ICD-10 code A65: Nonvenereal syphilis (bejel) coding guide

Key Takeaways

ICD-10 code A65 is the billable, specific diagnosis code for nonvenereal syphilis (bejel/endemic syphilis) valid for 2026 reimbursement claims.

A65 falls under the A65-A69 category (Other spirochetal diseases) within Chapter 1: Certain infectious and parasitic diseases (A00-B99).

Accurate documentation must distinguish nonvenereal from venereal syphilis (A50-A53) – confusing the two leads to claim denials and compliance risk.

Practice management software like Pabau, including its claims management and digital intake tools, helps infectious disease and dermatology practices code A65 encounters accurately from intake through billing.

ICD-10 code A65 is the billable diagnosis code for nonvenereal syphilis, a Treponema-caused infection transmitted through non-sexual, skin-to-skin contact. It differs from venereal syphilis in pathogen subspecies, transmission route, and chapter placement, though the two conditions can look similar enough on presentation to create documentation confusion.

Travel medicine practices, dermatology practices treating patients from endemic regions, and sexual health providers encounter A65 most often.

This reference covers the ICD-10 code A65 definition and classification hierarchy, billable status for 2026, synonyms and inclusions, the A65-A69 code range, related and differential codes, documentation requirements, and practical coding notes for practices. Understanding how to distinguish and document this condition accurately reduces denial risk and supports audit-ready records.

ICD-10 code A65: Definition and code description

ICD-10 code A65 describes nonvenereal syphilis, a chronic bacterial infection caused by Treponema pallidum subspecies endemicum. It is distinct from venereal syphilis (caused by T. pallidum subspecies pallidum) in its mode of transmission, affected populations, and geographic distribution. The World Health Organization classifies it under the broader treponematoses group alongside yaws (A66) and pinta (A67).

The condition is also widely known as bejel or endemic syphilis. It predominantly affects children in dry, arid regions of sub-Saharan Africa, the Middle East, and parts of Central Asia, spreading through direct skin-to-skin or mucous membrane contact rather than sexual transmission.

Clinicians in dermatology practices, or those using sexual health clinic software, should consider A65 in the differential when a patient’s syphilis-like presentation lacks the sexual transmission history expected for venereal forms.

Billable status for ICD-10 code A65

A65 is a billable and specific ICD-10-CM code valid for reimbursement in fiscal year 2026. It can be used directly on claims to indicate a confirmed diagnosis of nonvenereal syphilis without requiring a more granular subcategory.

This is a key practical distinction from several adjacent codes in the A65-A69 range, such as A69.2 (Lyme disease), which are non-billable parent codes requiring subcategory selection before claim submission.

Classification hierarchy for ICD-10 code A65

Understanding where A65 sits in the ICD-10-CM hierarchy prevents misrouting to the sexually transmitted infection (STI) chapter, which is a common documentation error. The WHO’s international ICD-10 browser confirms the following hierarchy for this code:

• Chapter 1: Certain infectious and parasitic diseases (A00-B99)
• Block: A65-A69 – Other spirochetal diseases
• Category: A65 – Nonvenereal syphilis (no subcategories; A65 is the complete, billable code)

The block A65-A69 sits immediately after A50-A64 (infections with a predominantly sexual mode of transmission). This adjacency is intentional in the ICD-10 structure: treponematoses that were historically confused with sexually transmitted infections are grouped nearby but kept distinct. Coders working in dermatology EMR software environments should configure their code selection screens to distinguish these blocks clearly.

Synonyms and inclusions for A65

ICD-10 code A65 includes several synonyms and inclusion terms. Knowing these matters because clinical notes often use the local or regional name for the condition rather than the ICD-10 official descriptor. Any of the following terms on a clinical note maps to A65 for coding purposes:

• Bejel – the most commonly used clinical synonym, particularly in Middle Eastern and African clinical literature
• Endemic syphilis – used in epidemiological and public health contexts
• Nonvenereal childhood syphilis – emphasizes the typical age of onset and non-sexual acquisition
• Treponema endemicum infection – the pathogen-specific descriptor sometimes used in laboratory reports

Coders should flag any of these terms in clinical notes as mapping to A65. If a note says “bejel confirmed” or “endemic syphilis consistent with travel history,” A65 is the correct code. For practices managing high-volume digital intake forms that include travel and exposure history fields, capturing this data at intake supports accurate code selection downstream.

The A65-A69 ICD-10 code range: Other spirochetal diseases

A65 is the first code in the A65-A69 block. Understanding the full range helps coders identify when A65 is appropriate versus when a different spirochetal disease code applies. The AAPC Codify ICD-10-CM lookup provides the complete block listing, summarized below:

A65 stands out as the only single-code, directly billable entry in this block. All other categories (A66-A69) require the coder to drill into subcategories. This makes ICD-10 code A65 administratively simpler to submit than its neighbouring spirochetal codes, though the clinical documentation requirements are the same.

Clinical overview and differential coding: ICD-10 code A65 vs venereal syphilis

The most consequential coding decision around A65 is distinguishing it from the A50-A53 venereal syphilis range. Assigning the wrong code creates downstream problems: incorrect epidemiological reporting, payer audits, and potential HIPAA-related compliance documentation issues. The distinction rests on three documented clinical factors.

Pathogen and transmission route

Nonvenereal syphilis (A65) is caused by Treponema pallidum subspecies endemicum. Venereal syphilis (A51-A53) is caused by T. pallidum subspecies pallidum. Standard serological tests (RPR, VDRL, TPHA) cannot reliably distinguish between subspecies because all three treponematoses produce cross-reactive antibodies. The clinical note must document the transmission route (non-sexual skin-to-skin or mucous membrane contact) and geographic or epidemiological context to justify A65.

Clinical presentation differences

Bejel typically presents in a three-stage progression distinct from venereal syphilis. Early stage: mucocutaneous patches around the mouth and oropharynx, often in children. Secondary stage: widespread papules and condylomata-like lesions on the trunk and extremities.

Late stage: gummatous lesions affecting skin, bone, and cartilage, sometimes causing destructive rhinopharyngitis (gangosa). Cardiovascular and neurological late-stage manifestations, which are characteristic of venereal syphilis, are uncommon in bejel. Documenting the specific lesion type, location, and stage in the clinical note substantiates A65 coding.

Geographic and demographic context

A65 is endemic in arid rural communities of sub-Saharan Africa (particularly the Sahel belt), parts of the Middle East, and isolated communities in Central Asia. Practices with patient populations from these regions, or travel medicine practices evaluating returning travelers, are the most likely clinical settings for ICD-10 code A65 encounters.

Capturing country of origin and travel history in the patient record is not optional; it is the primary evidentiary support for the code. Practices using skin clinic software with structured clinical notes can template this documentation into their encounter workflows.

Documentation requirements for A65 claims

Payer audits on infectious disease codes increasingly focus on whether the clinical record supports the specific code submitted rather than a related but less precise alternative. For ICD-10 code A65, the documentation checklist should include all of the following elements before the claim is generated.

Our guide to clinical documentation software covers tools built to enforce checklists like this one at the point of care.

• Confirmed or suspected diagnosis statement: The provider must explicitly state “nonvenereal syphilis,” “bejel,” or “endemic syphilis” in the assessment or impression section of the note. Using only “syphilis” or “treponematosis, unspecified” will not support A65 on audit.
• Transmission route documentation: The note must record the absence of sexual transmission risk and the presence of contact-based or community exposure. Reference the patient’s country of origin or travel history to an endemic region.
• Lesion description and stage: Document the specific mucocutaneous, papular, or gummatous lesions observed. Note anatomical location and whether the presentation is consistent with early, secondary, or late bejel.
• Serology results: Record any RPR, VDRL, or TPHA results and note that serological positivity is consistent with treponematosis but cannot alone confirm subspecies. The clinical and epidemiological context determines the specific code.
• Differential diagnosis consideration: For audit-readiness, the note should briefly address why venereal syphilis (A51-A53) was excluded, referencing the non-sexual transmission history and endemic region context.

Practices managing these encounters through patient records management systems that support structured clinical notes can template these five documentation elements into their infectious disease encounter workflows. This reduces the risk of submitting A65 without the supporting documentation that payers expect.

Related codes and crosswalk for ICD-10 code A65

Coders working with A65 need familiarity with several adjacent and related codes. The CDC/NCHS ICD-10-CM web tool is the authoritative lookup for confirming current billable status and hierarchical relationships. Below are the codes most commonly encountered in the same clinical context as A65.

Within the A65-A69 block

• A66 (Yaws): Caused by T. pallidum subspecies pertenue. Tropical rather than arid endemic distribution. Uses subcategories A66.0-A66.9 for granulomatous lesions, bone involvement, and late stages. Not directly billable at the A66 level.
• A67 (Pinta/Carate): Caused by Treponema carateum. Limited to Latin America. Primarily dermatological (pigmentation changes). Uses subcategories A67.0-A67.9.
• A68 (Relapsing fevers): Caused by Borrelia species, not Treponema. Included in the spirochetal block but clinically and pathologically distinct from treponematoses. A68.0 (louse-borne) and A68.1 (tick-borne) are the billable subcategories.
• A69.9 (Spirochetal infection, unspecified): The catch-all for spirochetal infections that cannot be more precisely identified. Use only when the clinical record genuinely cannot support a more specific code. A69.9 is billable but lower specificity than A65.

Venereal syphilis codes (differential context)

• A51 (Primary syphilis): Chancre-stage venereal infection; further specified by anatomical site (A51.0 genital, A51.1 anal, A51.2 other).
• A52 (Late syphilis): Tertiary venereal syphilis including cardiovascular (A52.0x) and neurosyphilis (A52.1x-A52.3) complications. These late-stage complications are distinct from bejel’s late presentations.
• A53 (Other and unspecified syphilis): Includes A53.0 (latent syphilis, unspecified) and A53.9 (syphilis, unspecified). If a treponematosis cannot be specified as venereal or nonvenereal, A53.9 may be considered, though this should be avoided when clinical context supports A65.

Coders managing other infectious disease diagnoses may also encounter ICD-10 code A55 (chlamydial lymphogranuloma venereum), which sits in the adjoining A50-A64 sexually transmitted block and follows similar documentation logic. ICD-10 code A70 (Chlamydia psittaci infections) shows how Chapter 1 extends well beyond the treponematoses covered here.

ICD-9-CM crosswalk

For practices reviewing historical claims or dealing with legacy payer systems, ICD-10 code A65 maps from ICD-9-CM code 104.0 (Nonvenereal endemic syphilis). The transition to ICD-10 in October 2015 did not change the clinical definition, only the classification system. Claims submitted before October 1, 2015 using 104.0 are equivalent to post-2015 A65 submissions.

Coding notes and guidelines for ICD-10 code A65

The CMS ICD-10-CM guidelines and the NCHS Official Guidelines for Coding and Reporting provide the framework for applying A65 correctly. Several practical notes apply specifically to this code.

Recently published guides cover similar billable, single-code diagnoses and their documentation patterns, including ICD-10 code A33 (tetanus neonatorum), ICD-10 code I40.0 (infective myocarditis), and ICD-10 code N37 (urethral disorders).

No excludes notes for A65

Unlike some codes in the infectious disease chapter, A65 carries no Type 1 Excludes or Type 2 Excludes notes in the 2026 ICD-10-CM tabular list. This means A65 can be coded alongside other diagnosis codes from the same encounter without restriction from the code itself. However, clinical documentation must still support each code submitted on the same claim.

Principal versus secondary diagnosis

A65 is most often the principal diagnosis when the encounter is specifically for evaluation and management of the spirochetal infection. It becomes a secondary diagnosis when the patient presents for a different primary complaint and the nonvenereal syphilis is a comorbidity documented and addressed during the encounter.

Sequencing follows the general ICD-10-CM sequencing guidelines: the condition primarily responsible for the visit goes first.

Combining with procedure and evaluation codes

A65 is a diagnosis code only and must be paired with appropriate CPT or HCPCS procedure codes on the claim. Typical accompanying codes include an established-patient E/M code such as CPT code 99214, a dermatology procedure code such as CPT code 10021 for biopsy or lesion assessment, and laboratory codes for serology.

Practices using claims management software can configure code pairing rules to flag encounters with A65 that lack a corresponding E/M or procedure code before submission.

Mandatory reporter considerations

Nonvenereal syphilis (bejel) is not a nationally notifiable condition in the United States under current CDC reporting requirements, unlike venereal syphilis, which is notifiable. However, state-level reporting requirements vary, and some jurisdictions may require reporting of any confirmed treponematosis.

Clinicians should verify local public health reporting obligations when diagnosing A65. Practices supporting compliance management workflows should include a state-specific reporting checklist within their infectious disease encounter protocol. Our roundup of HIPAA compliance software covers additional tools for building that checklist into daily workflows.

How Pabau supports accurate A65 coding workflows

Infectious disease coding accuracy depends on two things happening consistently: structured data capture at the point of care, and workflow checkpoints before claim submission. Both break down in practices relying on free-text notes and manual coding review.

Pabau’s dermatology intake form template allows practices to build structured travel history and exposure history fields into their patient onboarding process. Practices without a specialty-specific starting point can adapt a new client intake form template instead.

For any infectious disease encounter, a patient arriving from an A65-endemic region will have that geographic context captured in a queryable field rather than buried in a free-text paragraph. That structured data flows into the clinical note, making code selection defensible at audit.

On the billing side, Pabau’s claims management software supports code-pairing validation, so an A65 diagnosis submitted without a corresponding E/M or procedure code triggers a pre-submission alert rather than a post-submission denial. See our medical billing guide for how this fits into the wider claims cycle.

For dermatology practices, sexual health practices, and travel medicine providers who encounter nonvenereal spirochetal infections, this kind of front-end validation reduces rework. See how it fits your workflow by booking a demo.

Conclusion

ICD-10 code A65 is a specific, billable code for nonvenereal syphilis (bejel) that requires careful clinical documentation to distinguish from the venereal syphilis range (A51-A53). The key documentation anchors are: an explicit diagnosis statement using A65’s accepted synonyms, a documented non-sexual transmission history with geographic context, lesion description with stage, and serology results placed in clinical context.

For practices that see patients from A65-endemic regions, building these documentation elements into structured encounter templates prevents audit exposure and supports accurate epidemiological reporting. Pabau’s patient records management and clinical documentation tools are built to support exactly this kind of structured coding workflow across dermatology, sexual health, and travel medicine settings.

Continue your research

Need guidance on coding other infectious and parasitic disease diagnoses? ICD-10 code B09 covers unspecified viral infections with skin lesions, a documentation pattern that shares bejel’s mucocutaneous presentation.

Looking for dermatology-specific software to support coding workflows? Best dermatology EMR software from Pabau supports structured clinical notes, pre-submission claim validation, and integrated patient records for skin and infectious disease encounters.

Want to build audit-ready clinical documentation into your practice? Clinical documentation best practices for healthcare practices covers how digital forms and structured intake workflows reduce coding errors and support compliance.

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