A51.1

What This Code Means

This is a sexually transmitted infection caused by bacteria that affects the anal area during the earliest stage of syphilis. It typically presents as a painless sore or ulcer at the site of infection.

Coding Tips

• •Ensure documentation clearly indicates primary syphilis (first stage) with anal location to distinguish from secondary or latent syphilis
• •Verify that the patient has been tested and confirmed positive for syphilis, and document any sexual contact history or partner notification attempts as this is a reportable disease