What is the diagnosis for a patient with peri-incisional pain, tenderness, localized swelling, and erythema to the mid-abdomen 10 days after a Cesarean section (C-section)?

Diagnosis: Superficial Incisional Surgical Site Infection (Answer A)

This patient meets the diagnostic criteria for a superficial incisional surgical site infection (SSI), not cellulitis or deeper infection, based on the classic presentation of peri-incisional pain, tenderness, localized swelling, and erythema occurring 10 days post-cesarean section. 1

Diagnostic Criteria Supporting This Classification

The Infectious Diseases Society of America defines superficial incisional SSI as involving only the subcutaneous space between skin and underlying muscular fascia, occurring within 30 days of surgery, with at least one of the following findings: 1

• Local signs and symptoms of pain or tenderness, swelling, and erythema (all present in this patient) 1
• Purulent incisional drainage 1
• Positive culture of aseptically obtained fluid or tissue 1
• Diagnosis by the attending surgeon or physician based on clinical judgment 1

The timing at 10 days post-cesarean section is typical for SSI development, as these infections rarely occur in the first 48 hours and most commonly appear between days 4-6 postpartum. 1, 2

Why Not Deep Incisional SSI (Answer B)

Deep incisional SSI involves the deep layers of soft tissue (fascia and muscle) beneath the subcutaneous space. 1 The presentation described—localized to the mid-abdomen with peri-incisional findings—suggests superficial involvement only, without evidence of fascial or muscular layer involvement. 1

Why Not Organ/Space SSI (Answer C)

Organ/space SSI involves any part of the anatomy (organs or spaces) other than the incision itself that was opened or manipulated during the operation. 1 This patient's symptoms are clearly localized to the incision site itself, not to deeper pelvic organs or spaces. 1

Why Not Cellulitis (Answer D)

Cellulitis is not the appropriate diagnosis for a post-surgical wound infection occurring at the incision site within 30 days of surgery. 3 The correct classification is surgical site infection (specifically superficial incisional SSI), as this is a direct complication of the surgical procedure. 1 While cellulitis codes might be considered if erythema extends >5 cm from the wound edge, the primary diagnosis remains SSI. 3, 4

Critical Clinical Pearls

Assess for systemic signs that would indicate more serious infection requiring antibiotics: 1, 4

• Temperature >38.5°C 1, 4
• Heart rate >100-110 beats/minute 1, 4
• WBC count >12,000 cells/µL 1
• Erythema extending >5 cm from incision edge 1, 4

If systemic signs are absent and erythema is <5 cm, antibiotics are unnecessary—the primary treatment is opening the incision and drainage. 1

Red Flags Requiring Immediate Escalation

Any infection developing within 48 hours post-cesarean section suggests highly virulent organisms (Group A Streptococcus or Clostridium species) and requires immediate surgical exploration. 1, 2 However, this patient presents at day 10, making this less likely. 1, 2

Watch for signs of necrotizing infection: 2

• Rapidly spreading necrosis 2
• Crepitus (gas in tissues) 2
• Severe pain out of proportion to findings 2
• Skin color changes from pale to bronze to purplish-red 2