Cellulitis

Question 1

What is the pathophysiology of cellulitis?

Answer 1

Entry of bacteria through a break in the skins barrier leading to infection in the subcutaneous and dermis.
Most commonly caused by streptococcus pyogens, less commonly s.aureus

Question 2

What are the risk factors for cellulitis?

Answer 2

• Breaks in the skin,
• Chronic conditions which compromise skin integrity eg, venous insufficiency, ulcers.
• Obesity,
• Diabetes,
• Immunosupression,
• IVDU,
• History of cellulitis

Question 3

What are the signs and symptoms of cellulitis?

Answer 3

• Commonly found on the shins and is unilateral. Bilateral cellulitis is rare.
• Erythema and heat,
• Swelling and pain,
• Blistering and bleeding (only in severe disease)
• Systemic upset
• Lymphadenopathy

Question 4

What are the differential diagnosis for cellulitis?

Answer 4

• DVT,
• Erysipelas (superficial cellulitis which has well-demarcated margins)
• Superficial thrombophlebitis
• Necrotizing fasciitis

Question 5

Explain the Eron classification of Cellulitis

Answer 5

Class I - No signs of systemic toxicity and person has no uncontrolled co-morbidities.
Class II - Systemically unwell or has a comorbidities which may delay resolution (PAD, venous insufficency)
Class III - Significant systemic upset (tachycardia, confusion, hypotension) or unstable co-morbidities or limb-threatening infection.
Class IV - Sepsis of life threatening infection eg, Necrotizing fasciitis

Question 6

What are the investigations for cellulitis?

Answer 6

Normally a clinical diagnosis but can do following investigations:
- Bloods (FBC, CRP, U&Es) and blood cultures
- Wound swab if open wound
- USS to look for fluid collections

Question 7

Which patient’s should be admitted for IV antibiotics?

Answer 7

• Eron class III or IV
• Severe or rapidly deteriorating cellulitis (extensive area of skin)
• Very young (<1y) or frail
• Immunocompromised
• Significant lymphoedema
• Facial cellulitis or periorbital cellulitis

Question 8

What is the management of cellulitis?

Answer 8

Eron class I - High dose flucloxacillin is first line. Clarithromycin/doxy if pen allergic, erythromycin in pregnancy.
Eron class II - Admit for 48hours of hospital IV abx then OPAT.
Eron class III-IV - Admit for IV antibiotics such as IV co-amoxiclav and potential surgery

Question 9

What are the surgical indications for cellulitis?

Answer 9

• Necrotising infection
• Abscess

Question 10

What are the complications of an cellulitis

Answer 10

• Abscess formation,
• Lymphangitis (infection of lymphatic vessels)
• Sepsis,
• Persistant leg ulcers
• Recurrence of cellulitis
• Chronic lymphoedema
• Scarring or changes in skin texture

Question 11

What are the complications of periorbital cellulitis

Answer 11

Optic nerve damage, cavernous sinus thrombosis, intracranial infection