Hordeolum internum left eye, unspecified eyelid

This code signifies an internal hordeolum, commonly known as a stye, affecting the left eye. An internal hordeolum is an acute bacterial infection of a meibomian gland within the tarsal plate, presenting as a painful, red, and swollen lump on the inner surface of the eyelid.

Apply this code when documentation specifies an internal hordeolum located in the left eye, without further detail regarding the specific eyelid (upper or lower). This is appropriate when the physician's notes confirm the diagnosis and laterality but do not differentiate between upper or lower lid involvement.

• Ensure documentation clearly specifies "internal" hordeolum and "left eye."
• If the specific eyelid (upper or lower) is documented, use a more precise code (e.g., H00.021 for upper, H00.024 for lower).
• Do not confuse with external hordeolum (stye of Zeis or Moll gland) or chalazion, which have different code assignments.