Cellulitis & Erysipelas

Question 1

Definition

Answer 1

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

Question 2

Aetiology

Answer 2

· Often results from:

o Penetrating injury
o Local lesions (e.g. insect bits)
o Fissuring (e.g. anal fissures)

· These allow pathogenic bacteria to enter the skin

· Most common organisms
o Streptococcus pyogenes
o Staphylococcus aureus
o NOTE: beware of MRSA

· Cellulitis of the orbit (orbital cellulitis) is usually caused by Haemophilus influenzae

Question 3

Risk factors

Answer 3

o Skin break

o Poor hygiene

o Poor vascularisation of tissue (e.g. due to diabetes mellitus)

Question 4

Epidemiology

Answer 4

VERY COMMON

Question 5

Presenting symptoms

Answer 5

· History of cut, scratch or injury

· Periorbital Cellulitis - painful swollen red skin around the eye

· Orbital Cellulitis - painful or limited eye movements, visual impairment

Question 6

Signs on physical examination

Answer 6

· Lesion
o Erythema
o Oedema
o Warm tender indistinct margins
o Pyrexia - may suggest systemic spread
· NOTE: exclude the presence of an abscess (aspirate if pus suspected)

· Periorbital
o Swollen eye lids
o Conjunctival infection

· Orbital Cellulitis
o Proptosis
o Impaired visual acuity and eye movements
o Test for RAPD , visual acuity and colour vision

Question 7

Investigations

Answer 7

· Bloods - WCC, blood culture

· Discharge - sample and send for MC&S

· Aspiration (if pus is suspected)

· CT/MRI - if orbital cellulitis is suspected (helps assess posterior spread of infection)

Question 8

Management plan

Answer 8

· Medical
o Oral penicillins (e.g. flucloxacillin) or tetracyclines are effective
o If hospital-acquired - treat empirically based on local guidelines and change depending on the sensitivity of cultured organisms

· Surgical
o Orbital decompression may be needed in orbital cellulitis (EMERGENCY)

· Abscess
o Aspirate
o Incision and drainage
o Excised completely

Question 9

Possible complications

Answer 9

· Sloughing of overlying skin

· Orbital cellulitis - may cause permanent loss of vision, spread to the brain, abscess formation, meningitis, cavernous sinus thrombosis

Question 10

Prognosis

Answer 10

Good prognosis