ICD-10 Code A50.31 – Late congenital syphilitic interstitial keratitis (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code A50.31 – Late congenital syphilitic interstitial keratitis
What it is
This code identifies interstitial keratitis occurring as a late manifestation of congenital syphilis. It refers to corneal inflammation from prior Treponema pallidum infection acquired before birth.
Clinical signs
Typical findings include corneal inflammation with haze, pain, photophobia, tearing, and reduced vision. Clinical features vary; refer to documentation, especially if the record links the eye disease to congenital syphilis.
When to use this code
Use A50.31 when the provider documents late congenital syphilitic interstitial keratitis or clearly states that interstitial keratitis is due to congenital syphilis. It is appropriate for ophthalmology, infectious disease, or pediatric records describing a late sequela of congenital infection. Check documentation if the causal link is not explicit.
Do not use for
Do not use this code for nonsyphilitic keratitis, acquired syphilis, or other congenital syphilis manifestations without corneal involvement. Check documentation when the eye condition is described only as keratitis.
Coding tip
Confirm that the record supports both congenital syphilis and interstitial keratitis before assigning A50.31.