Dermatology Flashcards
Give the subcategories for the following types of lesion:
- Flat (2)
- Fluid- filled (3)
- Raised (2)
- Flat: macule (small), patch (large)
- Fluid-filled: Vesicle (<0.5cm), pustule (pus filled vesicle), bulla (>0.5 cm)
- Raised: papule (<0.5cm), nodule (>0.5cm)
Give the arrangement of basal cells, squamous cells and melanocytes in normal epidermis.
Which is the most common and second most common type of skin cancer?
- Squamous above basal in layers.
- Basal cells in a line, interrupted by occasional melanocyte
Basal cell carcinoma most common. Squamous cell carcinoma second most common
Define squamous cell carcinoma.
Give 4 risk factors for squamous cell carcinoma
- Cancer of keratinocytes in epidermis. 2nd most common skin cancer
Risk fx: - UV light
- Actinic keratosis (pre-cancerous condition)
- FHx
- Lighter skin
Give 5 features of squamous cell carcinoma lesion.
Describe 2 features of its invasion.
- Hyperkeratotic
- Scaly/ crusty
- Ulcerated
- Non-healing
- Rolled edges
- Local invasion into dermis, can metastasise
Give definition of basal cell carcinoma
- Give 3 risk factors for basal cell carcinoma.
Cancer of keratinocytes in epidermis in stratum basale Risk fx: - UV light - FHx - Lighter skin
Give 5 features of basal cell carcinoma lesion
- Describe 3 features of its invasion.
- Nodule
- Pearly edges
- Rolled edges
- Central ulcer (rodent ulcer)
- Central fine telangiectasia
- Slow growing, local invasion into dermis, doesn’t metastasise
Give the 4 subtypes of basal cell carcinoma
- Nodular: most common
- Morpheic: yellow waxy plaque, scar-like
- Superficial: flat shape
- Pigmented: dense colour/ specks of colour.
Give 3 risk factors for malignant melanoma
- UV light
- FHx
- Lighter skin
Give 5 features of a malignant melanoma lesion
Describe the invasion of malignant melanoma (2)
ABCDE
- Asymmetrical
- Irregular border
- Pigmented colour
- Diameter >6mm
- Evolution: may bleed, itch, ulcerate, crust over
- Local invasion- into dermis
- Can metastasise
Give 4 subtypes of malignant melanoma
- Superficial spreading- most common
- Lentigo maligna: flat lesions on face, elderly
- Nodular: domed shape, rapid growth
- Acral lentiginous: palms, soles, nail beds- non-caucasians
How should the 3 types of skin cancer be referred?
What investigation is used to measure melanoma invasion?
Which investigations can be used for staging skin cancer?
- Melanoma and SqCC urgent referral
- BCC: routine referral
- Clark level/ Breslow thickness- obtained by skin biopsy.
- CT/ MRI/ PET
What are melanocytic lesions?
Give 3 features of their morphology.
- Benign neoplasms of melanocytes in epidermis
- Often congenital, arise during childhood.
- Symmetrical, flat, regular borders (not ABCDE)
Give 2 risk factors for eczema aka dermatitis
Give 5 features of eczema lesions
- PMHx/ FHx of atopy- food allergies, hay fever, asthma
- Immunocompromised
- Dry
- Itchy
- erythematous
- Flexure distribution
- Lichenification if chronic
Describe the 6 types of eczema:
- Atopic dermatitis
- Contact dermatitis
- Discoid dermatitis
- Seborrhoeic dermatitis
- Dyshidrotic aka pompholyx
- Eczema herpeticum
- Atopic dermatitis: type 1 hypersensitivity- IgE mediated, flexures.
- Contact dermatitis: Type 4 hypersensitivity (delayed). Often nickel/ latex. Irritant or allergic
- Discoid dermatitis: middle aged/ elderly, coin shaped plaques
- Seborrhoeic: yellow, greasy scaly rash. Eyebrows, nasolabial, scalp distribution (cradle cap)
- Dishydrotic: itchy/ painful blisters- palms and plantars.
- Herpeticum: Medical emergency, can disseminate, superimposed HSV-1
Give 3 triggers of psoriasis
Give 4 features of psoriatic lesions.
- Stress, smoking, alcohol.
- Purple, silvery plaques
- Dry flaky skin
- Itchy painful
- Extensors and scalp.
Give 3 nail signs of psoriasis
- Onycholysis
- Pitting
- Subungual hyperkeratosis
Give 1 sign of psoriatic arthritis
Give 4 causes of onycholysis
- Symmetrical polyarthritis
- Psoriasis
- Fungal infection
- Trauma
- Thyrotoxicosis
Describe the following subtypes of psoriasis
- Plaque psoriasis
- Pustular aka palmo-plantar
- Guttate
- Flexural
- Erythrodermic
- Plaque-most common
- Pustular: plaques/ pustules on palms and plantars
- Guttate: raindrop plaques- 2 weeks post-strep
- Flexural: body folds: axilla, groin, peri-anal area
- Erythrodermic: systemic body redness and inflammation. Often temperature dysregulation, electrolyte imbalances. Requires hospitalisation
Give 3 risk factors for cellulitis and erysipelas.
Both lesions have acute onset and inflammation.
Give two causative organisms of cellulitis and erysipelas.
- Wound, ulcer, bites
- IV cannula
- Immunosuppression.
- Strep. pyogenes or staph aureus
Differentiate cellulitis and erysipelas by the following:
- Site
- Borders
- Systemic
- Sepsis
Cellulitis:
- Dermis, subcutaneous tissue
- Patchy borders
- Less common systemic
- Sepsis more common
Erysipelas
- Epidermis
- Well demarcated borders
- Systemic fevers and rigors
- Sepsis less common
Give 5 complications of cellulitis
- Abscess
- Sepsis: medical emergency
- Necrotising fasciitis: surgical emergency
- Periorbital cellulitis: medical emergency: IV Abx
- Orbital cellulitis: medical emergency: IV Abx, surgery
When would you CT/MRI for cellulitis?
- Orbital cellulitis- need to identify posterior spread of infection
Give 3 conservative management steps for cellulitis.
Give 2 reasons to admit to hospital with cellulitis
- Draw around lesion
- Monitor observations
- Oral fluids
Admit if
Sepsis: High HR/ RR, low BP
Confusion: AVPU, GCS
Give examples of the following causes of erythema nodosum:
- Infection (3)
- Systemic disease (3)
- Drugs (1)
- Other (1)
- Infection: strep pyogenes, TB, HIV
- Systemic disease: IBD, sarcoidosis, Behcet’s disease
- Drugs: sulphonamides
- other: pregnancy
