A51.4 – Other secondary syphilis

ICD-10-CM 2027 diagnosis code · Infections with a predominantly sexual mode of transmission

Non-billable header

ICD-10-CM code A51.4

Code: A51.4 (claims format: A514)
Description: Other secondary syphilis
Billable: No – use a more specific code below
Valid for: Dates of service October 1, 2026 – September 30, 2027 (FY2027)
Chapter: 1. Certain infectious and parasitic diseases (A00-B99)
Block: A50-A64 Infections with a predominantly sexual mode of transmission
Parent codes: A51

Billable codes under A51.4

A51.4 is a header code and cannot be used on claims. Choose the most specific code:

A51.41 – Secondary syphilitic meningitisBillable
A51.42 – Secondary syphilitic female pelvic diseaseBillable
A51.43 – Secondary syphilitic oculopathyBillable
A51.44 – Secondary syphilitic nephritisBillable
A51.45 – Secondary syphilitic hepatitisBillable
A51.46 – Secondary syphilitic osteopathyBillable
A51.49 – Other secondary syphilitic conditionsBillable

Notes inherited from parent codes

Instructional notes at a category or block level apply to every code below it.

Block A50-A64

Excludes1 (not coded here):

nonspecific and nongonococcal urethritis (N34.1)
Reiter's disease (M02.3-)

Excludes2 (not included here):

human immunodeficiency virus [HIV] disease (B20)

Related codes in A51

A51.0 – Primary genital syphilisBillable
A51.1 – Primary anal syphilisBillable
A51.2 – Primary syphilis of other sitesBillable
A51.3 – Secondary syphilis of skin and mucous membranesHeader
A51.5 – Early syphilis, latentBillable
A51.9 – Early syphilis, unspecifiedBillable

Frequently asked questions

What is ICD-10 code A51.4?

A51.4 is the ICD-10-CM code for other secondary syphilis, in the block A50-A64 (Infections with a predominantly sexual mode of transmission).

Is A51.4 a billable code?

No. A51.4 is a header code with more specific child codes; report one of the billable codes listed above.

What category does A51.4 belong to?

It belongs to category A51 – Early syphilis.

Source: CDC/NCHS ICD-10-CM FY2027 code files, tabular list and index. Reference only – code assignment must follow the official ICD-10-CM guidelines and documentation in the medical record.