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Cellulitis is a spreading bacterial infection of the dermis and subcutaneous tissues ( CREST 2005 )

It is a bacterial skin and soft tissue infection Generally affects the lower limbs Erysipelas – Greek erythros (red) + pella (skin ) is considered a subtype
Evidence suggests a large overlap between the two conditions Seen and managed frequently by different specialists as GPs, surgeons , general medics , and dermatologists Seen frequently in adults and a very common cause for admission
In 2008-9 – 82 113 admissions in England and Wales mean length of stay of 7.2 days 
This is rising ( data from Australia and USA ) Approximately 7 % of all patients with cellulitis are hospitalised Significant resource and financial burden on healthcare systems- – common global burden

Streptococcus species – usually groups A ( S. pyogens for most cases ) Staphylococcus aureus Dog/ cat bite Pasteurella multocida , Capnocytophaga canimorus Less common Streptococcus pneuomoniae, Haeophilus influenzae, Gram negative bacillin , Anaerobes

Skin integrity Immunity Vasculature -Risk factor for development of cellulitis

Risk factors- Pregnant White race Venous / lymph insufficiency Lymphoedema Diabetes Old age Peripheral arterial disease. Previous h/o cellulitis Athletes foot Psoriasis Insect / animal bite Injection drug use Immunosuppression , neutropenia , chemotherapy , immersion injury Ulcers , eczema , wound

Following an episode of cellulitis 
○ about 7 % develop chronic leg oedema
○ persistent leg ulceration
○ 29 % suffer another episode within 3 yrs Skin changes eg discoloration may persist

Lymphoedema is the
 most important risk factor for recurring cellulitis . 25-60 % of patients with recurring
 episodes suffer with 

Check- Previous episodes Duration Symptoms as
Fever /Malaise
Tenderness Identify any precipitating causes eg
○ local lesions
○ insect /human bites
○ break in skin due to injury or trauma
○ athletes foot
○ chronic oedema and lymphoedema
○ leg ulceration
○ IV cannulation Comorbidities

Presents as red , painful , hot , swollen and tender area of skin Check vitals to r/o systemic involvement Look for -
Skin break
Fungal skin infection 
Bullae and blisters Outline visible margins with indelible marker Unilateral or bilateral ( cellulitis almost always unilateral ) Eczematous or cellulitic or both Lymphangitis –> red lines streaking away from the area of infection
or lymphadenopathy Any evidence suggestive of DVT
Consider leg measurement BJGP recommends a leg raise test to 45° for 1-2 mins- cellulitis erythema will persist

Leukocytosis and elevated CRP are present in 34-50 % and 77-97 % of patients
U&E and LFT as indicated Swab of exudate Blood culture ( rarely positive ) Imaging – usually not needed
Consider if
○ diagnosis is in doubt
○ underlying abscess suspected or
 necrotizing fascitis ( MRI )
 No effective diagnostic modality for cellulitis and many clinical conditions appear similar

Differential -Stasis dermatitis Stasis ulcers Septic arthritis Gout Congestive heart failure Ruptured Bakers cyst Non-specific oedema DVT Thrombophlebitis Erysipelas Lipodermatosclerosis Pyoderma gangrenosum Impetigo Lyme disease Vasculitis Contact dermatitis

Complications -Necrotizing fasciitis-extensive and progressive necrosis of the s/c tissue and fascia ( search images on google) Myositis Subcutaneous abscesses Sepsis Post-streptococcal nephritis Death

Erons class of cellulitis

Class 1-Patient has no sign of systemic toxicity no controlled co-morbidities Class 2- Patients are
 systemically unwell or systemically well with a co-morbidity such which may complicate or delay resolutions as

○ peripheral vascular disease
○ chronic venous insufficiency
○ morbid obesity
○ diabetes
○ chronic liver disease , CKD Class 3 Patients may significant systemic upset as
○ acute confusion
○ high pulse rate and resp rate
○ hypotension or
 Suffer with unstable co-morbidities that may
○ interfere with a response to therapy
○ have a limb threatening infection due to a vascular compromise Class 4- Sepsis syndrome life threatening infections such as necrotizing fascitis

No role of topical antibiotics Usually treated with high dose of 
Flucloxacillin x 7 days ( before or long after meals – traditionally 1st line )
Clarithromycin ( if allergic ) Cellulitis with known lymphoedema- Amoxicillin or Clarithromycin Facial cellulitis – Augmentin x 7 days
Clarithromycin if allergic to penicillin Doxycyline or Minocycline ,Cephalexin , Dicloxacillin are options Clindamycin is an option ( used in necrotizing fascitis )
better tissue penetration than beta lactams
Resistance and C Diff diarrhoea can be problematic- adv to stop if diarrhoea develops Cellulitis from a wound contaminated by fresh/ sea water – contact microbiologist Continue antibiotics for another 7 days if no improvement after initial course and the person remains systemically well ( CKS ) Vancomycin- 1st choice for MRSA , linezolid is an alternative

No consensus on optimum duration/ route or choice of antibiotics -
 refer to local guidance as well-Young children ( eg < 1 year ) or old and frail Progressive infection despite antibiotic treatment eg spreading margins or lymphangitis
CKS advice- consider admission/ advice if no improvement after 2 weeks Pain unbearable or rapid and dramatic worsening 
( r/o necrotising fascitis ) Immunocompromized Significant lymphoedema Facial or peri-orbital cellulitis

Blistering , ulceration – refer D/N or TV Nurse Wet cellulitis can be treated with potassium permanganate solution Issue a non-adherent dressing but if the exudate is copient more absorbent dressing may be helpful

Offer analgesia ( evidence for use of NSAIDs ) Ensure hydration Arrange F/U ( CKS advice within 48 hrs )-tel/F2F Leg elevation where applicable Dorsiflexion exercise to relieve oedema Advice to observe for
skin blistering , broken skin , exudate or venous ulceration ( seek D/N input ) Seek help if
○ antibiotics not tolerated
○ cellulitis becomes worse
○ signs of systemic upset Warn about risk of recurrence and preventative measures ( Eg NHS , Patient UK or BAD PIL )



City Hospitals Sunderland on cellulitis,%20June%202012).pdf

British Association of Dermatology on cellulitis

NHS on cellulitis

Health Navigator New Zealand


Antbiotic prescribing from HSE IE

NICE- cellulitis and erysiplelas antibiotic prescribing

Dermnet NZ on cellulitis




  1. CREST guidelines on the management of cellulitis in adults June 2005,%202005.pdf
  2. Cellulitis : current insights into pathophysiology and clinical management D.R Cranedonk et al The Netherlands Journal of Medicine November 2017 , Vol 77 , No 9, Pages 366-378
  3. Cellulitis- acute CKS NHS December 2016
  4. Diagnosis and management of cellulitis Gokulan Phoenix et al BMJ 2012 ; 345 : e4955
  5. The assessment , diagnosis and treatment of cellulitis by Pauline Beldon Tissue viability nurse consultant , Epsom and St Helier University Hospitals NHS Trust
  6. Management of cellulitis : current practice and research questions Br J Gen Pract 2018 ; 68 (677 ) : 595-596
  7. John Hopkins ABX guide Cellulitis
    Valeria Fabre, M.D.John G. Bartlett, M.D.
  8. Providing evidence-based care for patients with lower-extremity cellulitis by Darlene Hanson PhD et al Wound Care Advisor
  9. Raff AB, Kroshinsky D. Cellulitis: A Review. JAMA. 2016 Jul;316(3):325-337. DOI: 10.1001/jama.2016.8825.
  10. Cannon J, Dyer J, Carapetis J, Manning L. Epidemiology and risk factors for recurrent severe lower limb cellulitis: a longitudinal cohort study. Clin Microbiol Infect. 2018;24(10):1084‐1088. doi:10.1016/j.cmi.2018.01.023 ( Abstract )
  11. Cannon J, Rajakaruna G, Dyer J, Carapetis J, Manning L. Severe lower limb cellulitis: defining the epidemiology and risk factors for primary episodes in a population-based case-control study. Clin Microbiol Infect. 2018;24(10):1089‐1094. doi:10.1016/j.cmi.2018.01.024 ( Abstract )
  12. Epidemiology and risk factors for recurrent severe lower limb cellulitis: a longitudinal cohort study J. Cannon J. Dyer J. Carapetis L. Manning Clinical Microbiology and Infection Volume 24, ISSUE 10, P1084-1088, October 01, 2018

  13. NICE Cellulitis and erysipelas : antimicrobial prescribing via


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