Dermatology Flashcards
Describe the pathological processes which result in acne
- Increased sebum production by sebaceous glands
- Blockage of pilosebaceous units
- Follicular epidermal hyperproliferation
- Infection with Propionibacterium acnes
How does acne vulgaris present?
Features of acne vulgaris:
- Open comedones (blackheads)
- Closed comedones (white heads)
- Inflammatory papules and pustules
- Hypertrophic/keloid scarring
- Hyperpigmentation
Conservative management of acne vulgaris
- Avoid overwashing
- Avoid picking
Pharmacological management of acne vulgaris
1st line
- Topical benzoyl peroxide
- Topical clindamycin/erythromycin
- Topical retinoids
2nd line:
- Low dose oral antibiotics, e.g. erythromycin, tetracycline
- Hormonal therapy in women (OCP)
3rd line:
- Oral retinoids (TERATOGENIC!!)
What is the other name given to ‘eczema’?
Dermatitis
What are the types of eczema?
Atopic eczema and contact dermatitis
What causes atopic eczema?
Atopy - hereditary predisposition to developing an allergic reaction (eczema, allergic rhinitis, asthma)
Describe the pathological processes which result in eczema
- Abnormal epithelial barrier function - allows irritant agents to penetrate and reach immune cells
What are the clinical features of atopic eczema?
- Itchy, red, scaly patches
- Commonly presents in flexures (in infants, often presents on the face)
Conservative management of atopic eczema
- Avoid irritants/exacerbating factors, e.g. strong chemicals, dog/cat fur
- Avoid scratching
Pharmacological management of atopic eczema
- Regular use of emollients
- Antihistamines and topical corticosteroids in attacks: mild steroids (e.g. hydrocortisone) used on face and more potent steroids (e.g. betamethasone) used on rest of body
- Immunosuppressants, e.g. ciclosporin, and phototherapy if severe
Complications of eczema
Secondary Staph. aureus infection due to broken skin - treat with antibiotics
Distinguishing contact dermatitis from atopic eczema from clinical features…
- Itchy, red, scaly rash (same as atopic eczema)
BUT
- Unusual pattern of rash (i.e. not in flexures) and clear cut demarcation/odd-shaped rash
Investigations for contact dermatitis
Patch testing may be necessary to identify particular allergen
Conservative management of contact dermatitis
Avoid allergen
Pharmacological management of contact dermatitis
- Antihistamines and topical corticosteroids used in attacks - mild steroids (e.g. hydrocortisone) used on face and more potent steroids (e.g. betamethasone) used on rest of body
When does psoriasis most commonly present?
Late teens/early twenties and 50s/60s
What causes psoriasis?
Combination of genes and environmental triggers: e.g. group A strep infection, high alcohol consumption, stress
Types of psoriasis…
- Chronic plaque psoriasis (MOST COMMON)
- Flexural/inverse psoriasis
- Guttate (‘raindrop’-like pattern)
- Erythrodermic and pustular psoriasis
How does chronic plaque psoriasis present?
- Well-demarcated, red plaques covered with silvery scales
- Commonly affects extensor surfaces and scalp
- May affect sites of sites of skin trauma (Koebner phenomenon)
Other associated clinical features:
- Nail changes: pitting/onycholysis/discoloration
- Psoriatic arthritis
Describe the pathological processes which cause psoriasis
- Keratinocyte hyperproliferation
- Infiltration of inflammatory cells
Pharmacological management of psoriasis
1st line:
- Topical vitamin D analogues, e.g. calcipotriol
- Topical corticosteroids
- Coal tar preparations
- Topical retinoids
2nd line:
- Phototherapy
3rd line:
- Immunosuppressants, e.g. ciclosporin, methotrexate
- Oral retinoids
What are the three types of skin cancer we need to know?
- Basal cell carcinoma
- Squamous cell carcinoma
- Malignant melanoma
What is the main cause of skin cancer?
Sun exposure
How does basal cell carcinoma present?
- ‘Shiny, pearly nodule’
- Rarely ulcerates/metastasises
How does squamous cell carcinoma present?
- Ill-defined nodule that ulcerates and grows rapidly
- More aggressive than BCC - can metastasise
- Premalignant features: solar keratoses and Bowen’s disease
How does malignant melanoma present?
- Most common sign is appearance of a new mole or a change in an existing mole
- Most serious from of skin cancer - metastasises early
Describe the management of basal cell carcinoma
Surgical excision
Describe the management of squamous cell carcinoma
Surgical excision
Describe the investigation of malignant melanoma
ABCDE criteria to distinguish benign from malignant moles:
Asymmetry of mole Border irregularity Colour variation Diameter Elevation
Then the Glasgow 7 point checklist is used for guidance on referral:
- Change in size (2 points)
- Change in shape (2 points)
- Change in colour (2 points)
- Diameter >6mm (1 point)
- Inflammation (1 point)
- Oozing or bleeding (1 point)
- Mild itch/altered sensation ( 1 point)
If points add up to 3 or more, urgent suspected cancer pathway referral (2 week wait)
Investigation involves CT scan to check for metastases
Describe the management of malignant melanoma
- If local disease: surgical excision
- If metastatic: radiotherapy, immunotherapy
Where are the most common site for venous/arterial/neuropathic ulcers?
Venous:
- Medial gaiter region (above medial malleolus)
Arterial:
- Anterior shin
- Foot and ankle
Neuropathic:
- Foot (especially big toe) and ankle
What are the risk factors for an arterial ulcer?
- Arterial disease (atherosclerosis) and its associated risk factors
How does an arterial ulcer present?
- Small, punched-out appearance, well defined edges
- Necrotic base
- Painful
- Reduced peripheral pulses
- ABPI (ankle brachial pressure index) <0.8
How is an arterial ulcer investigated?
- Doppler studies
How is an arterial ulcer managed?
- Vascular reconstruction
- Amputation if necessary
What are the risk factors for a venous ulcer?
- Varicose veins
- DVT
How does a venous ulcer present?
- Large, shallow, irregular edges, exudative
- Normal peripheral pulses
- ABPI >0.8
How is a venous ulcer managed?
Compression bandaging
What are the risk factors for a neuropathic ulcer?
- Diabetes mellitus
- Neurological disease
How does a neuropathic ulcer present?
- Variable size
- May be surrounded by a callus (found at pressure sites)
How is a neuropathic ulcer managed?
- Surgical debridement
- Control DM
- Advise appropriate footwear
- Podiatry
What is cellulitis?
Bacterial infection of the deep subcutaneous tissue
Which types of bacteria most commonly cause cellulitis?
- Streptococcus pyogenes
- Staphylococcus aureus
List some risk factors which may lead to cellulitis
- Immunosuppression
- Trauma
- Ulcers
How does cellulitis present?
5 cardinal signs of inflammation:
- Rubor (redness)
- Calor (warm)
- Tumor (swelling)
- Dolor (pain)
- Loss of function
May be systemically unwell
How is cellulitis managed?
Abx: either Flucloxacillin or Benzylpenicillin
What is necrotising fasciitis?
Bacterial infection of the deep fascia and tissue necrosis
Which types of bacteria most commonly cause necrotising fasciitis?
Group A haemolytic strep
List some risk factors which may lead to necrotising fasciitis
- Immunosuppression
- Abdominal surgery
How does necrotising fasciitis present?
- Severe pain
- Tissue necrosis
- Systemically unwell
How is necrotising fasciitis managed?
- Surgical debridement
- IV Abx
