ICD-10 Code H16.259 – Phlyctenular keratoconjunctivitis, unspecified eye (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code H16.259 – Phlyctenular keratoconjunctivitis, unspecified eye
What it is
This code identifies phlyctenular keratoconjunctivitis affecting an unspecified eye. It refers to an inflammatory eye condition involving the conjunctiva or cornea when laterality is not documented.
Clinical signs
Clinical features vary; refer to documentation. Typical findings may include localized redness, irritation, tearing, photophobia, and a small elevated inflammatory lesion on the conjunctiva or cornea.
When to use this code
Use H16.259 when the clinician documents phlyctenular keratoconjunctivitis but does not specify right or left eye. It also fits when the record confirms the diagnosis and laterality is unavailable or unclear.
Choose this code for encounters focused on evaluation, monitoring, or follow-up of the condition. If the note identifies a specific eye, use the laterality-specific code instead.
Do not use for
Do not use this code for nonspecific conjunctivitis, keratitis, or other eye inflammation without documentation of phlyctenular keratoconjunctivitis. Check documentation if the eye involved is specified.
Coding tip
Verify laterality in the ophthalmology note before assigning the unspecified-eye code.