammatory lesions and numerous papules and pustules
severe acne: extensive inflammatory lesions, which may include nodules, pitting, and scarring
How should mild-moderate acne be managed?
a 12-week course of topical combination therapy should be tried first-line:
topical adapalene with topical benzoyl peroxide
topical benzoyl peroxide with topical clindamycin
topical tretinoin with topical clindamycin
topical benzoyl peroxide may be used as monotherapy if the person wishes to avoid using a topical retinoid or an antibiotic
How should moderate to severe acne be managed?
a 12-week course of one of the following options:
topical adapalene with topical benzoyl peroxide
topical adapalene with topical benzoyl peroxide + either oral lymecycline or oral doxycycline
topical tretinoin with topical clindamycin
COCP
Oral isotretinoin (secondary care)
What are the potential side effects of isotretinoin?
Dry skin and lips
Photosensitivity of the skin to sunlight
Depression, anxiety, aggression and suicidal ideation
Patients should be screened for mental health issues prior to starting treatment
Rarely Stevens-Johnson syndrome and toxic epidermal necrolysis
Which acne treatments are contraindicated in pregnancy?
tetracyclines (give erythromycin instead)
topical and oral retinoid treatment
What are the important points to remember about oral abx prescribing for acne?
Topical and oral antibiotics should not be used in combination
a topical retinoid or benzoyl peroxide should always be co-prescribed with oral antibiotics to reduce the risk of antibiotic resistance developing
only continue a tx option that includes abx for > 6 months in exceptional circumstances
tetracyclines should be avoided in pregnant/ breastfeeding women (use erythromycin instead) and in children <12
Which patients with acne should be referred to dermatology?
patients with acne conglobate acne: a rare and severe form of acne found mostly in men that presents with extensive inflammatory papules, suppurative nodules and cysts on the trunk
patients with nodulo-cystic acne
consider for patients with scarring and pigmentary changes
What are the possible complications associated with acne?
Gram-negative folliculitis: may occur as a complication of long-term antibiotic use for acne - give high-dose oral trimethoprim
Scarring
Progression to acne fulminans (emergency)
Psychological complications and social withdrawal
What type of scars may be caused by acne?
Ice pick scars : small indentations in the skin that remain after acne lesions heal
Hypertrophic scars: small lumps in the skin that remain after acne lesions heal
Rolling scars: irregular wave-like irregularities of the skin that remain after acne lesions heal
What is acne fulminans?
very severe acne associated with systemic upset (e.g. fever)
Hospital admission is often required and the condition usually responds to oral steroids
What is your spot diagnosis?
Actinic keratoses
Actinic keratoses is a common premalignant skin lesion that develops as a consequence of chronic sun exposure.
Describe the key features of these lesions
small, crusty or scaly, lesions
may be pink, red, brown or the same colour as the skin
typically on sun-exposed areas e.g. temples of head
How may actinic keratoses be managed?
prevention of further risk: e.g. sun avoidance, sun cream
fluorouracil cream: 2 to 3 week course
skin will become red and inflamed - sometimes topical hydrocortisone is given following fluorouracil to help settle the inflammation
cryotherapy
curettage and cautery
What is your spot diagnosis?
Alopecia areata
Alopecia areata is a presumed autoimmune condition causing hair loss.
Describe the pattern of hair loss seen
localised, well demarcated patches of hair loss
at the edge of the hair loss, there may be small, broken ‘exclamation mark’ hairs
How may alopecia areata be managed?
Hair will regrow in 50% of patients by 1 year, and in 80-90% eventually.
Other than reassurance, treatment options include:
topical or intralesional corticosteroids
topical minoxidil
phototherapy
dithranol
contact immunotherapy
wigs
Antihistamines (H1 inhibitors) are of value in the treatment of allergic rhinitis and urticaria.
Give some examples of sedating and non sedating anti-histamines.
Examples of sedating antihistamines:
chlorpheniramine
As well as being sedating these antihistamines have some antimuscarinic properties (e.g. urinary retention, dry mouth).
Examples of non-sedating antihistamines:
loratidine
cetirizine
What is your spot diagnosis?
Athlete’s foot - tinea pedis
Athlete’s foot (tinea pedis) is caused by which organism?
How does it present?
How may it be managed?
Trichophyton fungi
scaling, flaking, and itching between the toes
topical imidazole or terbinafine first-line
What is your spot diagnosis?
basal cell carcinoma - BCC
BCC is one of the 3 main types of skin cancer.
What are its main features?
mostly found on sun-exposed sites e.g. H+N
initially a pearly, flesh-coloured papule with telangiectasia
may later ulcerate leaving a central ‘crater’
What are the risk factors for developing a BCC?
Family hx
Increasing age
Male sex
Exposure to UV radiation, esp. in childhood
Fitzpatrick skin types I and II
Immunosuppression
Arsenic exposure
How may BCC be managed?
if a BCC is suspected, a routine referral should be made
Management options:
surgical removal
curettage
cryotherapy
topical cream: imiquimod, fluorouracil
radiotherapy
What are the standard surgical excision margins for a BCC?
4-5mm
What factors suggest increased risk of recurrence of BCC?
Tumour site (lesions on the central face)
Increasing tumour size
Poorly defined clinical margins
Histological features of aggression (perineural and ⁄ or perivascular involvement)
Failure of previous treatment
Immunosuppression
What is your spot diagnosis?
Bowen’s disease
What is Bowen’s disease?
a type of precancerous dermatosis that is a precursor to SCC
more common in elderly patients
5-10% chance of developing invasive skin cancer if left untreated
What are the key features of Bowen’s disease lesions?
red, scaly patches
often 10-15 mm in size
slow-growing
often occur on sun-exposed areas such as the head (e.g. temples) and neck, lower limbs
How can Bowen’s disease be managed?
topical 5-fluorouracil:
BD for 4 weeks
often results in significant inflammation/erythema
Topical steroids are often given to control this
cryotherapy
excision
What is your spot diagnosis?
Bullous pemphigoid
an autoimmune condition causing sub-epidermal blistering of the skin
Bullous pemphigoid is more common in elderly patients.
Features include:
itchy, tense blisters typically around flexures
the blisters usually heal without scarring
there is stereotypically no mucosal involvement (i.e. the mouth is spared)
What will be seen on skin biopsy of bullous pemphigoid?
immunofluorescence shows IgG and C3 at the dermoepidermal junction
How is bullous pemphigoid managed?
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
What is your spot diagnosis?
cherry hemangioma
Cherry haemangiomas (Campbell de Morgan spots) are benign skin lesions which contain an abnormal proliferation of capillaries.
What are the key features of these lesions?
erythematous, papular lesions
typically 1-3 mm in size
non-blanching
not found on the mucous membranes
As they are benign no treatment is usually required
What are the 2 main types of contact dermatitis?
Irritant contact dermatitis: COMMON
non-allergic reaction due to weak acids or alkalis (e.g. detergents)
Often seen on the hands
Erythema is typical, crusting and vesicles are rare
Allergic contact dermatitis: UNCOMMON
type IV hypersensitivity reaction
seen on the head following hair dyes, acute weeping eczema which predominately affects the margins of the hairline
Topical treatment with a potent steroid is indicated
How can irritant contact dermatitis be managed?
avoid the trigger
emollients
topical corticosteroids
What is your spot diagnosis?
Dermatitis herpetiformis
autoimmune condition associated with coeliac disease
Dermatitis herpetiformis is an autoimmune blistering skin disorder associated with coeliac disease.
What is it caused by?
What are its key features?
How can it be investigated?
deposition of IgA in the dermis
itchy, vesicular skin lesions on the extensor surfaces (e.g. elbows, knees, buttocks)
skin biopsy: direct immunofluorescence shows deposition of IgA in a granular pattern in the upper dermis
How may dermatitis herpetiformis be managed?
dapsone
gluten free diet
What is your spot diagnosis?
Dermatofibroma
Dermatofibromas (also known as histiocytomas) are common benign fibrous skin lesions.
What are they caused by?
What features do they present with?
They are caused by the abnormal growth of dermal dendritic histiocyte cells, often following a precipitating injury.
Features:
solitary firm papule or nodule, typically on a limb
typically around 5-10mm in size
overlying skin dimples on pinching the lesion
What is your spot diagnosis?
Eczema herpeticum
What is eczema herpeticum?
severe primary infection of the skin by HSV 1 or 2
presents as a rapidly progressing painful rash, most commonly in children with atopic eczema
How does eczema herpectium present on examination?
How should it be managed?
OE: monomorphic punched-out erosions usually 1-3 mm in diameter
lymphadenopathy
systemic symptoms such as fever, lethargy, irritability and reduced oral intake
viral swabs, admission for IV aciclovir
What is your spot diagnosis?
Atopic eczema
What is atopic eczema?
How does it present?
a chronic atopic condition caused by defects in the normal continuity of the skin barrier, leading to inflammation in the skin
dry, red, itchy and sore patches of skin over the flexor surfaces (the inside of elbows and knees) and on the face and neck
How can atopic eczema be managed?
Maintenance:
avoiding allergens and irritants
soap substitutes
emollients
Flares:
thicker emollients
topical steroids
“wet wraps”
antihistamines if very itchy
treating any bacterial infections
What is the finger tip rule for steroid tx of eczema?
1 finger tip unit (FTU) = 0.5 g, sufficient to treat a skin area about twice that of the flat of an adult hand
What is your spot diagnosis?
Erythema ab igne
What is erythema ab igne?
a skin disorder caused by over exposure to infrared radiation
characteristic features include reticulated, erythematous patches with hyperpigmentation and telangiectasia
classic hx = elderly lady who sits by open fire, hot water bottle placed directly on skin e.g. for cramps
What is your spot diagnosis?
Erythema multiforme
What is erythema multiforme?
What features may it present with?
a hypersensitivity reaction that is most commonly triggered by infections
minor and major forms
Features:
target lesions
initially seen on the back of the hands / feet before spreading to the torso
upper limbs are more commonly affected
pruritus is occasionally seen and is usually mild
What may cause erythema multiforme?
idiopathic
viruses: herpes simplex virus (most common cause) , mycoplasma pneumoniae
bacteria: Mycoplasma, Streptococcus
drugs: penicillin, sulphonamides, carbamazepine, allopurinol, NSAIDs, COCP
connective tissue disease e.g. SLE
sarcoidosis
malignancy
How may erythema mutiforme be managed?
clear underlying cause, for example a recent coldsore or treatment with penicillin = managed supportively
no clear underlying cause = further investigations e.g. CXR to look for mycoplasma pneumonia
major form = IV fluids, analgesia and steroids
What is your spot diagnosis?
Erythema multiforme major
What is erythema multiforme major?
more severe form of erythema multiforme, associated with mucosal involvement
What is your spot diagnosis?
Erythema nodosum
What is erythema nodosum?
inflammation of subcutaneous fat
typically causes tender, erythematous, nodular lesions
usually occurs over shins, may also occur elsewhere (e.g. forearms, thighs)
usually resolves within 6 weeks
lesions heal without scarring
Give some common causes of erythema nodosum
NODOSUM
Normal (idiopathic)
Oncology (malignancy)
Drugs (e.g. penicllin)
Oral Contraceptives
Sarcoidosis
Ulcerative colitis/Crohns
Microbiology - Tb, Viral, Bacterial, Fungal
What investigations would you do to look for the underlying cause of erythema nodosum?
Inflammatory markers (CRP and ESR)
Throat swab for streptococcal infection
Chest xray for mycoplasma, TB , sarcoidosis and lymphoma
Stool microscopy and culture for campylobacter and salmonella
Faecal calprotectin for inflammatory bowel disease
How is erythema nodosum generally managed?
managed conservatively with rest and analgesia and treating the underlying cause
Steroids may be used to help settle the inflammation
Most cases will fully resolve within 6 weeks
What is your spot diagnosis?
Erythroderma (also known as exfoliative dermatitis)
What is erythroderma?
when more than 95% of the skin is involved in a rash of any kind
Causes of erythroderma:
eczema
psoriasis
lymphomas, leukaemias
idiopathic
drugs
How can erythroderma be managed?
hospitalisation may be required for patients with severe erythroderma due to the risk of complications such as dehydration, temperature dysregulation, and sepsis
withdrawal of any offending drugs
consider high dose systemic steroids if underlying skin condition
What is your spot diagnosis?
What are the most common causative organisms?
fungal nail infection - thickened, rough, opaque nails are the most common finding
dermatophytes: 90% of cases
mainly Trichophyton rubrum
yeasts: 10% of cases
e.g. Candida
What are the risk factors for developing fungal nail infections?
increasing age
diabetes mellitus
psoriasis
repeated nail trauma
What is your spot diagnosis?
Guttate psoriasis
Guttate psoriasis is more common in children and adolescents.
What can trigger it?
What features does it present with?
may be precipitated by a streptococcal infection 2-4 weeks prior to the lesions appearing
Features
tear drop papules on the trunk and limbs
tends to be acute onset over days
How may guttate psoriasis be managed?
most cases resolve spontaneously within 2-3 months
there is no firm evidence to support the use of antibiotics to eradicate streptococcal infection
tonsillectomy may be necessary with recurrent episodes
topical agents as per psoriasis, UVB phototherapy
What is your spot diagnosis?
Hidradenitis suppurativa - also known as acne invertus
Hidradenitis suppurativa (HS) is a chronic, painful, inflammatory skin disorder.
What are the risk factors for developing it?
Family history
Smoking
Obesity, diabetes, PCOS
Mechanical stretching of skin
How does Hidradenitis suppurativa (HS) present?
recurrent, painful, and inflamed nodules
occurs most commonly on intertriginous skin
axilla is the most common site
nodules may rupture = smelly purulent discharge
coalescence of nodules = plaques, sinus tracts and ‘rope-like’ scarring
How can HS be managed?
Encourage good hygiene and loose-fitting clothing
Smoking cessation
Weight loss in obese
Acute flares can be treated with steroids or flucloxacillin
Long-term disease can be treated with topical or oral
antibiotics
Surgical incision and drainage may be needed in some cases
What are the potential complications of HS?
Sinus tracts, fistulas
Comedones
Scarring - severe scarring can lead to dense, rope-like bands in the skin with strictures and lymphedema
Contractures
Lymphatic obstruction
DDx for HS?
Acne vulgaris - primarily occurs on the face, upper chest, and back, whereas HS primarily involves intertriginous areas
Follicular pyodermas (folliculitis, furuncles, carbuncles) - Unlike HS, follicular pyodermas are transient and respond rapidly to antibiotics
Granuloma inguinale (donovanosis) - STI caused by Klebsiella granulomatis. Suspect donovanosis if there is an enlarging ulcer that bleeds in the inguinal area
What is the most common cause of hirsutism?
PCOS
Other causes:
Cushing’s syndrome
congenital adrenal hyperplasia
androgen therapy
obesity: thought to be due to insulin resistance
How can hirsutism be managed?
advise weight loss if overweight
cosmetic techniques such as waxing/bleaching - not available on the NHS
consider using COCP such as Yasmin
facial hirsutism: topical eflornithine - contraindicated in pregnancy and breast-feeding
What is your spot diagnosis?
impetigo
Describe non-bullous impetigo. How should it be managed?
typically occurs around the nose or mouth. The exudate from the lesions dries to form a “golden crust”. They do not usually cause systemic symptoms or make the person unwell.
antiseptic cream (hydrogen peroxide 1% cream)
topical fusidic acid
Oral flucloxacillin is used to treat more widespread or severe impetigo
Describe bullous impetigo. How should it be managed?
always caused by staphylococcus aureus
1 – 2 cm fluid filled vesicles form on the skin
exudate dries into golden crust
may be systemically unwell with fever
confirm dx with swabs, can manage with flucloxacillin
Keloid scars are tumour-like lesions that arise from the connective tissue of a scar and extend beyond the dimensions of the original wound.
What are the risk factors for developing these?
ethnicity: more common in people with dark skin
occur more commonly in young adults
common sites (in order of decreasing frequency): sternum, shoulder, neck, face, extensor surface of limbs, trunk
How can keloid scars be managed?
early keloids may be treated with intra-lesional steroids e.g. triamcinolone
excision is sometimes required but careful consideration needs to given to the potential to create further keloid scarring
What is your spot diagnosis?
How should this be managed?
Keratoacanthoma
a benign epithelial tumour, more common with advancing age
will often spontaneously regress within 3 months, but should be urgently excised to exclude SCC
What is your spot diagnosis?
Leukoplakia - a premalignant condition
What is your spot diagnosis?
Squamous Cell Carcinoma
Give some risk factors for developing SCC of the skin
excessive exposure to sunlight / psoralen UVA therapy
actinic keratoses and Bowen’s disease
immunosuppression e.g. following renal transplant, HIV
smoking
long-standing leg ulcers (Marjolin’s ulcer)
genetic conditions e.g. xeroderma pigmentosum, oculocutaneous albinism
What features may SCC present with?
typically on sun-exposed sites such as the head and neck or dorsum of the hands and arms
rapidly expanding painless, ulcerate nodules
may have a cauliflower-like appearance
there may be areas of bleeding
How can SCC be managed?
lesion <20mm in diameter: surgical excision with 4mm margins
tumour >20mm : surgical excisions with 6mm margins
Mohs micrographic surgery may be used in high-risk patients and in cosmetically important sites.
What factors confer poor prognosis of SCC?
Poorly differentiated tumours
>20mm in diameter
>4mm deep
Immunosupression for whatever reason
What is Stevens-Johnson syndrome?
a severe systemic reaction affecting the skin and mucosa that is almost always caused by a drug reaction
causes: PLANS
penicillin
lamotrigine, carbamazepine, phenytoin
allopurinol
NSAIDs
sulphonamides
What features does Stevens Johnson syndrome present with?
How would you manage a patient who presented like this?
the rash is typically maculopapular with target lesions
may develop into vesicles or bullae
Nikolsky sign is positive in erythematous areas - blisters and erosions appear when the skin is rubbed gently
mucosal involvement
systemic symptoms: fever, arthralgia
Mx: hospital admission for supportive care
