Cellulitis Flashcards
What is cellulitis?
- Infection of the deep dermis and subcutaneous tissue
- Develops when micro-organisms gain entry to the dermal and subcutaneous tissues via disruptions in the cutaneous barrier (eg. minor skin injury)
What causes cellulitis?
Most common causative bacteria are Streptococcus pyogenes (catalase -ve) and Staphylococcus aureus (catalse +ve)
What are the risk factors for cellulitis?
- Venous insufficiency
- Eczema
- Oedema
- Breaks in the skin, such as cuts, abrasions, insect bites, or surgical wounds
- Chronic conditions that compromise skin integrity - venous insufficiency or lymphedema, pressure sores, ulcers, recent trauma
- Obesity
- Diabetes
- Immunosuppression
- Intravenous drug use
- Recent history of cellulitis
Summarise the epidemiology of cellulitis
- VERY COMMON
What are the presenting symptoms of cellulitis?
- Erysipelas: painful, shiny light-red swelling of clearly defined area of skin. May also cause blisters and swelling of nearby lymph nodes. Fever and malaise.
- Cellulitis: reddened skin is less clearly defined, often it is dark-red/purple. Can produce pus.
- History of cut, scratch or injury
- Periorbital Cellulitis - painful swollen red skin around the eye
- Orbital Cellulitis - painful or limited eye movements, visual impairment
What signs of cellulitis can be found on physical examination?
- Lesion
o Erythema
o Oedema
o Pyrexia - may suggest systemic spread
o Calor (heat)
o Swelling
o Pain
o Poorly demarcated margins
- Systemic upset: fever, malaise
- Lymphadenopathy
- Rarely blisters and pustules (severe disease)
- Often evidence of breach of skin barrier e.g. trauma, ulcer etc. - 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
What investigations are used to diagnose/ monitor cellulitis?
- Clinical Diagnosis → only request further tests if signs of systemic illness or septicaemia
- High WCC and CRP
- Skin Swab MCS → can identify pathogen and antibiotics susceptibility
- If patient admitted and septicaemia suspected → blood cultures and sensitivities
- Hospital admission if there is significant systemic upset and/or co-morbidities.
How is cellulitis managed?
- Mark the area of erythema to aid in detection of rapidly spreading cellulitis, and to monitor treatment response
- Elevate if possible
- Review if wound debridement is required
- Flucloxacillin → 1st line treatment for mild/moderate cellulitis
- If severe systemic symptoms (eg. septic signs, tachycardic + hypotensive) or significant comorbidites → hospital admission + IV co-amoxiclav, cefuroxime, clindamycin or ceftriaxone
- If Penicillin Allergic → clarithromycin first, erythromycin (in pregnancy), or doxycycline
- Abx if:
- Has Eron Class III or Class IV cellulitis.
- Has severe or rapidly deteriorating cellulitis (for example extensive areas of skin).
- Is very young (under 1 year of age) or frail.
- Is immunocompromized.
- Has significant lymphoedema.
- Has facial cellulitis (unless very mild) or periorbital cellulitis.
What classification is used to guide the management of cellulitis?
ERON Classification:
- Class I (no systemic systems or co-morbidities) → managed in primary care with oral antibiotics
- Class II (systemically unwell or systemically well with co-morbidity) → short term hospitalization
- Class III (significant systemic upset) or IV (sepsis or nec fasc) → urgent hospital admission.
What complications may arise following cellulitis?
- Abscess formation
- Lymphangitis (infection of lymphatic vessels)
- Systemic spread of infection (sepsis)
- Recurrence of cellulitis
- Chronic or recurrent lymphedema
- Scarring and changes in skin texture
