Clinical manifestation of infection

PEDIS grade

IDSA infection severity

No symptoms or signs of infectiona

1

Uninfected

Local infection involving only skin and subcutaneous tissue (no involvement of deeper tissues or systemic signs described below); if erythema is present, it must be >0.5 cm to ≤2 cm around the ulcer

Exclude other causes of an inflammatory skin response (eg, trauma, gout, acute Charcot arthropathy, fracture, thrombosis, venous stasis)

2

Mild

Local infection (as above) with erythema >2 cm or involving structures deeper than skin and subcutaneous tissues (eg, abscess, osteomyelitis, septic arthritis, fasciitis) and no systemic inflammatory response signs (see below)

3

Moderate

Local infection (as above) with signs of SIRSb

4

Severec

a Infection defined as the presence of ≥2 of the following: local swelling or induration; erythema; local tenderness or pain; local warmth; purulent discharge (thick, opaque to white or sanguineous secretion).

b At least 2 of the following: temperature >38°C or <36°C; heart rate >90 bpm; respiratory rate >20 breaths/min or PaCO2 <32 mm Hg; white blood cell count >12×109/L or <4×109/L or ≥10% immature (band) forms.

c Ischemia may increase the severity of any infection, and the presence of critical ischemia often makes the infection severe. Systemic infection may sometimes manifest with other clinical findings, such as hypotension, confusion, vomiting, or evidence of metabolic disturbances, such as acidosis, severe hyperglycemia, and new-onset azotemia.