Cellulitis is an infection of the subcutaneous tissue and skin, leading to inflammation and other systemic symptoms (Healthdirect 2020). It is caused by bacteria, with the most common causative pathogens being:
Cellulitis is common but has the potential to become life-threatening if left untreated (Mayo Clinic 2020). Prior to the invention of antibiotics, it was a fatal condition (Better Health Channel 2020).
What Causes Cellulitis?
Cellulitis occurs when bacteria enter the body and spread to the subcutaneous tissue, generally through a break in the skin caused by inflammation or damage (Better Health Channel 2020).
Skin areas that are prone to cellulitis infection include:
Despite this, it is also possible for bacteria to enter the body through undamaged skin, and in many cases, a specific cause is unable to be identified (Better Health Channel 2020).
The primary symptom of cellulitis is inflamed skin in the affected area. It may appear red, painful, swollen, sensitive and/or warm (Healthdirect 2020). The infected area may also leak pus or fluid (Better Health Channel 2020).
While any part of the body can be affected (including the face), most cellulitis infections occur in the lower leg (Healthdirect 2020).
If the infection spreads, the patient may experience systemic symptoms such as:
Fever
Chills
Sweating
Nausea and vomiting
General malaise
Pain.
(Healthdirect 2020; Better Health Channel 2020)
Complications of Cellulitis
In severe cases, cellulitis may lead to serious complications that require urgent care, such as:
Infection of other organs (e.g. pneumonia, osteomyelitis, meningitis)
Endocarditis
Bacteraemia
Thrombophlebitis.
(Stanway, Gomez & Oakley 2016; CDC 2020)
How is Cellulitis Treated?
Cellulitis is generally treated using oral antibiotics, but in cases where there are two or more symptoms of systemic infection, antibiotics are administered intravenously instead (ACSQHC 2021a).
Patients should be encouraged to elevate the affected area in order to assist with drainage, reduce swelling and alleviate pain. Analgesics such as paracetamol may also be taken to relieve symptoms (Better Health Channel 2020).
Most patients will begin to show improvement after two to three days on antibiotics and fully recover within a week (Better Health Channel 2020).
In more severe cases, surgery may be required (Better Health Channel 2020).
Cellulitis and Hospitalisation
The Fourth Australian Atlas of Healthcare Variation has identified cellulitis as the fourth most common cause of potentially preventable hospitalisation in Australia and the second most common among Aboriginal and Torres Strait Islander peoples - statistics described as ‘unacceptably high’ (ACSQHC 2021a).
Furthermore, the hospitalisation rates for cellulitis are increasing, particularly among Aboriginal and Torres Strait Islander peoples (ACSQHC 2021a).
Those who are more likely to be admitted to hospital for cellulitis are:
Older, frail people
People with certain comorbidities (e.g. diabetes, obesity, heart failure)
People living in crowded conditions
People who are experiencing socioeconomic disadvantage.
(ACSQHC 2021b)
Why Might People With Cellulitis be Hospitalised?
A high prevalence of methicillin-resistant Staphylococcus aureus in the community increases the likelihood of cellulitis hospitalisation.
One likely reason for high cellulitis hospitalisation rates is the prevalence of community-associated methicillin-resistant Staphylococcus aureus (MRSA) (strains of S. aureus that have developed antibiotic resistance) in regional and remote communities.
A high prevalence of MRSA increases the likelihood of cellulitis hospitalisation due to:
Certain antibiotics being ineffective on MRSA strains
The need for surgical drainage of MRSA infections, which typically requires hospital care
Increased rates of MRSA-associated skin abscesses, furuncles and boils that may progress to cellulitis.
(ACSQHC 2021b)
Other factors that may contribute to cellulitis hospitalisation, as well as differences between hospitalisation rates in different geographical locations, include:
Diagnostic error (under-diagnosis or over-diagnosis)
High rates of diabetes, particularly among Aboriginal and Torres Strait Islander peoples
Poorly managed diabetes
High rates of obesity, chronic venous stasis, impaired mobility and lymphoedema
High rates of streptococcal infections among Aboriginal and Torres Strait Islander peoples
Crowded housing
Use of swimming facilities
Occupational risk factors for injuring the skin
High density of people who are more prone to cellulitis (e.g. aged care facilities)
High temperatures and humidity, which are associated with open footwear and tinea
Delayed or inadequate access to healthcare
Poor health literacy
Lack of access to dermatologists
Lack of access to culturally appropriate healthcare for Aboriginal and Torres Strait Islander peoples
Lack of integrated care that refers patients to social services and programs.
(ACSQHC 2021b)
How Can We Reduce Hospitalisation for Cellulitis?
In order to reduce hospitalisation rates, earlier and more appropriate management of cellulitis is required (ACSQHC 2021c).
Strategies suggested by the Atlas include:
Addressing the social determinants of skin health (e.g. crowded living conditions)
Improving the prevention and management of chronic conditions that may lead to cellulitis
Improving access to services (e.g. podiatry, lymphoedema management)
Improving the accuracy of diagnosis
Consulting with infectious diseases specialists or dermatologists early in the course of the condition
Using community models of care instead of inpatient care in hospital
Promoting skin health among Aboriginal and Torres Strait Islander peoples.
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