Cellulitis is a common bacterial infection of the skin and subcutaneous tissue that spreads along tissue planes, usually caused by streptococci or Staphylococcus aureus.
Definition:
Acute, spreading, suppurative inflammation of the skin and subcutaneous tissue.
Etiology:
Most common: Group A β-hemolytic Streptococcus, Staphylococcus aureus.
Less common: Gram-negative bacilli, anaerobes (esp. in diabetics, immunocompromised).
Risk Factors:
- Diabetes mellitus
- Immunosuppression
- Chronic edema/lymphedema
- Trauma, insect bites, surgical wounds
- Peripheral vascular disease
🔎 Clinical Features
Local signs:
- Redness, swelling, warmth, pain, tenderness.
- Diffuse margins (ill-defined, unlike abscess).
- Skin may appear “peau d’orange” (orange peel-like).
Systemic signs:
- Fever, chills, malaise, tachycardia.
- Lymphangitis and regional lymphadenitis may be present.
⚕️ Diagnosis
Clinical diagnosis →
diffuse erythema, tenderness, warmth without localized pus collection.
Investigations:
CBC: leukocytosis.
CRP, ESR: raised.
Blood cultures: if systemic signs.
Ultrasound: to rule out abscess (fluctuation not always clear).
💊 Management
1. General:
Rest, limb elevation.
Analgesics, antipyretics.
2. Antibiotics (systemic, not just topical):
3. Local care:
Warm compresses.
Treat entry point (e.g., fissure, wound, tinea pedis).
4. Surgical intervention:
Only if abscess develops → incision & drainage.
⚠️ Complications
- Abscess formation.
- Necrotizing fasciitis (if rapid progression, severe pain, crepitus).
- Septicemia.
- Chronic lymphedema.
- Recurrent cellulitis.
