25. Dermatology Flashcards
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What is a squamous cell carcinoma?
A locally invading cancer of keratinocytes of the epidermis. Second most common skin cancer.
RF - UV light, FHx, light skin, actinic keratosis
What is a basal cell carcinoma?
Cancer of keratinocytes in the epidermis of stratum basal. This doesn’t often metastasise and is most common skin cancer
RF - UV light, FHx, light skin
What are the four subtypes of a BCC?
- Nodular - most common, rolled edges and central ulcer
- Superficial - flat
- Morpheic - yellow, waxy, scar-like
- Pigmented - dense colour, appears like melanoma
What’s the ABCDE of lesions?
Asymmetry
Border
Colour
Diameter
Evolution
What is a malignant melanoma?
Cancer of melanocytes in epidermis. Most deadly skin cancer. It’s irregular, pigmented, may bleed, itch, ulcerate or crust.
How might we investigate a skin cancer?
Bedside - dermatoscope
Bloods - calcium, ALP, LFTs for mets
Imaging - CT/MRI/PET
Skin biopsy - breslow thickness
How would we manage SCC, BCC and melanomas?
SCC - cryotherapy, surgery, radiotherapy
BCC - surgery
Melanoma - surgery with lymph node biopsy, systemic therapy (nivolumab) and met treatment
What is eczema?
Inflammatory skin condition. Often associated with atopy and the filaggrin gene mutation.
Skin is dry, itchy, erythematous. Can have lichenification and distributed around flexure.
What are the six main types of eczema?
Atopic
Contact dermatitis
Discoid dermatitis - older people, coin-shaped
Seborrhoeic dermatitis - yellow, greasy, scaly rash
Dyshidrotic - itchy/painful blisters over hands and feet
Eczema herpeticum - medical emergency from HSV-1
What is psoriasis?
Auto-immune condition caused by hyperproliferation of keratinocytes.
Purple, silvery plaques that are dry and flakey, itchy or painful.
Signs of psoriasis not on skin?
Nail - onchyolysis, pitting, subungual hyperkeratosis
Psoriatic arthritis
Five subtypes of psoriasis?
Plaque psoriasis (most common)
Pustular
Guttate - raindrop plaques often post-strep
Flexural psoriasis
Erythrodermic - systemic body redness and inflammation
How would we investigate inflammatory skin conditions? (eczema and psoriasis)
Usually clinical diagnosis
Can do -
Skin patching for contact dermatitis
IgE for atopy
Skin biopsy
How would we manage psoriasis?
Plaque - topic hydrocortisone
Pustular - acitretin and then ciclosporin
Gutate - Phototherapy, then ciclosporin, then methotrexate
How would we manage eczema?
Acute - emollients with topical corticosteroids
Chronic/relapsing - emollients with low potency corticosteroids
What is urticaria?
Skin lesions developing rapidly from hypersensitivity reactions to a specific trigger.
Lesion is blanching, non-painful and erythematous
How would we investigate and manage urticaria?
FBC, ESR, CRP
Identify trigger
Treat trigger
Antihistamines
Oral corticosteroids if severe
What are cellulitis and erysipelas?
Bacterial infections of skin, often strep pyogenes or staph aureus.
Acute onset inflammation.
How does cellulitis present?
On dermis and subcut tissue, is patchy. Sepsis is common, rarely systemic symptoms.
How does erysipelas present?
Epidermal, well-demarcated. Systemic symptoms of fevers and rigors. Rarely septic.
Investigations for a skin infection? (e.g. cellulitis)
Usually a clinical diagnosis
Skin swab
FBC, CRP, blood cultures
CT/MRI (if orbital cellulitis)
How would we manage a skin infection? (cellulitis or erysipelas)
Ensure it isn’t growing
Oral fluids and pain relief
Oral ABx
IV ABx if severe or near eyes
Admit if septic (high HR, RR or low BP) or if confused (GCS)
What is necrotising fasciitis?
Life-threatening subcutaneous soft tissue infection. (can start out as cellulitis)
