A56.4 Chlamydial infection of pharynx

Billable ICD-10-CM code, FY2026.

Applies from A56 Other sexually transmitted chlamydial diseases

Includes

• sexually transmitted diseases due to Chlamydia
• trachomatis

Excludes1 (never code together)

• neonatal chlamydial conjunctivitis (P39.1)
• neonatal chlamydial pneumonia (P23.1)

Excludes2 (not included here)

• chlamydial lymphogranuloma (A55)
• conditions classified to A74.-

MS-DRG index

Defines the logic of DRG(s) 011-013 in MDC PRE.

Approximate ICD-9-CM (GEMs)

• 099.51 Other venereal diseases due to chlamydia trachomatis, pharynx

Code annotations containing back-references to A56.4

Back-references to A56

• Type 1 Excludes: A74 Other diseases caused by chlamydiae ("sexually transmitted chlamydial diseases (A55-A56)")
• Type 2 Excludes: N34 Urethritis and urethral syndrome ("urethritis in diseases with a predominantly sexual mode of transmission (A50-A64)")

Diagnosis Index entries for A56.4

• Chlamydia, chlamydial › pharyngitis
• Disease, diseased › venereal › chlamydial NEC › pharynx
• Infection, infected, infective (opportunistic) › Chlamydia, chlamydial › pharynx
• Pharyngitis (acute) (catarrhal)(gangrenous) (infective) (malignant) (membranous) (phlegmonous) (pseudomembranous) (simple) (subacute) (suppurative) (ulcerative) (viral) › chlamydial

Nearby codes

• A56.1 Chlamydial infection of pelviperitoneum and other genitourinary organs
• A56.11 Chlamydial female pelvic inflammatory disease
• A56.19 Other chlamydial genitourinary infection
• A56.2 Chlamydial infection of genitourinary tract, unspecified
• A56.3 Chlamydial infection of anus and rectum
• A56.4 Chlamydial infection of pharynx (this code)
• A56.8 Sexually transmitted chlamydial infection of other sites