K04.4 Acute apical periodontitis of pulpal origin

Billable ICD-10-CM code, FY2026. Acts as a Complication or Comorbidity (CC) as a secondary diagnosis.

Applicable to

• Acute apical periodontitis NOS

Excludes1 (never code together)

• acute periodontitis (K05.2-)

MS-DRG index

Defines the logic of DRG(s) 011-013 in MDC PRE.

Approximate ICD-9-CM (GEMs)

• 522.4 Acute apical periodontitis of pulpal origin

Code annotations containing back-references to K04.4

Back-references to K04.4

• Type 1 Excludes: K05.2 Aggressive periodontitis ("acute apical periodontitis (K04.4)")

Diagnosis Index entries for K04.4

• Periodontitis (chronic) (complex) (compound) (local) (simplex) › apical › acute (pulpal origin)
• Septic › teeth, tooth (pulpal origin)

Nearby codes

• K04.01 Reversible pulpitis
• K04.02 Irreversible pulpitis
• K04.1 Necrosis of pulp
• K04.2 Pulp degeneration
• K04.3 Abnormal hard tissue formation in pulp
• K04.4 Acute apical periodontitis of pulpal origin (this code)
• K04.5 Chronic apical periodontitis
• K04.6 Periapical abscess with sinus
• K04.7 Periapical abscess without sinus
• K04.8 Radicular cyst
• K04.9 Other and unspecified diseases of pulp and periapical tissues