All ICD10 Codes
Chapter 1

A00–B99: Certain Infectious and Parasitic Diseases

Certain Infectious and Parasitic Diseases diagnostic classification updated for 2026.

Chapter Instructions

Includes
  • diseases generally recognized as communicable or transmissible
Excludes1(Not coded here. Use a different code.)
  • certain localized infections - see body system-related chapters
Excludes2(Not included here. Code separately if applicable.)
  • carrier or suspected carrier of infectious disease (Z22.-)
  • 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
  • code to identify resistance to antimicrobial drugs (Z16.-)
All CodesBillable Only
Internal Codes
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  • A49.02—

    Methicillin resistant Staphylococcus aureus infection, unspecified site

  • A49.1—

    Streptococcal infection, unspecified site

  • A49.2—

    Hemophilus influenzae infection, unspecified site

  • A49.3—

    Mycoplasma infection, unspecified site

  • A49.8—

    Other bacterial infections of unspecified site

  • A49.9—

    Bacterial infection, unspecified

  • A50—

    Congenital syphilis

  • A50.0—

    Early congenital syphilis, symptomatic

  • 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

  • A50.09—

    Other early congenital syphilis, symptomatic

  • A50.1—

    Early congenital syphilis, latent

  • A50.2—

    Early congenital syphilis, unspecified

  • A50.3—

    Late congenital syphilitic oculopathy

  • A50.30—

    Late congenital syphilitic oculopathy, unspecified

  • A50.31—

    Late congenital syphilitic interstitial keratitis

  • A50.32—

    Late congenital syphilitic chorioretinitis

  • A50.39—

    Other late congenital syphilitic oculopathy

  • A50.4—

    Late congenital neurosyphilis [juvenile neurosyphilis]

  • A50.40—

    Late congenital neurosyphilis, unspecified

  • A50.41—

    Late congenital syphilitic meningitis

  • A50.42—

    Late congenital syphilitic encephalitis

  • A50.43—

    Late congenital syphilitic polyneuropathy

  • A50.44—

    Late congenital syphilitic optic nerve atrophy

  • A50.45—

    Juvenile general paresis

  • A50.49—

    Other late congenital neurosyphilis

  • A50.5—

    Other late congenital syphilis, symptomatic

  • A50.51—

    Clutton's joints

  • A50.52—

    Hutchinson's teeth

  • A50.53—

    Hutchinson's triad

  • A50.54—

    Late congenital cardiovascular syphilis

  • A50.55—

    Late congenital syphilitic arthropathy

  • A50.56—

    Late congenital syphilitic osteochondropathy

  • A50.57—

    Syphilitic saddle nose

  • A50.59—

    Other late congenital syphilis, symptomatic

  • A50.6—

    Late congenital syphilis, latent

  • A50.7—

    Late congenital syphilis, unspecified

  • A50.9—

    Congenital syphilis, unspecified

  • A51—

    Early syphilis

  • A51.0—

    Primary genital syphilis

  • A51.1—

    Primary anal syphilis

  • A51.2—

    Primary syphilis of other sites

  • A51.3—

    Secondary syphilis of skin and mucous membranes

  • A51.31—

    Condyloma latum

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