Cellulitis Flashcards
Define cellulitis
acute spreading infection of the skin with visually indistinct borders that principally involves the dermis and SC tissue
Define erysipelas
distinct form of superficial cellulitis with notable lymphatic involvement - raised and sharply demarcated from uninvolved skin
What is the aetiology of cellulitis
Disruptions in the cutaneous barrier → micro-organisms gain entry into the dermal and SC tissue
Beta-haemolytic streptotocci (pyogenes)
Staph aureus
Pseudomonas (hot tubs, sponges)
Vibrio vulnificus (salt water)
Aeromonas hydrophila (fresh water)
Streptococcus pneumoniae, Haemophilus influenzae, gram negative bacilli, and anaerobes (injury, burns, and other co‐existing diseases e.g. people who are immunocompromised, have diabetes, cancer, or malnutrition)
What are the risk factors for cellulitis
Preceding event that caused a break in the skin e.g. trauma (bite, burn, laceration)
Diabetes → ulceration
Venous insufficiency → ulceration
Eczema
Oedema and lymphoedema
Obesity
Pregnancy
Previous episodes of cellulitis
Toe-web abnormalities
What are the symptoms of cellulitis
Cellulitis: Acute, onset of red, painful, hot, swollen skin
Erysipelas: Well-demarcated, bright-red raised skin
Rash: red, painful, warm, swollen
Swelling
Blistering
Bullae
Bleeding → petechiae or ecchymosis, blisters, cutaneous haemorrhage
Fever, malaise, nausea, rigors
What are the differentials for cellulitis
Erysipelas
Chronic venous insufficiency
DVT
Septic arthritis
Acute gout
Rupture Baker’s cyst
Thrombophlebitis
Cutaneous abscess
What are the signs of cellulitis and erysipelas on examination
Obs: Fever
Skin:
- red, painful, hot, swollen skin
- Lower limbs, unilateral
- Well-demarcated border that can be marked with pen
- Rapidly spreading
± blistering
± petechiae/ecchymoses
± peau d’orange (orange-peel appearance due to oedema around hair follicles)
± lymphadenopathy, lymphangitis
Erysipelas = well-demarcated RAISED skin
What investigations should be done for cellulitis
Bedside: wound swab for culture (wounds only), nose/throat swabs
Bloods: blood cultures, FBC, ESR/CRP
Other: US ± aspiration (if abscess present), skin biopsy (if doubts), plain X-ray (?osteomyelitis, gas gangrene)
What are the classifications of cellulitis
Eron classification
Class I — no signs of systemic toxicity + no uncontrolled comorbidities.
Class II — either systemically unwell or systemically well but with a comorbidity (e.g. peripheral arterial disease, chronic venous insufficiency, or morbid obesity) which may complicate or delay resolution of infection.
Class III — significant systemic upset, e.g. acute confusion, tachycardia, tachypnoea, hypotension, or unstable comorbidities that may interfere with a response to treatment, or a limb-threatening infection due to vascular compromise.
Class IV — sepsis or a severe life-threatening infection, such as necrotizing fasciitis.
What is the management for cellulitis
?sepsis → admit
- Draw around the extend of infection
- High dose oral Abx e.g. oral flucloxacillin 4x daily (allergy → clarithromycin, near nose/eyes → co-amoxiclav)
- Advice:
- Paracetamol/ibuprofen
- Adequate fluids
- Elevate affected area
- Avoid compression - Safety net
+ follow up after 3 days
What features of cellulitis may require admission
Class III or IV eron
Severe or rapidly deteriorating
Young <1yo or frail
Immunocompromise
Facial cellulitis
Orbital or peri-orbital
What are the complications for cellulitis
Sepsis
Chronic oedema due to damage to draining lymphatics
Abscess
Necrotising fasciitis
Peri-orbital cellulitis
Myositis
Recurrence
What is the prognosis for cellulitis
Excellent
Resolves with therapy, major sequelae uncommon
May recur (8-20%) or leave residual lymphatic damage
What is necrotising fasciitis and what are the types
Infection of the fascia, necrotising
Toxin release + gas formation + thrombosis + ischaemia
Type 1: polymicrobial
Type 2: Group A Strep e.g. pyogenes
Type 3: gas gangrene (Clostridium)
What is the management for necrotising fasciitis
Broad spectrum antibiotics
Call surgeons for debridement
