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A18.4 ICD-10-CA code: Tuberculosis of skin and subcutaneous tissue

A18.4 is the ICD-10-CA code for “Tuberculosis of skin and subcutaneous tissue” in CIHI’s FY 2026–2027 release, in effect from Apr 1, 2026.

Official description

A18.4

Tuberculosis of skin and subcutaneous tissue

Short description: TB skin and subcutaneous tissue

ICD-10-CA · Canada · Also written A184

Index terms

Entries in CIHI’s alphabetical index that lead to A18.4. Searching the index by the condition the note names is how coders reach this code.

  • Lupus, exedens
  • Lupus, vulgaris
  • Acnitis (primary)
  • Lupus, tuberculous
  • Ulcus, cutis tuberculosum
  • Gumma (syphilitic), tuberculous
  • Lichenoides tuberculosis (primary)
  • Scrofulide (primary) (tuberculous)
  • Bazin's disease (primary) (tuberculous)
  • Scrofulosus lichen (primary) (tuberculous)
  • Lichen, scrofulosus (primary) (tuberculous)
  • Erythema, erythematous, nodosum, tuberculous
  • Gumma (syphilitic), scrofulous (tuberculous)
  • Erythema, erythematous, tuberculous (primary)
  • Scrofuloderma, scrofulodermia (any site) (primary)
  • Paronychia (with lymphangitis), tuberculous (primary)
  • Cellulitis (diffuse) (with lymphangitis), tuberculous (primary)
  • Erythema, erythematous, induratum (nontuberculous), tuberculous
  • Wart (common) (digitate) (filiform) (infectious) (juvenile) (plantar) (viral), tuberculous
  • Tuberculosis, tubercular, tuberculous (caseous) (degeneration) (gangrene) (necrosis), lupus vulgaris
  • Wart (common) (digitate) (filiform) (infectious) (juvenile) (plantar) (viral), prosector (tuberculous)
  • Tuberculosis, tubercular, tuberculous (caseous) (degeneration) (gangrene) (necrosis), subcutis (primary)
  • Tuberculid, tuberculide (indurating, subcutaneous) (lichenoid) (miliary) (papulonecrotic) (primary) (skin)
  • Tuberculosis, tubercular, tuberculous (caseous) (degeneration) (gangrene) (necrosis), cellulitis (primary)
  • Tuberculosis, tubercular, tuberculous (caseous) (degeneration) (gangrene) (necrosis), indurativa (primary)
  • Tuberculosis, tubercular, tuberculous (caseous) (degeneration) (gangrene) (necrosis), paronychia (primary)
  • Tuberculosis, tubercular, tuberculous (caseous) (degeneration) (gangrene) (necrosis), lichenoides (primary)
  • Tuberculosis, tubercular, tuberculous (caseous) (degeneration) (gangrene) (necrosis), colliquativa (primary)
  • Tuberculosis, tubercular, tuberculous (caseous) (degeneration) (gangrene) (necrosis), ulcer (primary) (skin)
  • Verruca (filiformis) (plana) (plana juvenilis) (plantaris) (simplex) (viral) (vulgaris), tuberculosa (primary)
  • Tuberculosis, tubercular, tuberculous (caseous) (degeneration) (gangrene) (necrosis), skin (any site) (primary)
  • Tuberculosis, tubercular, tuberculous (caseous) (degeneration) (gangrene) (necrosis), papulonecrotic(a) (primary)
  • Tuberculosis, tubercular, tuberculous (caseous) (degeneration) (gangrene) (necrosis), cutis (colliquativa) (primary)
  • Tuberculosis, tubercular, tuberculous (caseous) (degeneration) (gangrene) (necrosis), ear (inner) (middle), skin (primary)
  • Tuberculosis, tubercular, tuberculous (caseous) (degeneration) (gangrene) (necrosis), verruca, verrucosa (cutis) (primary)
  • Verruca (filiformis) (plana) (plana juvenilis) (plantaris) (simplex) (viral) (vulgaris), necrogenica (primary) (tuberculosa)
  • Tuberculosis, tubercular, tuberculous (caseous) (degeneration) (gangrene) (necrosis), ear (inner) (middle), external (primary)
  • Tuberculosis, tubercular, tuberculous (caseous) (degeneration) (gangrene) (necrosis), erythema (induratum) (nodosum) (primary)
  • Tuberculosis, tubercular, tuberculous (caseous) (degeneration) (gangrene) (necrosis), subcutaneous tissue (cellular) (primary)
  • Tuberculosis, tubercular, tuberculous (caseous) (degeneration) (gangrene) (necrosis), abscess NEC (respiratory), skin (primary)
  • Ulcer, ulcerated, ulcerating, ulceration, ulcerative, skin (atrophic) (chronic) (neurogenic) (perforating) (pyogenic) (trophic), tuberculous (primary)

Notes for A18.4

As CIHI prints them, with any note A18.4 takes from the headings above it.

Includes

  • Erythema induratum, tuberculousLupus:• exedens• vulgaris• NOS• of eyelid† (H03.1*)Scrofuloderma
  • Infections due to Mycobacterium tuberculosis and Mycobacterium bovisFrom A15-A19 Tuberculosis
  • Diseases generally recognized as communicable or transmissibleFrom Chapter 1: Certain infectious and parasitic diseases (A00-B99)

Use additional code

Add a code for this detail when the note documents it.

  • Use additional code (U82-U84) to identify resistance to antimicrobial drugsFrom Chapter 1: Certain infectious and parasitic diseases (A00-B99)

Excludes

Conditions classified elsewhere.

  • Lupus erythematosus (L93.-):• systemic (M32.-)
  • Congenital tuberculosis (P37.0)pneumoconiosis associated with tuberculosis (J65)sequelae of tuberculosis (B90.-)silicotuberculosis (J65)From A15-A19 Tuberculosis
  • Carrier or suspected carrier of infectious disease (Z22.-)certain localized infections - see body system-related chaptersinfectious and parasitic diseases:• complicating pregnancy, childbirth and the puerperium [except obstetrical tetanus] (O98.-)• specific to the perinatal period [except tetanus neonatorum, whooping cough, congenital syphilis, perinatal gonococcal infection and perinatal human immunodeficiency virus [HIV] disease] (P35-P39)influenza and other acute respiratory infections (J00-J22)From Chapter 1: Certain infectious and parasitic diseases (A00-B99)

Where A18.4 sits

  1. 1ChapterChapter 1: Certain infectious and parasitic diseases (A00-B99)
  2. 2Block A15-A19Tuberculosis
  3. 3Category A18Tuberculosis of other organs
  4. 4Valid code A18.4Tuberculosis of skin and subcutaneous tissue

Source and release

Data release
ICD-10-CA · FY 2026–2027
Effective date
Apr 1, 2026
Publisher
CIHI

This page is built from the ICD-10-CA catalog that Vero Codes reads when it suggests codes: Canadian Institute for Health Information’s FY 2026–2027 release, imported from the publisher’s file and checked against it. The description, notes and structured data come from the same record.

See A18.4 in the CIHI source

Frequently asked questions

What does ICD-10-CA code A18.4 mean?

A18.4 is the ICD-10-CA code for “Tuberculosis of skin and subcutaneous tissue” in CIHI’s ICD-10-CA FY 2026–2027 release.

Where is A18.4 in ICD-10-CA?

A18.4 sits under A18 Tuberculosis of other organs, within A15-A19 Tuberculosis, within Chapter 1: Certain infectious and parasitic diseases (A00-B99).

What coding notes apply to A18.4?

ICD-10-CA lists Includes, Excludes, Use additional code notes for A18.4, including those from the headings it sits under. They are listed on this page with where each one comes from.

Which ICD-10-CA release does this page use?

It uses CIHI’s FY 2026–2027 release, in effect from Apr 1, 2026 to Mar 31, 2027. It is a reference: confirm the code against the current list and the payer’s rules before you submit it.

Codes beside A18.4

A18.0Tuberculosis of bones and jointsA18.1Tuberculosis of genitourinary systemA18.2Tuberculous peripheral lymphadenopathyA18.3Tuberculosis of intestines, peritoneum and mesenteric lymph nodesA18.5Tuberculosis of eyeA18.6Tuberculosis of earA18.7Tuberculosis of adrenal glandsA18.8Tuberculosis of other specified organs