ICD-10 Code A36.3 – Cutaneous diphtheria (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code A36.3 – Cutaneous diphtheria
What it is
A36.3 identifies cutaneous diphtheria, a diphtheria infection involving the skin rather than the throat. Use it when documentation specifies skin infection caused by Corynebacterium diphtheriae.
Clinical signs
Typical findings include a chronic, nonhealing skin lesion or ulcer, sometimes with a gray membrane or dirty-looking base. Clinical features vary; refer to documentation.
When to use this code
Use this code when the provider clearly documents cutaneous diphtheria or diphtheritic skin infection. It may also apply when the note links a skin lesion to C. diphtheriae and no other site is the focus. Check documentation if the record only says “diphtheria” without a skin site.
Do not use for
Do not use A36.3 for respiratory diphtheria, carrier status, or a skin infection with no diphtheria organism documented. If the diagnosis is uncertain, check documentation.
Coding tip
Code the documented site first; if the record does not clearly identify cutaneous involvement, verify the diagnosis before assigning A36.3.