A51 - Early syphilis

Version 2023
Short Description:Early syphilis
Long Description:Early syphilis
Status: Not Valid for Submission
Version:ICD-10-CM 2023
Code Classification:
  • Certain infectious and parasitic diseases (A00–B99)
    • Infections with a predominantly sexual mode of transmission (A50-A64)
      • Early syphilis (A51)

A51 is a non-specific and non-billable ICD-10 code code, consider using a code with a higher level of specificity for a diagnosis of early syphilis. The code is not specific and is NOT valid for the year 2023 for the submission of HIPAA-covered transactions. Category or Header define the heading of a category of codes that may be further subdivided by the use of 4th, 5th, 6th or 7th characters.

Specific Coding for Early syphilis

Non-specific codes like A51 require more digits to indicate the appropriate level of specificity. Consider using any of the following ICD-10 codes with a higher level of specificity when coding for early syphilis:

  • BILLABLE CODE - Use A51.0 for Primary genital syphilis
  • BILLABLE CODE - Use A51.1 for Primary anal syphilis
  • BILLABLE CODE - Use A51.2 for Primary syphilis of other sites
  • NON-BILLABLE CODE - A51.3 for Secondary syphilis of skin and mucous membranes
  • BILLABLE CODE - Use A51.31 for Condyloma latum
  • BILLABLE CODE - Use A51.32 for Syphilitic alopecia
  • BILLABLE CODE - Use A51.39 for Other secondary syphilis of skin
  • NON-BILLABLE CODE - A51.4 for Other secondary syphilis
  • BILLABLE CODE - Use A51.41 for Secondary syphilitic meningitis
  • BILLABLE CODE - Use A51.42 for Secondary syphilitic female pelvic disease
  • BILLABLE CODE - Use A51.43 for Secondary syphilitic oculopathy
  • BILLABLE CODE - Use A51.44 for Secondary syphilitic nephritis
  • BILLABLE CODE - Use A51.45 for Secondary syphilitic hepatitis
  • BILLABLE CODE - Use A51.46 for Secondary syphilitic osteopathy
  • BILLABLE CODE - Use A51.49 for Other secondary syphilitic conditions
  • BILLABLE CODE - Use A51.5 for Early syphilis, latent
  • BILLABLE CODE - Use A51.9 for Early syphilis, unspecified

Patient Education


Syphilis is a sexually transmitted disease caused by bacteria. It infects the genital area, lips, mouth, or anus of both men and women. You usually get syphilis from sexual contact with someone who has it. It can also pass from mother to baby during pregnancy.

The early stage of syphilis usually causes a single, small, painless sore. Sometimes it causes swelling in nearby lymph nodes. If you do not treat it, syphilis usually causes a non-itchy skin rash, often on your hands and feet. Many people do not notice symptoms for years. Symptoms can go away and come back.

The sores caused by syphilis make it easier to get or give someone HIV during sex. If you are pregnant, syphilis can cause complications, or you could lose your baby. In rare cases, syphilis causes serious health problems and even death.

Syphilis is easy to cure with antibiotics if you catch it early. Correct usage of latex condoms greatly reduces, but does not completely eliminate, the risk of catching or spreading syphilis. If your or your partner is allergic to latex, you can use polyurethane condoms. The most reliable way to avoid infection is to not have anal, vaginal, or oral sex.

Centers for Disease Control and Prevention

[Learn More in MedlinePlus]

Code History