ICD-10 Code A36.86 – Diphtheritic conjunctivitis (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code A36.86 – Diphtheritic conjunctivitis
What it is
Diphtheritic conjunctivitis is a conjunctival infection caused by diphtheria bacteria. It is a rare manifestation of diphtheria that affects the eye surface and may be associated with systemic illness.
Clinical signs
Clinical features vary; refer to documentation. Findings may include conjunctival inflammation, eyelid swelling, and a grayish membrane on the eye surface, but you should code only when diphtheritic conjunctivitis is documented.
When to use this code
Use A36.86 when the record specifically identifies conjunctivitis due to diphtheria. It may be supported by an ophthalmic note, infectious disease assessment, or discharge diagnosis naming the condition. Do not infer this code from generic red eye or conjunctivitis alone.
Do not use for
Do not use this code for routine bacterial, viral, allergic, or unspecified conjunctivitis. If the documentation does not clearly link the eye infection to diphtheria, check documentation and choose a more accurate conjunctivitis code.
Coding tip
Assign A36.86 only when diphtheria is explicit in the chart; otherwise, code the documented conjunctivitis type.