Cellulitis + Erisipelas

Question 1

What is cellulitis?

Answer 1

acute non-purulent spreading infection of the subcutaneous tissue, causing overlying skin inflammation

Question 2

List 3 broad causes of cellulitis and examples of each

Answer 2

Penetrating injury (IV cannulation)
Local lesions (e.g. insect bits)
Fissuring (e.g. anal fissures)
These allow pathogenic bacteria to enter the skin

Question 3

What are the most common causative organisms of cellulitis?

Answer 3

Streptococcus pyogenes
Staphylococcus aureus
(+MRSA)

Question 4

What is the most common causative organism of cellulitis involving the orbit

Answer 4

Haemophilus influenzae

often arises from adjacent sinuses

Question 5

Describe the epidemiology of cellulitis

Answer 5

VERY COMMON

Question 6

Describe the presentation of a patient with cellulitis

Answer 6

Hx of cut, scratch or injury
Periorbital: painful swollen red skin around eye
Orbital: painful or limited eye movements, visual impairment

Question 7

List 4 signs of cellulitis

Answer 7

Erythema
Oedema
Warm tender indistinct margins
Pyrexia (suggests systemic spread)

Question 8

How do you exclude abscess when suspecting cellulitis?

Answer 8

Test for fluid thril or fluctuation

Aspirate if pus suspected

Question 9

Give 2 periorbital signs of cellulitis

Answer 9

Swollen eye lids

Conjunctival injection

Question 10

Give 2 signs of orbital cellulitis

Answer 10

Proptosis

Impaired visual acuity + eye movements

Question 11

What should you test for if suspecting orbital cellulitis?

Answer 11

Eye movements
RAPD
Visual acuity
Colour vision

Question 12

What investigations should be performed in suspected cellulitis?

Answer 12

Bloods: WCC, high CRP, blood culture
Discharge: sample + send for MC+S
Aspiration (if pus in abscess)
CT/MRI: if orbital cellulitis (to assess posterior spread of infection)

Question 13

What is the medical management of cellulitis?

Answer 13

Oral penicillins (e.g. flucloxacillin, co-amoxiclav) or tetracyclines
If hospital-acquired: treat empirically based on local guidelines + change depending on sensitivity of cultured organisms

Question 14

When is surgical management of cellulitis necessary?

Answer 14

In orbital cellulitis may need
Orbital decompression (EMERGENCY)

Question 15

How are abscesses managed in cellulitis?

Answer 15

Aspirate
Incise + drain
Excise completely

Question 16

List 4 complications of cellulitis

Answer 16

Sloughing of overlying skin
Abscess formation
Sepsis
Necrotising fasciitis

Question 17

What is the prognosis of cellulitis?

Answer 17

Good with tx

Question 18

List 3 risk factors for cellulitis

Answer 18

Skin break
Poor hygiene
Poor vascularisation of tissue (e.g. in diabetes mellitus)

Question 19

Describe the site, borders, systemic involvement and likelihood of sepsis in cellulitis

Answer 19

Dermis + subcutaneous tissue (deep)
Patchy borders
Systemic spread is less common
Sepsis is more common

Question 20

Describe the site, borders, systemic involvement and likelihood of sepsis in erysipelas

Answer 20

Epidermis (superficial)
Well demarcated borders
Systemic involvement: Fevers + riggers
Sepsis is uncommon

Question 21

List 4 complications of orbital cellulitis

Answer 21

Permanent loss of vision
Spread to the brain
Meningitis
Cavernous sinus thrombosis

Question 22

When should a patient with cellulitis be admitted?

Answer 22

If septic (high HR, high RR + low BP)
If confused (low GCS)