Cellulitis

Question 1

Define cellulitis

Answer 1

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

Question 2

Aetiology of cellulitis

4

Answer 2

Often resulting from:
Penetrating injury
Local lesions (e.g. insect bites)
Fissuring (e.g. anal fissures)

—> these allow pathogenic bacteria to enter skin

Question 3

Most common organisms causing cellulitis

3

Answer 3

Streptococcus pyogenes
Staphylococcus aureus
Orbital cellulitis usually caused by Haemophilus influenzae

Question 4

Risk factors for cellulitis

3

Answer 4

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

Question 5

Epidemiology of cellulitis

prevalence

Answer 5

VERY COMMON

Question 6

Presenting symptoms of cellulitis

3

Answer 6

History of cut, scratch or injury
Periorbital cellulitis - painful swollen red skin around eye
Orbital cellulitis - painful or limited eye movements, visual impairment

Question 7

Signs of cellulitis on physical examination

3 groups

Answer 7

Lesion
Periorbital
Orbital

Question 8

Signs of cellulitis on physical examination - lesion

4

Answer 8

Erythema
Oedema
Warm tender indistinct margins
Pyrexia - may suggest systemic spread

Question 9

Signs of cellulitis on physical examination - periorbital

2

Answer 9

Swollen eyelids

Conjunctival infection

Question 10

Signs of cellulitis on physical examination - orbital

3

Answer 10

Proptosis
Impaired visual acuity & eye movements
Test for RAPD, visual acuity & colour vision

Question 11

Investigations for cellulitis

4

Answer 11

Bloods - WCC, blood culture
Discharge - sample & send for MC&S
Aspiration (if pus suspected)
CT/MRI - if orbital cellulitis suspected (helps assess posterior spread of infection)

Question 12

Management of cellulitis - medical

2

Answer 12

Oral penicillins (e.g. flucloxacillin) or tetracycline are effective 
If hospital acquired, treat empirically based on local guidelines & change depending on sensitivity of cultured organisms

Question 13

Management of cellulitis - surgical

Answer 13

Orbital decompression may be needed in orbital cellulitis (EMERGENCY)

Question 14

Management of cellulitis - abscess

3

Answer 14

Aspirate
Incision & drainage
Excised completely

Question 15

Complications of cellulitis

2

Answer 15

Sloughing of overlying skin
Orbital cellulitis - may cause permanent loss of vision, spread to brain, abscess formation, meningitis, cavernous sinus thrombosis

Question 16

Prognosis of cellulitis

Answer 16

Good prognosis