Dermatology Flashcards
Acanthosis nigricans
Describes symmetrical, brown, velvety plaques that are often found on the neck, axilla and groin
Causes
gastrointestinal cancer
diabetes mellitus
obesity
polycystic ovarian syndrome
acromegaly
Cushing’s disease
hypothyroidism
familial
Prader-Willi syndrome
drugs: oral contraceptive pill, nicotinic acid
Acne Rosacea
Features
typically affects nose, cheeks and forehead
flushing is often first symptom
telangiectasia are common
later develops into persistent erythema with papules and pustules
rhinophyma
ocular involvement: blepharitis
sunlight may exacerbate symptoms/
Management
topical metronidazole may be used for mild symptoms (i.e. Limited number of papules and pustules, no plaques)
topical brimonidine gel may be considered for patients with predominant flushing but limited telangiectasia
more severe disease is treated with systemic antibiotics e.g. Oxytetracycline
recommend daily application of a high-factor sunscreen
camouflage creams may help conceal redness
laser therapy may be appropriate for patients with prominent telangiectasia
patients with a rhinophyma should be referred to dermatology
Acne
Acne vulgaris is a common skin disorder which usually occurs in adolescence. It typically affects the face, neck and upper trunk and is characterised by the obstruction of the pilosebaceous follicles with keratin plugs which results in comedones, inflammation and pustules.
A simple step-up management scheme often used in the treatment of acne is as follows:
single topical therapy (topical retinoids, benzoyl peroxide)
topical combination therapy (topical antibiotic, benzoyl peroxide, topical retinoid)
oral antibiotics:
tetracyclines: lymecycline, oxytetracycline, doxycycline
tetracyclines should be avoided in pregnant or breastfeeding women and in children younger than 12 years of age
erythromycin may be used in pregnancy
minocycline is now considered less appropriate due to the possibility of irreversible pigmentation
a single oral antibiotic for acne vulgaris should be used for a maximum of three months
a topical retinoid (if not contraindicated) or benzoyl peroxide should always be co-prescribed with oral antibiotics to reduce the risk of antibiotic resistance developing. Topical and oral antibiotics should not be used in combination
Gram-negative folliculitis may occur as a complication of long-term antibiotic use - high-dose oral trimethoprim is effective if this occurs
combined oral contraceptives (COCP) are an alternative to oral antibiotics in women
as with antibiotics, they should be used in combination with topical agents
Actinic keratoses
Actinic, or solar, keratoses (AK) is a common premalignant skin lesion that develops as a consequence of chronic sun exposure
Features
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
multiple lesions may be present
Management options include
prevention of further risk: e.g. sun avoidance, sun cream
fluorouracil cream: typically a 2 to 3 week course. The skin will become red and inflamed - sometimes topical hydrocortisone is given following fluorouracil to help settle the inflammation
topical diclofenac: may be used for mild AKs. Moderate efficacy but much fewer side-effects
topical imiquimod: trials have shown good efficacy
cryotherapy
curettage and cautery
Alopecia
Alopecia may be divided into scarring (destruction of hair follicle) and non-scarring (preservation of hair follicle)
Scarring alopecia
trauma, burns
radiotherapy
lichen planus
discoid lupus
tinea capitis*
Non-scarring alopecia
male-pattern baldness
drugs: cytotoxic drugs, carbimazole, heparin, oral contraceptive pill, colchicine
nutritional: iron and zinc deficiency
autoimmune: alopecia areata
telogen effluvium
hair loss following stressful period e.g. surgery
trichotillomania
Anti-histamines
Loratadine and cetirizine are non-sedating antihistamines meaning they are less sedating than alternatives such as chlorpheniramine
Important for meLess important
Loratadine is a non-sedating antihistamine - although it can cause sedation it is less likely to do so than other medications.
Chlorphenamine and promethazine are both useful antihistamines but are more likely to cause sedation than loratadine.
Buclizine is an antihistamine although it is more commonly used as an anti-emetic (in combination with paracetamol) for the relief of migraines.
Mirtazapine has antihistamine properties but is used primarily as an antidepressant and appetite stimulant.
Antihistamines (H1 inhibitors) are of value in the treatment of allergic rhinitis and urticaria.
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
Of the non-sedating antihistamines there is some evidence that cetirizine may cause more drowsiness than other drugs in the class.
Basal cell carcinoma
Basal cell carcinoma (BCC) is one of the three main types of skin cancer. Lesions are also known as rodent ulcers and are characterised by slow-growth and local invasion. Metastases are extremely rare. BCC is the most common type of cancer in the Western world.
Features
many types of BCC are described. The most common type is nodular BCC, which is described here
sun-exposed sites, especially the head and neck account for the majority of lesions
initially a pearly, flesh-coloured papule with telangiectasia
may later ulcerate leaving a central ‘crater’
Referral
generally, if a BCC is suspected, a routine referral should be made
Management options:
surgical removal
curettage
cryotherapy
topical cream: imiquimod, fluorouracil
radiotherapy
Bullous disorders
Causes of skin bullae
congenital: epidermolysis bullosa
autoimmune: bullous pemphigoid, pemphigus
insect bite
trauma/friction
drugs: barbiturates, furosemide
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
Bullous pemphigoid is more common in elderly patients.
Features include
itchy, tense blisters typically around flexures
the blisters usually heal without scarring
mouth is usually spared*
Skin biopsy
immunofluorescence shows IgG and C3 at the dermoepidermal junction
Management
referral to dermatologist for biopsy and confirmation of diagnosis
oral corticosteroids are the mainstay of treatment
topical corticosteroids, immunosuppressants and antibiotics are also used
Burns pathology
Extensive burns
Haemolysis due to damage of erythrocytes by heat and microangiopathy
Loss of capillary membrane integrity causing plasma leakage into interstitial space
Extravasation of fluids from the burn site causing hypovolaemic shock (up to 48h after injury)- decreased blood volume and increased haematocrit
Protein loss
Secondary infection e.g. Staphylococcus aureus
ARDS
Risk of Curlings ulcer (acute peptic stress ulcers)
Danger of full thickness circumferential burns in an extremity as these may develop compartment syndrome
Eczema herpeticum
Eczema herpeticum describes a severe primary infection of the skin by herpes simplex virus 1 or 2.
It is more commonly seen in children with atopic eczema and often presents as a rapidly progressing painful rash.
On examination, monomorphic punched-out erosions (circular, depressed, ulcerated lesions) usually 1–3 mm in diameter are typically seen.
As it is potentially life-threatening children should be admitted for IV aciclovir.
Erythema multiforme
Erythema multiforme is a hypersensitivity reaction which is most commonly triggered by infections. It may be divided into 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 than the lower limbs
pruritus is occasionally seen and is usually mild
Causes
viruses: herpes simplex virus (the most common cause), Orf*
idiopathic
bacteria: Mycoplasma, Streptococcus
drugs: penicillin, sulphonamides, carbamazepine, allopurinol, NSAIDs, oral contraceptive pill, nevirapine
connective tissue disease e.g. Systemic lupus erythematosus
sarcoidosis
malignancy
Erythroderma
Erythroderma is a term used when more than 95% of the skin is involved in a rash of any kind.
Causes of erythroderma
eczema
psoriasis
drugs e.g. gold
lymphomas, leukaemias
idiopathic
Erythema nodosum
Overview
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
Causes
infection
streptococci
tuberculosis
brucellosis
systemic disease
sarcoidosis
inflammatory bowel disease
Behcet’s
malignancy/lymphoma
drugs
penicillins
sulphonamides
combined oral contraceptive pill
pregnancy
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
Investigation
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
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
Hereditary haemorrhagic telangiectasia
Also known as Osler-Weber-Rendu syndrome, hereditary haemorrhagic telangiectasia (HHT) is an autosomal dominant condition characterised by (as the name suggests) multiple telangiectasia over the skin and mucous membranes. Twenty percent of cases occur spontaneously without prior family history.
There are 4 main diagnostic criteria. If the patient has 2 then they are said to have a possible diagnosis of HHT. If they meet 3 or more of the criteria they are said to have a definite diagnosis of HHT:
epistaxis : spontaneous, recurrent nosebleeds
telangiectases: multiple at characteristic sites (lips, oral cavity, fingers, nose)
visceral lesions: for example gastrointestinal telangiectasia (with or without bleeding), pulmonary arteriovenous malformations (AVM), hepatic AVM, cerebral AVM, spinal AVM
family history: a first-degree relative with HHT
Hirsutism and hypertrichosis
Hirsutism is often used to describe androgen-dependent hair growth in women, with hypertrichosis being used for androgen-independent hair growth
Polycystic ovarian syndrome is the most common causes of hirsutism. Other causes include:
Cushing’s syndrome
congenital adrenal hyperplasia
androgen therapy
obesity: thought to be due to insulin resistance
adrenal tumour
androgen secreting ovarian tumour
drugs: phenytoin, corticosteroids
Causes of hypertrichosis
drugs: minoxidil, ciclosporin, diazoxide
congenital hypertrichosis lanuginosa, congenital hypertrichosis terminalis
porphyria cutanea tarda
anorexia nervosa
Management of hirsutism
advise weight loss if overweight
cosmetic techniques such as waxing/bleaching - not available on the NHS
consider using combined oral contraceptive pills such as co-cyprindiol (Dianette) or ethinylestradiol and drospirenone (Yasmin). Co-cyprindiol should not be used long-term due to the increased risk of venous thromboembolism
facial hirsutism: topical eflornithine - contraindicated in pregnancy and breast-feeding
Impetigo
Features
‘golden’, crusted skin lesions typically found around the mouth
very contagious
Management
Limited, localised disease
topical fusidic acid is first-line
topical retapamulin is used second-line if fusidic acid has been ineffective or is not tolerated
MRSA is not susceptible to either fusidic acid or retapamulin. Topical mupirocin (Bactroban) should, therefore, be used in this situation
Extensive disease
oral flucloxacillin
oral erythromycin if penicillin-allergic
children should be excluded from school until the lesions are crusted and healed or 48 hours after commencing antibiotic treatment
Retinoids Isotretinoin
Isotretinoin is an oral retinoid used in the treatment of severe acne. Two-thirds of patients have a long-term remission or cure following a course of oral isotretinoin.
Adverse effects
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*
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 planus
sclerosus: itchy white spots typically seen on the vulva of elderly women
Lichen
planus: purple, pruritic, papular, polygonal rash on flexor surfaces. Wickham’s striae over surface. Oral involvement common
Lichen planus is a skin disorder of unknown aetiology, most probably being immune-mediated.
Features
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
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
Livedo reticularis
Livedo reticularis describes an purplish, non-blanching, reticulated rash caused by obstruction of the capillaries resulting in swollen venules.
Causes
idiopathic (most common)
polyarteritis nodosa
systemic lupus erythematosus
cryoglobulinaemia
antiphospholipid syndrome
Ehlers-Danlos Syndrome
homocystinuria
Pityriasis versicolor
Pityriasis versicolor, also called tinea versicolor, is a superficial cutaneous fungal infection caused by Malassezia furfur (formerly termed Pityrosporum ovale)
Features
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
Predisposing factors
occurs in healthy individuals
immunosuppression
malnutrition
Cushing’s
Management
topical antifungal. NICE Clinical Knowledge Summaries advise ketoconazole shampoo as this is more cost effective for large areas
if failure to respond to topical treatment then consider alternative diagnoses (e.g. send scrapings to confirm the diagnosis) + oral itraconazole
Port wine stains
Port wine stains are a vascular birthmark that do not spontaneoulsy resolve
Important for meLess important
The correct answer here is port wine stain. These typically occur on the face as a purplish/red macule with irregular contours. They can be associated with intracranial vascular abnormalities like Sturge-Weber-Syndrome. They do not spontaneously resolve and can become darker or lumpy in later life. Treatment is with cosmetics or laser therapy.
Strawberry naevus or capillary haemangioma appear as a small red patch which develops in the first month of life, increasing in size until around 9 months and becoming more vascular. They are not present at birth and regress spontaneously.
Salmon patches or stork marks are pink telangiectatic macules present at birth and commonly found on the forehead or back of neck. They do not require treatment and often self-resolve. They are not associated with underlying conditions.
Mongolian blue spots are areas of bluish discolouration over the lower back and buttock which often disappear by 1 year of age. They should be documented and highlighted to parents as they can be mistake for bruising.
Melanocytic naevi are raised brown/black nodules which can be hairy and up to 20cm in diameter. There is a risk of developing melanomas from these and so they should be closely monitored.
Pruritis
Condition
Notes
Liver disease
History of alcohol excess
Stigmata of chronic liver disease: spider naevi, bruising, palmar erythema, gynaecomastia etc
Evidence of decompensation: ascites, jaundice, encephalopathy
Iron deficiency anaemia
Pallor
Other signs: koilonychia, atrophic glossitis, post-cricoid webs, angular stomatitis
Polycythaemia
Pruritus particularly after warm bath
‘Ruddy complexion’
Gout
Peptic ulcer disease
Chronic kidney disease
Lethargy & pallor
Oedema & weight gain
Hypertension
Lymphoma
Night sweats
Lymphadenopathy
Splenomegaly, hepatomegaly
Fatigue
Other causes:
hyper- and hypothyroidism
diabetes
pregnancy
‘senile’ pruritus
urticaria
skin disorders: eczema, scabies, psoriasis, pityriasis rosea
Psoriasis
management
NICE released guidelines in 2012 on the management of psoriasis and psoriatic arthropathy. Please see the link for more details.
Management of chronic plaque psoriasis
regular emollients may help to reduce scale loss and reduce pruritus
first-line: NICE recommend a potent corticosteroid applied once daily plus vitamin D analogue applied once daily (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 a vitamin D analogue 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
short-acting dithranol can also be used
Purpura
Children
- Meningococcal septicaemia
- Acute lymphoblastic leukaemia
- Congenital bleeding disorders
- Immune thrombocytopenic purpura
- Henoch-Schonlein purpura
- Non-accidental injury
Adults
- Immune thrombocytopenic purpura
- Bone marrow failure (secondary to leukaemias, myelodysplasia or bone metastases)
- Senile purpura
- Drugs (quinine, antiepileptics, antithrombotics)
- Nutritional deficiencies (vitamins B12, C and folate)
Pyoderma gangrenosum
Features
typically on the lower limbs
initially small red papule
later deep, red, necrotic ulcers with a violaceous border
may be accompanied systemic symptoms e.g. Fever, myalgia
Causes*
idiopathic in 50%
inflammatory bowel disease: ulcerative colitis, Crohn’s
rheumatoid arthritis, SLE
myeloproliferative disorders
lymphoma, myeloid leukaemias
monoclonal gammopathy (IgA)
primary biliary cirrhosis
Scabies
Features
widespread pruritus
linear burrows on the side of fingers, interdigital webs and flexor aspects of the wrist
in infants, the face and scalp may also be affected
secondary features are seen due to scratching: excoriation, infection
Management
permethrin 5% is first-line
malathion 0.5% is second-line
give appropriate guidance on use (see below)
pruritus persists for up to 4-6 weeks post eradication
Patient guidance on treatment (from Clinical Knowledge Summaries)
avoid close physical contact with others until treatment is complete
all household and close physical contacts should be 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.
The BNF advises to apply the insecticide to all areas, including the face and scalp, contrary to the manufacturer’s recommendation. Patients should be given the following instructions:
apply the insecticide cream or liquid to cool, dry skin
pay close attention to areas between fingers and toes, under nails, armpit area, creases of the skin such as at the wrist and elbow
allow to dry and leave on the skin for 8-12 hours for permethrin, or for 24 hours for malathion, before washing off
reapply if insecticide is removed during the treatment period, e.g. If wash hands, change nappy, etc
repeat treatment 7 days later
Shin lesions
The differential diagnosis of shin lesions includes the following conditions:
erythema nodosum
pretibial myxoedema
pyoderma gangrenosum
necrobiosis lipoidica diabeticorum
Below are the characteristic features:
Erythema 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)
Pretibial myxoedema
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
Soles of the feet
The table below gives characteristic exam question features for conditions affecting the soles of the feet
Diagnosis
Notes
Verrucas
Secondary to the human papilloma virus
Firm, hyperkeratotic lesions
Pinpoint petechiae centrally within the lesions
May coalesce with surrounding warts to form mosaic warts
Tinea pedis
More commonly called Athlete’s foot
Affected skin is moist, flaky and itchy
Corn and calluses
A corn is small areas of very thick skin secondary to a reactive hyperkeratosis
A callus is larger, broader and has a less well defined edge than a corn
Keratoderma
May be acquired or congenital
Describes a thickening of the skin of the palms and soles
Acquired causes include reactive arthritis (keratoderma blennorrhagica)
Pitted keratolysis
Affects people who sweat excessively
Patients may complain of damp and excessively smelly feet
Usually caused by Corynebacterium
Heel and forefoot may become white with clusters of punched-out pits
Palmoplantar pustulosis
Crops of sterile pustules affecting the palms and soles
The skin is thickened, red. Scaly and may crack
More common in smokers
Juvenile plantar dermatosis
Affects children. More common in atopic patients with a history of eczema
Soles become shiny and hard. Cracks may develop causing pain
Worse during the summer
Paraneoplastic syndromes associated with internal malignancies:
Skin disorder
Associated malignancies
Acanthosis nigricans -Gastric cancer
Acquired ichthyosis - Lymphoma
Acquired hypertrichosis lanuginosa -Gastrointestinal and lung cancer
Dermatomyositis - Ovarian and lung cancer
Erythema gyratum repens - Lung cancer
Erythroderma - Lymphoma
Migratory thrombophlebitis - Pancreatic cancer
Necrolytic migratory erythema - Glucagonoma
Pyoderma gangrenosum (bullous and non-bullous forms) - Myeloproliferative disorders
Sweet’s syndrome - Haematological malignancy e.g. Myelodysplasia - tender, purple plaques
Tylosis - Oesophageal cancer
Skin type
Skin type is an important risk factor for skin cancer. Skin types may be classified according to Fitzpatrick classification:
I: Never tans, always burns (often red hair, freckles, and blue eyes)
II: Usually tans, always burns
III: Always tans, sometimes burns (usually dark hair and brown eyes)
IV: Always tans, rarely burns (olive skin)
V: Sunburn and tanning after extreme UV exposure (brown skin, e.g. Indian)
VI: Black skin (e.g. Afro-Caribbean), never tans, never burns
Squamous cell carcinoma of the skin
Squamous cell carcinoma is a common variant of skin cancer. Metastases are rare but may occur in 2-5% of patients.
Risk factors include:
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
Toxic epidermal necrolysis
Toxic epidermal necrolysis (TEN) is a potentially life-threatening skin disorder that is most commonly seen secondary to a drug reaction. In this condition the skin develops a scalded appearance over an extensive area. Some authors consider TEN to be the severe end of a spectrum of skin disorders which includes erythema multiforme and Stevens-Johnson syndrome
Features systemically unwell e.g. pyrexia, tachycardic positive Nikolsky’s sign: the epidermis separates with mild lateral pressure
Drugs known to induce TEN
phenytoin
sulphonamides
allopurinol
penicillins
carbamazepine
NSAIDs
Venous ulceration
Venous ulceration is typically seen above the medial malleolus
Investigations
ankle-brachial pressure index (ABPI) is important in non-healing ulcers to assess for poor arterial flow which could impair healing
a ‘normal’ ABPI may be regarded as between 0.9 - 1.2. Values below 0.9 indicate arterial disease. Interestingly, values above 1.3 may also indicate arterial disease, in the form of false-negative results secondary to arterial calcification (e.g. In diabetics)
Management
compression bandaging, usually four layer (only treatment shown to be of real benefit)
oral pentoxifylline, a peripheral vasodilator, improves healing rate
small evidence base supporting use of flavinoids
little evidence to suggest benefit from hydrocolloid dressings, topical growth factors, ultrasound therapy and intermittent pneumatic compression
Zinc deficiency
Features
perioral dermatitis: red, crusted lesions
acrodermatitis
alopecia
short stature
hypogonadism
hepatosplenomegaly
geophagia (ingesting clay/soil)
cognitive impairment
