Nonpurulent mastitis associated w pregnancy, third trimester

This code signifies inflammation of the breast tissue, specifically nonpurulent (without pus formation), occurring during the third trimester of pregnancy. It indicates a localized inflammatory process, often presenting with pain, redness, and swelling, but without evidence of bacterial infection requiring drainage.

Apply this code when documentation clearly states mastitis without abscess formation or purulence, and the patient is in her third trimester of pregnancy. This diagnosis is typically made clinically based on symptoms and physical examination, distinguishing it from infectious or abscess-forming mastitis.

• Ensure documentation specifies "nonpurulent" or absence of abscess to differentiate from O91.1x codes.
• Verify the trimester of pregnancy; this code is specific to the third trimester.
• Do not use if the mastitis is postpartum; refer to codes in category O91.22 for postpartum nonpurulent mastitis.