2027 ICD-10-CM Diagnosis Code A51.39Other secondary syphilis of skin

ICD-10-CM Codes›A00–B99›A50-A64›A51

ICD-10-CM A51.39
CMSSource: CMS FY 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

A51.39 is a billable ICD-10-CM diagnosis code for other secondary syphilis of skin. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 606 through 607. As a secondary diagnosis, it counts as a complication or comorbidity (CC) and moves an inpatient stay to a higher severity level within its MS-DRG family. It does not count, however, when the principal diagnosis is one of 79 closely related codes. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Sexually transmitted infections (excluding HIV and hepatitis) and Skin and subcutaneous tissue infections.

Code Identity

ICD-10-CM Code
A51.39
Billable Status
Yes — Valid for Submission
Code Describes
Other secondary syphilis of skin
Short Description
Other secondary syphilis of skin
Same as the full description in the CMS dataset.
Parent Code
A51.3
Secondary syphilis of skin and mucous membranes

Code Classification

ChapterA00–B99Certain infectious and parasitic diseases
SectionA50-A64Infections with a predominantly sexual mode of transmission
CategoryA51Early syphilis
This CodeA51.39Other secondary syphilis of skin

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Acquired syphilis
  • Anal mucosa finding
  • Corona veneris
  • Lues maligna
  • Macular eruption
  • Macular syphilide
  • Oral syphilis
  • Papular syphilide
  • Pustular syphilide
  • Rash of secondary syphilis
  • Secondary syphilis of anus
  • Secondary syphilis of digestive system
  • Secondary syphilis of mouth
  • Secondary syphilis of mucous membrane
  • Secondary syphilis of pharynx
  • Secondary syphilis of skin
  • Secondary syphilis of skin and mucous membrane
  • Secondary syphilis of tonsil
  • Secondary syphilis of vulva
  • Syphilitic leukoderma
  • Syphilitic oral snail track ulcer
  • Syphilitic punched out ulcer
  • Syphilitic skin disorder
  • Ulcer of mucous membrane due to syphilis

Instructional NotesGuidance

Instructions from the official ICD-10-CM Tabular List that apply to A51.39: its own notes plus those printed at block A50-A64 and Chapter 1. A note printed at a category, block or chapter applies to every code under it.

Includes

Further defines, or gives examples of, the content of the category.

From Chapter 1 (A00-B99) Certain infectious and parasitic diseases applies to 1,068 codes
  • diseases generally recognized as communicable or transmissible

Applicable To

Conditions this code is used for: synonyms of the title or, for "other specified" codes, the conditions assigned to it. The list is not exhaustive.

  • Syphilitic leukoderma
  • Syphilitic mucous patch

Excludes1

Not coded here: the excluded code is never reported together with this one, unless the two conditions are unrelated.

On A51.39 itself
  • late syphilitic leukoderma (A52.79)
From Block A50-A64 Infections with a predominantly sexual mode of transmission applies to 142 codes
  • nonspecific and nongonococcal urethritis (N34.1)
  • Reiter's disease (M02.3-)

Excludes2

Not included here: the excluded condition is not part of this code, but a patient may have both, so both codes may be reported.

From Block A50-A64 Infections with a predominantly sexual mode of transmission applies to 142 codes
  • human immunodeficiency virus [HIV] disease (B20)
From Chapter 1 (A00-B99) Certain infectious and parasitic diseases applies to 1,068 codes
  • carrier or suspected carrier of infectious disease (Z22.-)
  • certain localized infections - see body system-related chapters
  • infectious and parasitic diseases complicating pregnancy, childbirth and the puerperium (O98.-)
  • infectious and parasitic diseases specific to the perinatal period (P35-P39)
  • influenza and other acute respiratory infections (J00-J22)

Use Additional Code

Add a second code, after this one, to fully describe the condition.

From Chapter 1 (A00-B99) Certain infectious and parasitic diseases applies to 1,068 codes
  • code to identify resistance to antimicrobial drugs (Z16.-)

Source: CMS ICD-10-CM Tabular List. How to read instructional notes.

Referenced in Other NotesGuidance

Instructional notes printed at other codes that name A51.39, its category, or a range that includes it.

Applicable To 1

These notes mention A51.39.

  • O98.1 Syphilis complicating pregnancy, childbirth and the puerperium
    Conditions in A50-A53 names A50-A53, which includes this code

Excludes1 1

These codes carry an Excludes1 note naming A51.39: they are not reported together with it, unless the two conditions are unrelated.

  • A52.79 Other symptomatic late syphilis
    syphilitic leukoderma (secondary) (A51.39)

Excludes2 1

These codes carry an Excludes2 note naming A51.39: its condition is not part of those codes, and both may be reported when the patient has both.

  • Block A65-A69 Other spirochetal diseases
    syphilis (A50-A53) names A50-A53, which includes this code

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR INF010
Sexually transmitted infections (excluding HIV and hepatitis)
Default principal diagnosis: inpatient Yes · outpatient Yes
CCSR SKN001
Skin and subcutaneous tissue infections
Default principal diagnosis: inpatient No · outpatient No

Patient EducationClinical

Skin Infections

Your skin is your body's largest organ. It has many different functions, including covering and protecting your body. It helps keep germs out. But sometimes the germs can cause a skin infection. It often happens when the germs enter your body through a break, cut, or wound on your skin.

The full article covers:

  • What are skin infections?
  • What causes skin infections?
  • Who is more likely to get a skin infection?
  • What are the symptoms of skin infections?
  • How are skin infections diagnosed?
  • How are skin infections treated?

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Convert A51.39 to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM
091.3 Secondary syph skin
Approximate The match is approximate rather than exact.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2026No changes
FY 2027CurrentCurrent code set, no changesEffective October 1, 2026 through September 30, 2027.

Questions About A51.39Overview

What is the ICD-10 code for other secondary syphilis of skin?

The ICD-10-CM code for other secondary syphilis of skin is A51.39 (sometimes written as A5139). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

Is A51.39 (Secondary syphilis of skin and mucous membranes) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report other secondary syphilis of skin on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

What MS-DRG does A51.39 group to?

When other secondary syphilis of skin is the principal diagnosis on an inpatient stay, it groups to MS-DRG 607, 606, with relative weights from 0.8772 to 1.5721 depending on complications. Higher weights mean higher Medicare reimbursement.

Is A51.39 a CC or MCC?

CMS lists A51.39 as a CC (complication or comorbidity) for FY 2027. Reported as a secondary diagnosis, it moves the inpatient stay to a higher-weighted DRG within its severity family. It does not count when the principal diagnosis is one of the 79 closely related codes in its exclusion list.

Can A51.39 be reported with A52.79?

Not as a rule. The Excludes1 note on A51.39 lists "late syphilitic leukoderma (A52.79)". An Excludes1 note means the excluded code is never reported together with this one; the only exception is when the two conditions are unrelated to each other (Official Guidelines, Section I.A.12.a).