A55Billable, valid for claims from October 1, 2026

Chlamydial lymphogranuloma (venereum)

In Infections with a predominantly sexual mode of transmission (A50-A64), chapter 1: Certain Infectious and Parasitic Diseases

  • A55 is billable and valid on claims for FY 2027. If the record has more detail, check the other codes under A50-A64 below.
  • As a secondary diagnosis it is not a CC or MCC, so it doesn't raise the MS-DRG payment.
  • Doesn't count toward a Medicare Advantage risk score (no HCC in V28).
  • AHRQ's Chronic Condition Indicator classes it as not chronic (an acute or short-term condition).

Also indexed as: Bubo, climatic; Bubo, inguinal, climatic; Bubo, tropical; Disease, Durand-Nicholas-Favre; Disease, Favre-Durand-Nicolas; Disease, Frei's; Disease, Nicolas-Favre; Disease, venereal, fifth; Disease, venereal, sixth; Durand-Nicolas-Favre disease; Esthiomene; Fifth disease, venereal; Frei's disease; Genito-anorectal syndrome; Infection, Chlamydia, chlamydial, lymphogranuloma; Lymphadenitis, due to, chlamydial lymphogranuloma; Lymphadenitis, due to, lymphogranuloma venereum; Lymphadenitis, venereal; Lymphogranuloma, chlamydial; Lymphogranuloma, inguinale; Lymphogranuloma, venereum; Lymphopathia venereum; Nicolas-Favre disease; Poradenitis; Stricture, rectum, due to, chlamydial lymphogranuloma; Stricture, rectum, due to, lymphogranuloma venereum; Stricture, rectum, inflammatory; Syndrome, genito-anorectal; Venereal, bubo; Venereal, lymphogranuloma

Advertisements

Instructional notes

Includes: conditions that are coded here

  • Climatic or tropical bubo
  • Durand-Nicolas-Favre disease
  • Esthiomene
  • Lymphogranuloma inguinale

Also applies, from Infections with a predominantly sexual mode of transmission (A50-A64)

These notes sit on A50-A64 and apply to every code under it, including A55.

Excludes1: not coded here, use a different code

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

Excludes2: not included here, code separately if applicable

  • human immunodeficiency virus [HIV] disease (B20)

Official coding guidelines

From the ICD-10-CM Official Guidelines for Coding and Reporting, FY 2027 (CMS and NCHS). Links open the PDF at the right page.

Rules for coding infections and parasitic diseases, including HIV, organism and drug resistance codes, sepsis and septic shock, MRSA, Zika, and COVID-19.

Read Section I.C.1 (page 19)

Related conditions

Grouped by AHRQ's Clinical Classifications Software Refined (CCSR), which sorts every diagnosis code into clinically meaningful categories.

A55 is in Sexually transmitted infections (excluding HIV and hepatitis) (INF010, its default category), with 160 codes. Others in it:

  • A50.01 Early congenital syphilitic oculopathy
  • A50.02 Early congenital syphilitic osteochondropathy
  • A50.03 Early congenital syphilitic pharyngitis
  • A50.04 Early congenital syphilitic pneumonia
  • A50.05 Early congenital syphilitic rhinitis
  • A50.06 Early cutaneous congenital syphilis
  • A50.07 Early mucocutaneous congenital syphilis
  • A50.08 Early visceral congenital syphilis

Medicare coverage articles listing A55

This Medicare billing and coding article lists A55 as a diagnosis that supports medical necessity for the services they cover. From the CMS Medicare Coverage Database; check your own contractor's article before billing.

Other codes that refer to A55

Notes on these codes point to A55.

  • A56 Excludes2: chlamydial lymphogranuloma (A55)
  • A70-A74 Excludes1: sexually transmitted chlamydial diseases (A55-A56)
  • A74 Excludes1: sexually transmitted chlamydial diseases (A55-A56)
  • O98.3 Includes: Conditions in A55-A64

About the condition

Plain-language background from MedlinePlus (National Library of Medicine), not coding guidance.

Chlamydia Infections

Chlamydia is a common sexually transmitted infection (STI). It is caused by bacteria called Chlamydia trachomatis. Anyone can get chlamydia. It often doesn't cause symptoms, so people may not know that they have it. Antibiotics can cure it. But if it's not treated, chlamydia can cause serious health problems.

Read more about chlamydia infections on MedlinePlus

Code history

Valid since FY2016, when ICD-10-CM took effect on October 1, 2015. No changes since.

ICD-9-CM equivalent

Legacy crosswalk from the CMS General Equivalence Mappings (last updated 2018).

  • 099.1 Lymphogranuloma venereum
ICD-9 to ICD-10 converter