Dermatology Flashcards
What is ecthyma?
Secondary infection of eczema with staphylococcus aureus
Causes deeper ulcers with thick yellow/grey scabs
What causes bullous pemphigoid?
auto-antibodies against antigens between the dermis and epidermis
What conditions are pyoderma gangrenosum associated with?
Rheumatological conditions e.g. RA, Ulcerative colitis
How does pyoderma gangrenosum present?
Painful rash on lower leg
Purplish, indurated edges
Often start as erythema nodosum or a small pustule which rapidly deepens and widens
Which type of skin cancer causes only local invasion rather than distant metastasis?
Basal cell carcinoma
What is erythroderma?
DERM EMERGENCY
Redness >90% of the whole body Caused by: Drugs (NSAIDs, antibiotics, anticonvulsants, antimalarials) Eczema Psoriasis Pityriasis rubra pilaris
What are the main concerns in erythroderma?
Dehydration and hypotension- loss of fluid autoregulation
Infection- loss of protective barrier
Hypothermia- loss of thermoregulation
What are the management options for vitiligo?
Steroids
Phototherapy
What is eczema herpeticum?
Herpes simplex complication of eczema
Causes extensive crusted papules, punched-out blisters and erosions
Rash is painful and associated with fever and malaise
Derm emergency, especially if over eyelid- risk of blindness
How is eczema herpeticum managed?
Oral aciclovir 400–800 mg 5 times daily, or, if available, valaciclovir 1 g twice daily, for 10–14 days or until lesions heal. - same day dermatological review
Intravenous aciclovir is prescribed if the patient is too sick to take tablets, or if the infection is deteriorating despite treatment. If eye involvement, go straight to IV treatment.
What nail changes are associated with psoriasis?
Nail pitting Leukonychia Onycholysis Subungal hyperkeratosis Subungal haemorrhage
= collectively known as psoriatic onychodystrophy
Where does scabies commonly affect?
Between the fingers
Genitalia
Permethrin treatment
What conditions are erythema nodosum associated with?
IBD TB Strep throat infections Sarcoid Drugs
What bacterial superinfection causes a green hue to lesions?
Pseudomonas
Where are the most common sites to suffer eczema?
In children: face and extensor surfaces
In adults: flexor surfaces
What are potential complications of eczema?
Bacterial superinfection e.g. staph aureus and impetiginastion
Viral superinfection e.g. eczema herpeticum
Other atopic conditions
Interruption to quality of life
Which drugs commonly cause photosensitivity?
Tetracyclines: doxycycline, limecycline Ciprofloxacin Amiodarone Hydroxychloroquine Isotretinoin
How is eczema classically managed?
- Emollient treatment, non-bio washing detergens, avoiding perfumes and allergens
- Topical steroids
- Immunomodulators: topical tacrolimus
Addition of bandage occlusion and wraps - Phototherapy: 2-3x weekly sessions 6-8w
- Systemic immunosuppression
What counselling points are there for emollient use?
- Apply as regularly as possible
- Apply 30mins BEFORE steroids
- Apply in direction of hair growth
- Stay away from flames + be aware of clothing being flammable
- Be aware of slipping in the bath
What counselling points are there for steroid use?
- Only use as often as prescribed
- Only apply to affected areas and very thin layer
- Apply 30 mins after emollients
- 1 finger tip unit = Two palm sized areas
- Don’t use on areas of infection
- Wash hands after use
What is the steroid ladder?
- Hydrocortisone 0.1-2.5% (1% usually good place to start)
- Eumovate
- Betnovate
- Dermovate
How is bacterial superinfection of eczema usually treated?
Topical antimicrobials: fusidic acid, neomycin
Systemic antibiotics: flucloxacillin first line (or erythromycin if allergic)
What are potential complications of eczema herpeticum?
Blindness Herpes hepatitis Encephalitis Pneumonitis DIC death
What is the classic presentation of psoriasis?
Itchy, scaly, erythematous plaques on the extensor surfaces
Nail changes
Plaques may develop on scars/areas of minor trauma
May have family history
Improvement in sunlight
May have associated arthropathy
What is guttate psoriasis?
Small, red, teardrop-shaped lesions on the trunk and limbs
Common occurs following strep throat infection
Self-limiting and disappear within 3 months- no treatment required
What is general pustular psoriasis?
Uncommon condition, result of severe and unstable psoriasis
Acute, erythematous tender skin with sheets of monomorphic small vesicles
Pustules initially occur at the margins of plaques
EMERGENCY and often need ITU management
How is psoriasis managed?
- Topical emollients (less effective than in eczema) and soap substitutes e.g. coal tar shampoo
- Topical steroids: usually potent, 4-8w courses (ideally 4 week breaks between courses)
- Vitamin D analogues: calcipotriol
- Sulphur-based preparations
If treatment-resistant:
- Phototherapy <10 weeks
- Ciclosporin (max 1-2 years)
- Methotrexate
- Acitretin (works best in combo with PUVA)
- TNF inhibitors= infliximab
- Other biologics
What is the best prognostic indicator in melanoma?
Breslow Score
-> distance in mm from granular layer in the epidermis to the deepest level of invasion into the dermis
What is the treatment indicated in melanoma?
Urgent excision with 2mm margins
Biopsy of any palpable lymph nodes
If positive margins after excision, imiquimod treatment
Follow-up at 3m and 12m, regular skin checks and sun protection
What is the most common type of skin cancer?
Basal cell carcinoma
What are the risk factors for squamous cell carcinoma?
Sun exposure / UV from sunbeds Fair skin (low Fitzpatrick number) Smoking Immunosuppressants Chronic ulcers Xeroderma pigmentosum (genetic cause of extreme sun sensitivity)
How do SCCs usually present?
Indurated nodular lesions
Rolled edge and surface telangiectasia
Often have crusted/hyperkeratotic surfaces
May be painful and grow rapidly
Common sites include: face, scalp, backs of hands
Most common in >60s
How is SCC treated?
Surgical excision with margins: 6mm in high risk and 4mm in low risk
Moh’s micrographic surgery
Adjuvant radiotherapy
In low-risk lesions:
Curretage and cautery
Topical efudix - especially in actinic keratoses
What are treatment options for actinic keratoses?
Cryotherapy
5-FU cream / efudix / immiquimod topical treatments
If no response, biopsy to rule out invasive malignancy
What is Bowen’s disease?
SCC in situ, no dermal invasion
Well-defined erythematous patches with slight crusting
Pre-malignant lesions
Can be removed or treated the same as actinic keratoses
Which type of skin cancer is not associated with smoking?
Basal cell carcinoma
What are risk factors of BCC?
UV light exposure
Fitzpatrick skin types 1 and 2
Gorlin’s syndrome
Immunocompromise
How does BCC normally present?
Small nodule with a rolled edge, often have a central depression which can become ulcerated
May also have pearly-nodular appearance
How is BCC managed?
Surgical excision with margins
Moh’s micrographic surgery - best cosmetic outcomes
Radiotherapy
Cryotherapy and imiquimod also options
What must be present for a diagnosis of acne to be made?
Open and closed comedones
What are the features of acne?
Open (blackheads) or closed (whiteheads) comedones Inflammatory papules or pustules Nodules or cysts Scarring Changes in pigmentation Seborrhoea (oily skin)
What is the management algorithm for acne?
- Topical benzoyl peroxide
Topical adapalene
Topical antibiotics: clindamycin/erythromycin
Trial the above + combinations for at least 3 months
Change contraceptive/start contraceptive in girls with acne in combo with topical treatment
- Oral antibiotics: oxytetracycline / tetracycline / limecycline 3 month course
- Isotretinoin: Roaccutane, oral retinoid which reduces sebum secretion
Women need contraception due to teratogenicity
SE: severe dryness of the skin + mucous membranes, nose bleeds, joint plain, mood prob
What are the features of rosacea?
Facial flushing, persistent erythema, telangiectasia, inflammatory papules, oedema
Over time, skin can become rough/course
Worsened by alcohol and sunlight + heat/exercise/hot food and drink/spicy food/emotion
How is rosacea managed?
Conservative:
Sun protection, reduce alcohol consumption, avoid triggers
Medical:
Topical brimonidine for erythema- can reduce redness in 30 mins
Topical ivermectin
Topical metronidazole
Oral antibiotics: tetracycline, doxycycline, erythromycin (often in combination with topical ivermectin)
Surgical:
Laser ablation of telangiectasia
Intense pulsed light therapy
What is the difference between SJS and TEN?
SJS: skin detachment of <10% of the body surface area
TEN: detachment of >10% of the body surface area, large epidermal sheets
TEN with spots: detachment >30% of the BSA, widespread purpuric macules
SJS/TEN overlap = 10-30% detachment with purpuric macules
What are the causes of SJS/TEN?
Most commonly drugs
- Antibiotics (40%)
- Anti-epileptics: lamotrigine, carbamazepine, phenytoin, phenobarbital
- Allopurinol
- Anti-retroviral therapy
- NSAIDs
Can also be infective: mycoplasma, herpes, hepatitis, mumps
Immunisations
^ risk in immunodeficiency e.g. HIV
What are the symptoms of SJS/TEN?
Sudden spreading rash, often after initiation of new medication
Mucosal ulceration/erosion
Nikolsky’s sign: peeling of skin (indicates progression to TEN)
Painful skin, may have purpuric macules
Fever >39, fatigue
Sore throat
Myalgia
How is SJS/TEN diagnosed?
Generally a clinical diagnosis
Should take skin swabs + biopsy, blood cultures and other baseline bloods
What are the differentials for SJS/TEN?
Staphylococcal scalded skin Burn Erythema multiform Toxic shock syndrome Septic shock
How should SJS/TEN be managed?
Dermatological emergency
- A-E assessment
- Fluid and temperature support
- Stop causative agent
- VTE prophylaxis, nutrition (may need enteral feeding due to mucosal involvement)
- Non-adhesive dressings, topical antibacterials, emollients
- May need immunosuppression: ciclosporin, immunoglobulin
What are complications of SJS/TEN?
Dehydration Malnutrition Skin infection Loss of temperature regulation ARDS VTE and DIC Organ failure, GI ulceration and perforation Compartment syndrome Mucous membrane stricture
What are the causes of erythema multiforme?
Most commonly infections:
HSV = most common cause, usually HSV1
Mycoplasma = second-most common
Can also be caused by medication, but this is more likely to be an alternative diagnosis e.g. SJS
What are the clinical features of erythema multiforme?
No prodrome
Several to hundreds of skin lesions develop within 24 hours
First seen on the backs of hands and/or tops of feet and then spread down the limbs towards the trunk.
The upper limbs are more commonly affected than the lower. Palms and soles may be involved.
The face, neck and trunk are common sites.
There may be an associated mild itch or burning sensation.
The typical target lesion has a sharp margin, regular round shape and three concentric colour zones:
- The centre is dusky or dark red with a blister or crust
- Next ring is a paler pink and is raised due to oedema (fluid swelling)
- The outermost ring is bright red.
Mucosal lesions may develop a few days later
How is erythema multiforme managed?
Treatment of underlying infection
Topical steroids
Eye and mouth care
Nutritional and fluid support
Which conditions are most strongly associated with pyoderma gangrenosum?
IBD (UC more commonly than Crohn’s)
Rheumatoid arthritis
Blood cancers
GPA
How does pyoderma gangrenosum present?
At the site of a minor injury/small wound
Skin breakdown and rapid ulceration
Blue/purple margins
Extremely painful rash
How is pyoderma gangrenosum managed?
Removal of any necrotic tissue
Topical steroid/tacrolimus/steroid injection into edge
Special dressings and compression bandages
Oral doxycycline
Systemic immunomodulation for more extensive disease
What is a pyogenic granuloma?
Reactive proliferation of capillaries- completely benign
Looks like a raspberry/mincemeat lesion stuck onto the skin
Most common on the hands and can bleed a lot
More common in pregnancy
Usually go away on their own but can be removed for cosmetic purposes
What are risk factors for alopecia areata?
Thyroid disease, vitiligo, atopic eczema
Chromosome disorders e.g. Down’s
Family history
Biologic medications
What are the features of alopecia areata
Patches of non-scarring alopecia- exclamation mark hairs or complete baldness
Cycling stages of hair loss, bald patch enlargement and regrowth
May also have nail disease
How is alopecia areata managed?
Potent topical steroids Steroid injections into bald patches Systemic corticosteroids Wigs/hair pieces/false lashes and brows Counselling
Which conditions are most associated with erythema nodosum?
Streptococcal throat infections Sarcoid TB IBD Pregnancy Behçet;s
What are the clinical features of lichen planus?
Oral lesions: white lace-like lesions on the sides of cheeks and tongue
Skin lesions: Shiny, flat-topped plaques with fine white lines over them
Vaginal: Painless white streaks in a lacy or fern-like pattern
Painful and persistent erosions and ulcers (erosive lichen planus )
Scarring, resulting in adhesions, resorption of labia minora and introital stenosis
What are the clinical features of lichen sclerosus?
Lichen sclerosus presents as white crinkled or thickened patches of skin that tend to scar.
Affects the non-hair bearing areas of the vagina, penis and anus
Extremely itchy and sore lesions
Very painful sex
Complications: infection, squamous cell carcinoma
Steroid management
