Dermatology Flashcards
What is basal cell carcinoma?
Most common type of cancer in the Western world
Related to exposure to sunlight
Clinically presents as a pearly white papulo-nodule or firm plaque
What is the aetiology of basal cell carcinoma?
Repetitive and frequent sun exposure, as ultraviolet radiation induces DNA damage in keratinocytes
What are the characteristics of basal cell carcinomas?
Slow-growth and local invasion
Initially a pearly, flesh-coloured papule with telangiectasia
May later ulcerate leaving a central ‘crater’
What sites are usually affected in basal cell carcinomas?
Sun-exposed sites, especially the head and neck account for the majority of lesions
What are the appropriate investigations for basal cell carcinoma?
Generally, if a BCC is suspected, a routine referral should be made on the 2WW
Biopsy for dermatohistopathology:
(diagnosis of a cancer is histological)
What are some of the management options for basal cell carcinoma?
Surgical removal
Curettage
Cryotherapy
Topical cream: imiquimod, fluorouracil
Radiotherapy
What is a burns injury?
A very common injury predominantly to skin and superficial tissues caused by heat from hot liquids, flame or contact with hot objects
How is the severity of burns injuries assessed?
- Burn size (% of total body surface area)
- Depth ( first to fourth degree)
What symptoms and signs would be seen on physical examination for a burns injury?
Erythema
Dry/ wet and painful
Dry and lacking of physical sensation (insensate)
Cellulitis
If face affected- clouded cornea
What are the risk factors for burn injuries?
Young children
Age > 60 years
What are the investigations for burn injuries?
A to E approach
Assess carbon monoxide (ABG) and fluid loss (ABG, urinary catheter)
Chest x-ray and ECG
Bloods
Wound biopsy and histology
What is the management of burns injuries?
- Initial first aid as above
- Review referral criteria to ensure can be managed in primary care
- Superficial epidermal: symptomatic relief - analgesia, emollients etc
- Superficial dermal: cleanse wound, leave blister intact, non-adherent dressing, avoid topical creams, review in 24 hours
What is the immediate first aid management in burns injuries?
- Airway, breathing, circulation
- Burns caused by heat:
a. remove the person from the source
b. within 20 minutes of the injury irrigate the burn with cool (not iced) water for between 10 and 30 minutes
c. cover the burn using cling film, layered, rather than wrapped around a limb - Electrical burns: switch off power supply and remove the person from the source
- Chemical burns:
a. brush any powder off then irrigate with water
b. attempts to neutralise the chemical are not recommended
How do you assess the extent of a burn injury?
- 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% - Lund and Browder chart: the most accurate method
the palmar surface is roughly equivalent to 1% of total body surface area (TBSA). Not accurate for burns > 15% TBSA
How do you assess the depth of a burns injury?
- Superficial epidermal (first degree) = Red and painful, dry, no blisters
- Partial thickness (superficial dermal) (second degree) = Pale pink, painful, blistered. Slow capillary refill
- Partial thickness (deep dermal) (second degree) = Typically white but may have patches of non-blanching erythema. Reduced sensation, painful to deep pressure
- Full thickness (third degree) = White (‘waxy’)/brown (‘leathery’)/black in colour, no blisters, no pain
What is the criteria for referral to secondary care for a burns injury?
All deep dermal and full-thickness burns.
Superficial dermal burns of more than 3% TBSA in adults, or more than 2% TBSA in children
Superficial dermal burns involving the face, hands, feet, perineum, genitalia, or any flexure, or circumferential burns of the limbs, torso, or neck
Any inhalation injury
Any electrical or chemical burn injury
Suspicion of non-accidental injury
What is the pathophysiology of severe burns injuries?
- Local response with progressive tissue loss and release of inflammatory cytokines
- Systemically, there are cardiovascular effects resulting from fluid loss and sequestration of fluid into the third space
- There is a marked catabolic response
- Immunosupression is common with large burns and bacterial translocation from the gut lumen is a recognised event → Sepsis is a common cause of death following major burns.
What is the management of severe burn injuries?
The initial aim = stop the burning process and resuscitate the patient
- Airway:
Smoke inhalation can result in airway oedema
Early intubation should be considered e.g. if deep burns to the face or neck, blisters or oedema of the oropharynx, stridor etc - IV fluids will be required for adults with burns greater than 15% (10% for children) of TBSA = Parkland formula, half of the fluid is administered in the first 8 hours
- Urinary catheter should be inserted and analgesia should be given
- Complex burns, burns involving the hand, perineum and face and burns >10% in adults and >5% in children should be transferred to a burns unit, circumferential burns affecting a limb or severe torso burns impeding respiration may require escharotomy to divide the burnt tissue (improve ventilation)
What is the prognosis of a burns injury?
Conservative management is appropriate for superficial burns and mixed superficial burns that will heal in 2 weeks
More complex burns may require excision and skin grafting
What is the fluid resuscitation formula used for burns injuries?
Parkland formula:
1. (Crystalloid only e.g. Hartman’s solution/Ringers’ lactate)
2. Total fluid requirement in 24 hours =
4 ml x (total burn surface area (%)) x (body weight (kg))
3. 50% given in first 8 hours, then 50% given in next 16 hours
4. Resuscitation endpoint:Urine output of 0.5-1.0 ml/kg/hour in adults (increase rate of fluid to achieve this)
Points to note: Starting point of resuscitation is time of injury, deduct fluids already given
What is the indication for fluid replacement in burns injuries?
Indication = >15% total body area burns in adults (>10% children)
The main aim of resuscitation is to prevent the burn deepening
Most fluid is lost 24h after injury
First 8-12h fluid shifts from intravascular to interstitial fluid compartments
Therefore circulatory volume can be compromised
However fluid resuscitation causes more fluid into the interstitial compartment especially colloid (therefore avoided in first 8-24h)
What is candidiasis of the skin?
When Candida colonises on the skin causing an infection
Also known as cutaneous candidiasis
What is the aetiology of candidiasis of the skin?
Candida is a yeast-like fungus = part of the normal commensal flora of the human gastrointestinal tract and the vagina
NOT part of the normal skin flora, but there may be transient colonization of fingers or body folds
Most common species = Candida albicans, responsible for over half of candidal skin infections
Usually asymptomatic but where mucosal barriers are disrupted or if the host’s defences are lowered, it can cause infections
What is the epidemiology of candidiasis of the skin?
Common
Being at extreme ages is a risk factor due to immature or weakened immunity
What are the risk factors for candidiasis of the skin?
Immunocompromised (HIV infection, chemotherapy, immunosuppressive drugs)
Cancer or malnutrition
Recent or concurrent use of drugs that promote candidal growth (broad-spectrum antibiotics and inhaled/oral corticosteroids)
Diseases in which the barrier function of the skin is disturbed (psoriasis and seborrhoeic eczema)
Endocrine disorders: DM and Cushing’s syndrome
Iron deficiency anaemia
High-oestrogen contraceptive pill or pregnancy
Poor hygiene
Where does candidiasis of the skin usually affect?
More likely to occur where skin rubs on skin (such as between skin folds in an obese person) and where heat and moisture lead to maceration and inflammation
-Armpits
-Groin
-Between the fingers
-Under the breasts
What are the features of candidiasis of the skin?
Rash-often causes redness and intense itching (armpits, groin, fingers/nails, under breasts)
Blisters and pustules
Scales may accumulate, producing a white-yellow, curd-like substance over the infected area
Satellite lesions
If web spaces (toes/fingers) involved = marked maceration with a thick, horny layer is usually prominent
What are the appropriate investigations for candidiasis of the skin?
Ix not necessary
But can exclude a differential diagnosis or an underlying condition (e.g. diabetes or anaemia) in people with widespread or recurrent infection
Standard bacteriology swabs for microscopy and culture may be required if:
1. Secondary bacterial infection is suspected
2. Immunocompromised
3. Diagnosis is uncertain
What is the management of candidiasis of the skin?
- Topical imidazole antifungal e.g. clotrimazole, econazole nitrate, ketoconazole, or miconazole
- Topical terbinafine is an alternative (not in refractory candidiasis)
- Topical application of nystatin is also effective for candidiasis but it is ineffective against dermatophytosis
- Refractory candidiasis requires systemic treatment generally with a triazole such as fluconazole (oral)
What is vaginal candidiasis?
Thrush
80% of cases of Candida albicans
Majority of women will have no predisposing factors, others may have DM, pregnancy, HIV, recent Abx or steroids
Features : ‘cottage cheese’, non-offensive discharge, vulvitis: superficial dyspareunia, dysuria
Ix: high vaginal swab for M+C not routinely needed unless >4 per year
Rx: oral fluconazole 150 mg as a single dose first-line, clotrimazole 500 mg intravaginal pessary as a single dose if oral therapy is contraindicated
(avoid oral in pregnancy)
Recurrent: check compliance, M+C, induction (oral fluconazole every 3 days for 3 doses) and maintenance (oral fluconazole weekly for 6 months)
What is Cellulitis?
Inflammation of the skin and subcutaneous tissues, typically due to infection by Streptococcus pyogenes or Staphylcoccus aureus
What is cellulitis usually characterised by?
Erythema
Oedema
Warmth
Tenderness
Commonly occurs in an extremity
What are the features of cellulitis?
Commonly occurs on the shins
Erythema, pain, swelling
There may be some associated systemic upset such as fever
What are the risk factors for cellulitis?
Common
Skin break
Poor hygiene
Poor vascularisation of tissue (e.g. DM)
What are the appropriate investigations for cellulitis?
Diagnosis is clinical
No further investigations are required in primary care
Bloods and blood cultures may be requested if the patient is admitted and septicaemia is suspected
Consider taking a swab for microbiological testing only if the skin is broken and there is risk of infection by an uncommon pathogen
What is periorbital /orbital cellulitis?
Periorbital: Painful swollen red skin around eye/ swollen eyelids
Orbital cellulitis:
Painful or limited eye movements
*Visual impairment
Proptosis (protrusion of the eyeball)
Impaired acuity and eye movement
Test for relative afferent pupillary defect, visual acuity and colour vision
CT/ MRI = to assess posterior spread of infection
Refer to ophthalmology as an emergency → orbital decompression may be necessary
What classification is used to guide admission and management of cellulitis?
Eron Classification
I = no signs of systemic toxicity and the person has no uncontrolled co-morbidities
II = either systemically unwell or systemically well but with a co-morbidity (e.g. peripheral arterial disease, chronic venous insufficiency, or morbid obesity) which may complicate or delay resolution of infection
III = significant systemic upset such as acute confusion, tachycardia, tachypnoea, hypotension, or unstable co-morbidities that may interfere with a response to treatment, or a limb-threatening infection due to vascular compromise
IV = sepsis syndrome or a severe life-threatening infection such as necrotising fasciitis
When do you admit for IV antibiotics in cellulitis?
- Eron Class III or Class IV cellulitis
- Severe or rapidly deteriorating cellulitis (e.g. extensive areas of skin)
- Is very young (under 1 year of age) or frail
- Is immunocompromised
- Has significant lymphoedema
- Has facial cellulitis (unless very mild) or periorbital cellulitis
(Eron class II can also be given IV antibiotics in the community if available- otherwise oral)
What is the management of cellulitis?
First line = flucloxacillin for mild/moderate cellulitis (BNF)
Clarithromycin, erythromycin (in pregnancy) or doxycyline is recommended in patients allergic to penicillin
Severe cellulitis should be offered co-amoxiclav, cefuroxime, clindamycin or ceftriaxone (NICE)
What is Erysipelas?
More superficial, limited version of cellulitis
Localised skin infection caused by Streptococcus pyogenes
What is the management of Erysipelas?
Oral flucloxacillin
What is eczema?
An inflammatory skin reaction to endogenous or exogenous agents characterised by dry, pruritic skin with a chronic relapsing course
What are the different types of eczema?
- Atopic (Hx of atopy)
- Contact (immune sensitisation e.g. nickel)
- Discoid (coin shaped usually affecting limbs)
- Dyshidrotic
- Herpeticum (medical emergency)
- Seborrhoeic (chronic, affecting face, scalp, ears and flexures due to reaction of yeasts that colonise skin)
What is the epidemiology of eczema?
Occurs in around 15-20% of children and is becoming more common.
Typically presents before 2 years but clears in:
- around 50% of children by 5 years of age
- 75% of children by 10 years of age
What are the presenting symptoms of eczema?
Itching (can be severe), heat, tenderness, redness, weeping, crusting
Enquire into occupational exposures or irritants used at home (e.g. bleach)
FH/ PH of atopy (e.g. asthma, hay fever, rhinitis)
What are the features of acute eczema?
- Poorly demarcated erythematous oedematous dry scaling patches
- Atopic: Particularly affects face and flexures (inside elbow and knee)
- Papules, vesicles with exudation and crusting
- Excoriation marks
What are the features of chronic eczema?
- Thickened epidermis
- Skin lichenification
- Fissures
- Change in pigmentation
- Seborrhoeic: Yellow greasy scales on erythematous plaques, particularly in the nasolabial folds, eyebrows, scalp and presternal area
What is eczema herpeticum?
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
What are the features of eczema herpeticum?
Monomorphic punched-out erosions (circular, depressed, ulcerated lesions) usually 1–3 mm in diameter are typically seen
What is the management of eczema herpeticum?
Potentially life-threatening
Children should be admitted for IV aciclovir
What are the investigations for eczema?
Clinical diagnosis usually
Contact dermatitis = offer skin patch testing to suspected allergens (positive if allergen induces a red raised lesion after 48 hrs)
Swab for infected lesions (bacteria, fungi and viruses)
What is the management of eczema?
Avoid irritants
Simple emollients (large quantities, 10:1 ratio with a topical steroid if prescribed)
Topical steroids
Wet wrapping (large amounts of emollient applied under wet bandages)
In severe cases, oral ciclosporin may be used
What are the considerations of simple emollients in the management of eczema?
- Large quantities should be prescribed (e.g. 250g / week), roughly in a ratio of with topical steroids of 10:1
- Apply emollient first followed by waiting at least 30 minutes before applying the topical steroid
- Creams soak into the skin faster than ointments
- Emollients can become contaminated with bacteria - fingers should not be inserted into pots (many brands have pump dispensers)
What is the steroid ladder used in eczema management?
Help Every Busy Dermatologist
1. Hydrocortisone 0.5-2.5% (mild)
2. Eumovate: Clobetasone butyrate 0.05% (moderate)
3. Betnovate: Betamethasone valerate 0.1% (potent)
4. Dermovate: Clobetasol propionate 0.05% (very potent)
What is the fingertip rule used for topical steroids in eczema management?
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 are epidermoid and pilar cysts (sebaceous cysts)?
Benign small bumps beneath the skin
Can appear anywhere on the skin, but are most common on the face, neck and trunk
Two of the most common types of cysts
What are the features of epidermoid and pilar cysts?
Small round bump under the skin
Have a central punctum
May contain small quantities of sebum
What is the difference between epidermoid and pilar cysts?
The cyst lining:
Epidermoid cyst = normal epidermis
Pilar cyst = outer root sheath of hair follicle
How is the diagnosis of an epidermoid or pilar cyst made?
Usually clinical
However, if suspicious the tissue can be excised and submitted for histology