Derm Flashcards
What is the aetiology of venous skin ulceration?
- Sustained venous hypertension caused by incompetent valves in deep or perforating veins, previous DVT, atherosclerosis, vasculitis e.g. RA, SLE
What is the pathophysiology of venous skin ulceration?
- Increased pressure causes extravasation of fibrinogen through the capillary walls, giving rise to perivascular fibrin deposition which leads to poor oxygenation of surrounding skin
What are the risk factors of venous skin ulceration?
- Varicose veins or DVT
What is the presentation of venous skin ulceration?
- Sloping and gradual edges
- Ulcer is large, shallow, irregular and exudative
- Usually minimal pain
- Oedema of the lower leg
- Venous eczema
- Brown pigmentation from haemosiderin
- Varicose veins
- Pulses present
- Warm skin
How is venous skin ulceration diagnosed?
- Ankle brachial pressure index (ABPI) is normal
- Doppler USS to exclude significant arterial disease
How is venous skin ulceration managed?
- High compression 4 layered bandage
- Leg elevation to reduce venous hypertension
- Antibiotics for infection
- Analgesia
- Support stockings for life
What are the risk factors of arterial skin ulceration?
- Arterial disease e.g. atherosclerosis
- Smoking
- Hypercholesterolaemia
- Diabetes mellitus
What is the presentation of arterial skin ulceration?
- Punches-out ulcers high up the leg or on the feet
- Intense pain worse when elevated
- Cold and pale leg
- Ulcer is small, sharply-defined and has a necrotic base
- Spine pale skin and loss of hair
- Absent peripheral pulses
- Arterial bruits (murmurs)
- No oedema
How is arterial skin ulceration diagnosed?
- Doppler USS to confirm arterial disease
- ABPI suggests arterial insufficiency
How is arterial skin ulceration managed?
- Keep ulcer clean and covered
- Analgesia
- Vascular reconstruction if appropriate
- Never use compression bandaging
What are the risk factors of neuropathic skin ulceration?
- Diabetes and neurological disease (peripheral neuropathy
What is the presentation of neuropathic skin ulceration?
- Often painless
- Over pressure areas of feet e.g. metatarsal heads or heels
- Variable sizes
- Surrounded by cellulitis
- Warm skin
- Normal peripheral pulses
How is neuropathic skin ulceration managed?
- Keep clean
- Remove pressure/trauma from affected area
- Correctly fitting shoes and specialist podiatrist help for diabetics
What is the presentation vasculitic skin ulceration?
- Cutaneous features which may erode and ulcerate: haemorrhagic papules, pustules, nodules, plaques
- Purpuric lesions do not blanch with pressure from a glass slide
- Pyrexia and arthralgia are common
How is vasculitic skin alteration managed?
- Analgesia
- Support stockings
- Dapsone (antibiotic) or prednisolone
What is the aetiology of cellulitis?
- Group A beta-haemolytic strep e.g. S.pyogenes
- Staph aureus
- Sometimes MRSA
What is the pathophysiology of cellulitis?
- Typically affects the lower leg or arm and spreads proximally
- Other sites include abdomen, perianal and periorbital areas
- Can also affect just one side of the face
What are the risk factors of cellulitis?
- Lymphoedema
- Leg ulcer
- Immunosuppression
- Traumatic wounds (normally an obvious point of entry of pathogen)
- Athletes foot
- Leg oedema
- Obesity
What is the presentation of cellulitis?
- Local inflammation – proximally spreading
- Hot erythema in the affected area
- Poorly demarcated margins, swelling, warmth and tenderness
- Occasionally blister especially if oedema is prominent
- Systemically unwell with pyrexia
How is cellulitis diagnosed?
- Clinical
- Skin swabs are usually negative unless taken from broken skin
- Serological testing to confirm a strep infection
How is cellulitis managed?
- Antibiotics e.g. oral phenoxymethylpenicillin or oral flucloxacillin (oral erythromycin is penicillin allergic)
- If infection is widespread then 3-5d IV antibiotic then at least 2w oral therapy
- If recurrent then give prophylaxis lose-dose antibiotics e.g. oral phenoxymethylpenicillin twice daily
What is the aetiology of necrotising fasciitis? (Type 1 and type 2)
Type 1
- Caused by a mixture of aerobic and anaerobic bacteria following abdominal surgery or in diabetics
Type 2
- Caused by group A beta-haemolytic strep, most common cause, arises in previously healthy patients
What are the risk factors of the necrotising fasciitis?
- Abdominal surgery
- Immunosuppression
What is the presentation of necrotising fasciitis?
- Fever, toxicity and pain out of proportion to skin findings
- Severe pain that is out of proportion to the skin findings at the initial site of infection, rapidly followed by tissue necrosis
- Infection track rapidly along the tissue plans, causing spreading erythema, pain and sometimes crepitus
- Multi-organ failure is common and mortality is high
