What is cellulitis?
Cellulitis is an acute suppurative bacterial infection of the skin and soft tissue, often with involvement of underlying structures: fascia, muscles and tendons.
Causes of cellulitis
It is most often due to B haemolytic streptococci or Staphylococcus aureus.
Less common causes include:
- Anaerobic bacteria
- Mycobacteria
- Proteus
- Pseudomonas
- Crytococcus (rarely)
- It usually (but not always) follows some discernible wound.
- It is often a complication of immunosuppression like diabetes and HIV/AIDS.
Epidemiology
The prevalence is unclear. It is commoner in adult males above 45 years of age and young children.
Risk factors for cellulitis
Risk factors include:
- Immunosuppression,
- Malnutrition,
- Obesity,
- Elderly persons,
- Peripheral vascular disease
- Lymphoedema and recent injuries to the skin.
Symptoms of cellulitis
- Areas of oedema; rapidly spreading
- Erythema (rapidly becomes intense and spreads)
- Tenderness and warmth: Often accompanied by fever, lymphangitis, regional lymphadenitis
- Systemic signs of toxicity
- Area becomes infiltrated and pits on pressure
- Sometimes the central part becomes nodular and surrounded by a vesicle that ruptures
and discharges pus and necrotic material
Differential diagnoses
- Erysipelas
- Deep vein thrombosis
Complications of cellulitis
Complications are unusual in immunocompetent adults. Children and compromised adults are at higher risk.
The following are the complications of cellulitis:
- Septicaemia
- Gangrene
- Metastatic abscesses
- Recurrent cellulitis may predispose to chronic lymphoedema
Investigations
- Blood culture
- Full Blood Count with differentials
- Fasting blood glucose
- HIV screening
- Wound swab for microscopy, culture and sensitivity
- Urinalysis
Treatment for cellulitis
Treatment objectives
- Eradicate infection
- Treat underlying immune suppression
- Prevent complications
Drug treatment
Ampicillin/cloxacillin
Adult: 500mg-1 g orally every 6 hours for 5-7 days
Child:
- under 5 years: a quarter adult dose;
- 5 – 10 years: half adult dose
Or:
Cloxacillin
Adult: 500 mg orally every 6 hours for 5-7 days
Child
- under 5 years: a quarter adult dose;
- 5 – 10 years: half adult dose
Ciprofloxacin
Adult: 250-750 mg orally every 12 hours for 5 – 7days
Child: Ciprofloxacin is contraindicated in children.
Ceftriaxone
Adult: 1 g intravenously or intramuscularly daily for 3 days
Child:
- Neonate, 20-50 mg/kg by intravenous infusion over 60 minutes;
- 1 month – 12 years, body weight less than 50 kg: 50 mg/kg by deep intramuscular injection or intravenous injection over 2-4 minutes, or by intravenous infusion
- Intramuscular injections over 1 g should be divided over more than 1 site.
- Doses of 50 mg/kg and more should be given by intravenous infusion only.
- Use only when there is significant resistance to other drugs
Tetanus Prophylaxis
Surgical treatment
- May need incision and drainage or debridement
Caution, contraindications
- Ciprofloxacin is contraindicated in growing adolescents and children below 12 years; also contraindicated in pregnancy
How to prevent cellulitis
Treat any wound promptly.