Nonpurulent mastitis associated with lactation

This code signifies inflammation of the breast tissue that is not characterized by pus formation and is directly related to the period of breastfeeding or lactation. It typically presents with localized pain, redness, swelling, and warmth in the breast, often accompanied by systemic symptoms like fever and malaise.

Apply this code when documentation clearly indicates mastitis occurring during lactation, and the physician explicitly states or implies the absence of purulent discharge or abscess formation. This diagnosis is supported by clinical findings of inflammation without signs of infection requiring incision and drainage.

• Differentiate from purulent mastitis (O91.1-) which involves abscess formation or pus.
• Ensure documentation specifies the association with lactation; otherwise, consider non-puerperal mastitis codes (N61.0, N61.1).
• Always sequence this code as a primary diagnosis when it is the reason for the encounter.