ICD-10 Code A51.2 – Primary syphilis of other sites (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code A51.2 – Primary syphilis of other sites
What it is
A51.2 identifies primary syphilis when the initial lesion is found outside the usual genital, anal, or oral sites. Use it for a first-stage Treponema pallidum infection documented in another location.
Clinical signs
Typical findings include a painless chancre or ulcer at the affected site, sometimes with local lymph node enlargement. Clinical features vary; refer to documentation.
When to use this code
Use A51.2 when the clinician documents primary syphilis and specifies an atypical site, such as skin or another nonstandard location. It applies only to the initial stage of infection, not later manifestations or congenital disease.
Do not use for
Do not use this code for secondary, latent, or tertiary syphilis, or when the lesion site is not documented. Check documentation if the record only says “syphilis” without stage or location.
Coding tip
Confirm both the primary stage and the exact site in the note before assigning A51.2.