Cellulitis & Erysipelas

Question 1

What is cellulitis?

Answer 1

• acute spreading infection of the skin with
• visually indistinct borders that
• principally involves the dermis & subcutaneous tissue

Question 2

What is erysipelas?

Answer 2

• distinct form of superficial cellulitis with
• notable lymphatic involvement
• raised, sharply demarcating it from uninvolved skin

Question 3

Describe the epidemiology of cellulitis.

Answer 3

• men > women
• lower limbs > elsewhere
  *

Question 4

What are the causes of cellulitis?

Answer 4

• disruptions in the cutaneous barrier –> entry of microorganisms to dermal + subcutaneous tissues
• common microorganisms :
  
  • Beta-haemolytic streptococci (non-purulent cellulitis)
  • Staphylococcus aureus
• but in hosts w altered immunity : other microbes can also cause cellulitis:
  
  • Pseudomonas aeruginosa
  • Pasteurella multocida
  • Capnocytophaga canimorsus
  • Vibrio vulnificus,
  • Cryptococcus neoformans

Question 5

What are the risk factors of Cellulitis / Erysipelas?

Answer 5

• immunocompromised
  
  • more susceptible to –> aerobic gram-negative bacteria (e.g., Pseudomonas aeruginosa, Helicobacter cinaedi)
• diabetes mellitus
  
  • –> diabetic foot ulcers can be complicated by cellulitis
• recent hospital admission –> ?MRSA

Question 6

Which organisms are the main causes of erysipelas?

Answer 6

almost always caused by group A streptococcus

Question 7

What are the presenting symptoms of cellulitis?

Answer 7

• painful
• redness
• warmth
• swelling
• Macular erythema with indistinct borders
• oedema

Question 8

What are the physical signs of cellulitis on examination?

Answer 8

same as presenting symptoms

Question 9

What are the primary investigations for suspected cellulitis?

Answer 9

• FBC
  
  • –> raised WBC
• pustular focus culture
  
  • –> aids antimicrobial selection + identifies resistant pathogens

Question 10

What findings on examination lead to ?abcess?

Answer 10

• tender fluctuance
• incomplete response to antimicrobial therapy

Question 11

What investigation is indicated for cellulitis associated with ?abscess?

Answer 11

• US

Question 12

What is the primary management for cellulitis & what factors does this depend on?

Answer 12

• semi-synthetic penicillinase-resistant penicillin OR
• first-generation cephalosporin

I.V. or oral - depending on

• systemic signs or symptoms
• comorbid medical conditions
• ability to tolerate oral medications

Question 13

What type of antibiotic is indicated in those with a severe type I hypersensitivity reaction to beta lactams?

Answer 13

• non-beta-lactam antibiotic

Question 14

Why are fluoroquinolones prescribed with care?

Answer 14

have been associated with

• disabling and potentially irreversible musculoskeletal / nervous system adverse events

hence reserved as 2nd line options in skin and soft-tissue infections when primary

Question 15

What is the management plan for erysipelas?

Answer 15

Follows cellulitis’

Question 16

Which organism is increasingly being found as a cause of Cellulitis & Erysipelas?

How is this treated?

Answer 16

• MSRA
• non-beta lactam / ceftaroline

Question 17

What are the possible complications of Cellulitis & Erysipelas?

Answer 17

• cellulitis –> sepsis
  
  • if caused by vibrio vulnificus after salt water exposure
  • risk factor = pre-existing liver disease
• chronic oedema + reoccurance of cellulitis
  
  • caused by damage to local vasculature & lymphatics

Question 18

What is the prognosis of Cellulitis / Erysipelas?

Answer 18

• Most episodes of cellulitis resolve with therapy
• major sequelae are absent
• ~ increased chance of reoccurance (due to damage to lymphatics)