Dermatology Flashcards
Which skin cancers can metastasise?
Melanoma and squamous cell carcinoma
First-line medication for non-bullous impetigo?
Hydrogen peroxide cream.
Describe the typical features of impetigo
‘Golden’, crusted skin lesions typically found around the mouth.
Alternative treatment for impetigo than hydrogen peroxide cream?
Topical fusidic acid.
How long should children with impetigo be excluded from school?
Until the lesions are crusted and healed or 48 hours after commencing antibiotic treatment.
Which conditions are seborrhoeic dermatitis associated with?
HIV and Parkinson’s disease
Describe the aetiology of seborrhoeic dermatitis
Caused by an inflammatory reaction related to a proliferation of a normal skin inhabitant, a fungus called Malassezia furfur.
Describe the typical features of seborrhoeic dermatitis
- Eczematous lesions on sebum-rich areas, such as scalp (dandruff), periorbital, auricular and nasolabial folds.
- Otitis externa and blepharitis may develop.
First-line treatment for scalp seborrhoeic dermatitis?
Ketoconazole 2% shampoo.
What is the most common skin cancer in renal transplant patients?
Squamous cell carcinoma.
Describe the appearance of squamous cell carcinoma
Indurated (firm), nodular/plaque-like, frequently ulcerate and surrounding tissue often inflamed.
Describe the appearance of actinic keratosis
- Found on sun-exposed sites and have a scaly surface without induration.
- They tend to be soft.
- Small, crusty or scaly lesions that may be pink, red, brown or same colour as skin.
Describe the appearance of basal cell carcinomas
Initially translucent or shiny nodules with pearly rolled edges and peripheral telangiectasia on sun-exposed sites e.g. head and neck. Later may ulcerate leaving a central ‘crater’.
Describe appearance of seborrhoeic keratosis
Benign pigmented lesions which have a warty ‘stuck-on’ appearance.
Describe the step-wise approach to chronic plaque psoriasis
- First-line: potent corticosteroid applied once daily plus vitamin D analogue applied once daily.
- 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 twice daily for up to 4 weeks OR a coal tar preparation applied once/twice daily.
Describe the secondary care management of chronic plaque psoriasis
- Phototherapy - narrowband UVB light.
- First-line: oral methotrexate.
- Ciclosporin.
- Systemic retinoids.
- Biological agents e.g. infliximab.
Management of actinic keratosis?
Fluorouracil cream
Which drug is most suitable for long-term use in psoriasis?
Calcipotriol (vitamin D analogue)
An area of rapidly worsening painful eczema is an early sign of what?
Eczema herpeticum
What causes eczema herpeticum?
HSV
Treatment of eczema herpeticum?
IV aciclovir (hospital admission)
Describe Stevens-Johnson syndrome
A severe systemic reaction affecting the skin and mucosa that is almost always caused by a drug reaction e.g. sulphonamides.
Describe the rash seen in Stevens-Johnson syndrome
- Maculopapular rash with target lesions.
- In erythematous areas blisters and erosions appear when the skin is rubbed gently.
Treatment first line for dermatophyte nail infections
Oral terbinafine
What is onychomycosis?
Fungal nail infection
Risk factors for onychomycosis
- Increasing age
- Diabetes mellitus
- Psoriasis
- Repeated nail trauma
Autoimmune blistering skin disorder associated with coeliac disease?
Dermatitis herpetiformis
What is pyoderma gangrenosum?
It’s a rare, non-infectious, inflammatory disorder that causes painful ulcers. 50% idiopathic, 10-15% association with IBD. Treatment involves steroids.
Name the type of squamous cell carcinoma in-situ affecting the epidermis, that usually presents as a red, scaly, crusted patch on sun-exposed areas of the body
Bowen’s disease
What is the first line treatment for Bowen’s disease?
Topical 5-fluorouracil
Which oral antibiotic can be used in pregnancy for acne?
Erythromycin
Are topical retinoids contraindicated in pregnancy?
Yes
Widespread pruritus, particularly at night, and linear erythematous lesions are classic features of what?
Scabies
What is the first line management of scabies?
Permethrin 5%
Describe the appearance of different types of burns
- Superficial epidermal (first degree): red and painful, dry, no blisters.
- Partial thickness superficial dermal (second degree): pale pink, painful, blistered.
- 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.
Deficiency in which substance causes hypogonadotropic hypogonadism and peri-anal dermatitis?
Zinc deficiency
Niacin deficiency causes a triad of which symptoms?
Diarrhoea, dermatitis, and dementia.
Describe the features of vitamin C deficiency
Ecchymoses, perifollicular haemorrhages, and corkscrew hairs and purpura.
Guttate psoriasis is associated with which infection?
Streptococcal.
Describe the features of guttate psoriasis
Acute onset of tear-drop scaly papules on trunk and limbs. More common in children and adolescents.
Management for guttate psoriasis?
- Most cases resolve spontaneously within 2-3 months.
- Topical treatments if symptomatic.
What is the most common form of melanoma?
Superficial spreading melanoma.
Describe the ABCDE approach to melanoma
- Asymmetry.
- Border irregularity.
- Colour variation.
- Diameter >6mm.
- Evolving.
Describe the features of lentigo maligna melanoma
Slow growing mole on chronically sun-exposed areas of skin.
Name some drugs which can exacerbate psoriasis
BLANQ:
- Beta blockers
- Lithium
- Alcohol, ACEi
- NSAIDs
- Quines (Antimalarials)
Describe the features of rosacea
- Flushing often first symptom.
- Telangiectasia.
- Later develops into persistent erythema with papules and pustules.
- Affects nose, cheeks and forehead.
- Untreated can lead to rhinophyma.
Describe the step wise approach to the management of rosacea
- Predominantly flushing/erythema but limited to telangiectasia: topical brimonidine gel (alpha-adrenergic agonist to temporarily reduce redness).
- Mild-to-moderate papules &/or pustules: topical ivermectin.
- Moderate-to-severe papules &/or pustules: topical ivermectin + oral doxycycline.
- Referral if symptoms haven’t improved with optimal management in primary care or patients with rhinophyma.
What is the most common type of skin cancer in western world?
BCC
Molluscum contagiosum is caused by which virus?
Pox virus
Describe the characteristic features of molluscum contagiosum
Pinkish or pearly white papules with a central umbilication appearing as clusters on trunk and flexures in preschool aged children.
Describe the treatment for molluscum contagiosum
- Self-limiting condition, treatment not recommended.
- Avoid sharing towels, clothing and baths.
- Exclusion from school, gym or swimming not necessary.
What is the most common malignancy of the lower lip?
SCC
Which surgery for SCC is preferred for cosmetically important sites?
Mohs micrographic surgey
BCC vs SCC
- BCC: most common type of skin cancer, ‘pearly’ rolled edges, umbilicated centre, telangiectasia, slow growing.
- SCC: more common in immunosuppressed, hyperkeratotic lesion, crusting and ulceration.
A 22-year-old male comes to see you the GP. He explains that there are strange spots on his body that he first noticed over 2 months ago. The spots are slightly itchy and he assumed they would go away without treatment. He has no past medical history and states he leads an active life with regular exercise. On examination, there are 6 hypopigmented spots on the left posterior aspect of his neck.
Pityriasis versicolor
How can pityriasis rosea initially present?
Herald patch
Cause of erythema multiforme (‘target lesions’)
- Hypersensitivity reaction that is most commonly triggered by infections.
Melanoma that can arise in areas not associated with sun exposure e.g. soles of feet and palms
Acral lentiginous melanoma
Describe features of lichen planus
- 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.
Management of lichen planus
Potent topical steroid
Precancerous dermatosis that is a precursor to squamous cell carcinoma
Bowen’s disease
What is the most common cause of erythema multiforme
HSV
Management of pityriasis versicolor
Topical antifungal. NICE advises ketoconazole shampoo as this is more cost effective for large areas.
What is the most common malignancy associated with acanthosis nigricans?
Gastrointestinal adenocarcinoma
