Signs of Wound Infection — When to Seek Medical Help

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June 08, 2026

Signs of Wound Infection — When to Seek Medical Help

Wound infection is one of the most common complications in wound care, with surgical site infections alone affecting 2-5% of operated patients in the US (CDC, 2020). Early recognition and treatment prevent progression from local to systemic infection.

Early Signs of Wound Infection

Sign	What to Look For	Action
Increased Pain	Worsening pain at wound site, especially after previously improving	Assess for other signs; this is often the FIRST indicator
Erythema (Redness)	Redness extending >2cm from wound edge, or expanding over time	Mark the border with a pen and check for expansion in 4-6 hours
Local Heat	Wound area feels warmer than surrounding skin or contralateral site	Inflammatory response marker — with other signs, suspect infection
Edema (Swelling)	New or increasing swelling around wound	Localized vs spreading — spreading edema is concerning
Increased Exudate	Sudden increase in drainage volume, or change to purulent (cloudy, yellow/green)	Purulent drainage = definitive infection sign until proven otherwise
Odor	New foul or unusual smell from wound	May indicate anaerobic bacteria — requires culture
Delayed Healing	Wound not progressing or deteriorating after 2 weeks of appropriate care	Consider occult infection or biofilm

NERDS and STONEES — Biofilm Detection

The NERDS/STONEES mnemonic (Sibbald et al., 2011) helps differentiate superficial critical colonization (NERDS) from deep infection (STONEES):

NERDS (Superficial): Non-healing, Exudate increase, Red friable tissue, Debris/slough, Smell
STONEES (Deep): Size increasing, Temperature elevated, Os (probes to bone), New breakdown areas, Erythema/Edema, Exudate, Smell

Systemic Signs — When Infection Has Spread

Seek emergency medical care if the patient has:

Fever (>38degC / 100.4degF) or chills
Red streaks (lymphangitis) extending from the wound toward the heart — this is a medical emergency
Rapidly expanding redness or swelling
Malaise, fatigue, confusion (especially in elderly)
Nausea, vomiting, or loss of appetite
Tachycardia (rapid heart rate) and/or hypotension

These may indicate sepsis, a life-threatening systemic response to infection requiring immediate hospital treatment.

High-Risk Wounds for Infection

Bite wounds (animal or human) — 10-20% infection rate; prophylactic antibiotics recommended
Puncture wounds — especially through shoes (Pseudomonas risk)
Contaminated traumatic wounds — dirt, debris, foreign bodies
Surgical wounds in contaminated fields (bowel surgery, abscess drainage)
Diabetic foot wounds — neuropathy masks pain, vascular disease impairs healing
Immunocompromised patients — chemotherapy, steroids, HIV, transplant
Wounds >6-8 hours old before treatment — bacterial colonization threshold exceeded

Management

For suspected local wound infection:

Obtain wound swab for culture and sensitivity (Levine technique: rotate swab over 1cm2 of clean wound bed for 5 seconds)
Increase dressing change frequency to daily
Consider topical antimicrobial dressing (silver, iodine, PHMB, medical-grade honey)
Debride non-viable tissue if present
Monitor for 48-72 hours — if no improvement, escalate to systemic antibiotics

Do NOT: Use topical antiseptics (hydrogen peroxide, povidone-iodine solution) on healing granulation tissue — these are cytotoxic to fibroblasts and delay healing (Thomas et al., Journal of Wound Care, 2009). Use only sustained-release antimicrobial dressings.

References: Sibbald RG, et al. "NERDS and STONEES." Advances in Skin and Wound Care, 2011. IWII Wound Infection in Clinical Practice, 2016. CDC SSI Prevention Guidelines, 2017.