A18.4
Tuberculosis of skin and subcutaneous tissue
BillableComplete code, valid to report
Care settingsHome Health Primary · MMTA - Infectious Disease, Neoplasms, and Blood-Forming DiseasesHospital CC
A18.4 (also written A184) is a billable ICD-10-CM diagnosis code for tuberculosis of skin and subcutaneous tissue. It is part of the FY2027 code set, effective October 1, 2026. It is one of the 32 codes in category A18 (Tuberculosis of other organs). The Alphabetic Index lists it under 46 entries. Its coding notes include a Use additional code instruction, 7 Excludes1 entries and 7 Excludes2 entries.
Use additional code
Add the listed code as a secondary code, if known.
Excludes1
Not coded here. The listed conditions generally should not be reported together.
Also from chapter/block level (7 notes)
Inherited from A15–A19 Tuberculosis
- congenital tuberculosis (P37.0)
- nonspecific reaction to test for tuberculosis without active tuberculosis (R76.1-)
- pneumoconiosis associated with tuberculosis, any type in A15 (J65)
- positive PPD (R76.11)
- positive tuberculin skin test without active tuberculosis (R76.11)
- sequelae of tuberculosis (B90.-)
- silicotuberculosis (J65)
Excludes2
Not included here. Both codes may be reported if the patient has both conditions.
Also from chapter/block level (5 notes)
Inherited from Chapter 1 Certain infectious and parasitic diseases
- carrier or suspected carrier of infectious disease (Z22.-)
- certain localized infections - see body system-related chapters
- 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)
Care settings
How CMS programs treat this code. These are CMS claim edits and list entries, not coverage or eligibility rules.
Home Health Primary
Accepted as the primary (principal) diagnosis on a home health claim. The Home Health Grouper assigns it to the MMTA - Infectious Disease, Neoplasms, and Blood-Forming Diseases clinical group.
Source: CMS Home Health Grouper Software v07.2.26, effective October 1, 2026Hospital CC
Counts as a complication or comorbidity (CC) when reported as a secondary diagnosis on an inpatient claim. It does not count when the principal diagnosis is one of the 50 codes in its exclusion list. Some MS-DRGs also ignore a CC or MCC that defines the DRG.
Source: CMS MS-DRG Definitions Manual v44, effective October 1, 2026, Appendix CIncludes
Further defines or gives examples of the content of the category.
Inclusion terms
Conditions classified to this code.
This code
- Erythema induratum, tuberculous
- Lupus exedens
- Lupus vulgaris NOS
- Lupus vulgaris of eyelid
- Scrofuloderma
- Tuberculosis of external ear
Alphabetic Index terms
Terms the official Alphabetic Index lists for this code. 46 entries
- Acnitis (primary)
- Bazin's disease (primary) (tuberculous)
- Cellulitis (diffuse) (phlegmonous) (septic) (suppurative), tuberculous (primary)
- Erythema, erythematous (infectional) (inflammation), induratum (nontuberculous), tuberculous
- Erythema, erythematous (infectional) (inflammation), nodosum, tuberculous
- Erythema, erythematous (infectional) (inflammation), tuberculous (primary)
- Gumma (syphilitic), scrofulous (tuberculous)
- Gumma (syphilitic), tuberculous
- Lichen, scrofulosus (primary) (tuberculous)
- Lichenoides tuberculosis (primary)
- Lupus, exedens
- Lupus, tuberculous
Show 34 more
- Lupus, tuberculous, eyelid
- Lupus, vulgaris
- Lupus, vulgaris, eyelid
- Paronychia, tuberculous (primary)
- Scrofulide (primary) (tuberculous)
- Scrofuloderma, scrofulodermia (any site) (primary)
- Scrofulosus lichen (primary) (tuberculous)
- Tarsitis (eyelid), tuberculous
- Tuberculid, tuberculide (indurating, subcutaneous) (lichenoid) (miliary) (papulonecrotic) (primary) (skin)
- Tuberculosis, tubercular, tuberculous (calcification) (calcified) (caseous) (chromogenic acid-fast bacilli) (degeneration) (fibrocaseous) (fistula) (interstitial) (isolated circumscribed lesions) (necrosis) (parenchymatous) (ulcerative), abscess (respiratory), skin (primary)
- Tuberculosis, tubercular, tuberculous (calcification) (calcified) (caseous) (chromogenic acid-fast bacilli) (degeneration) (fibrocaseous) (fistula) (interstitial) (isolated circumscribed lesions) (necrosis) (parenchymatous) (ulcerative), cellulitis (primary)
- Tuberculosis, tubercular, tuberculous (calcification) (calcified) (caseous) (chromogenic acid-fast bacilli) (degeneration) (fibrocaseous) (fistula) (interstitial) (isolated circumscribed lesions) (necrosis) (parenchymatous) (ulcerative), colliquativa (primary)
- Tuberculosis, tubercular, tuberculous (calcification) (calcified) (caseous) (chromogenic acid-fast bacilli) (degeneration) (fibrocaseous) (fistula) (interstitial) (isolated circumscribed lesions) (necrosis) (parenchymatous) (ulcerative), cutis (colliquativa) (primary)
- Tuberculosis, tubercular, tuberculous (calcification) (calcified) (caseous) (chromogenic acid-fast bacilli) (degeneration) (fibrocaseous) (fistula) (interstitial) (isolated circumscribed lesions) (necrosis) (parenchymatous) (ulcerative), ear (inner) (middle), external (primary)
- Tuberculosis, tubercular, tuberculous (calcification) (calcified) (caseous) (chromogenic acid-fast bacilli) (degeneration) (fibrocaseous) (fistula) (interstitial) (isolated circumscribed lesions) (necrosis) (parenchymatous) (ulcerative), ear (inner) (middle), skin (primary)
- Tuberculosis, tubercular, tuberculous (calcification) (calcified) (caseous) (chromogenic acid-fast bacilli) (degeneration) (fibrocaseous) (fistula) (interstitial) (isolated circumscribed lesions) (necrosis) (parenchymatous) (ulcerative), erythema (induratum) (nodosum) (primary)
- Tuberculosis, tubercular, tuberculous (calcification) (calcified) (caseous) (chromogenic acid-fast bacilli) (degeneration) (fibrocaseous) (fistula) (interstitial) (isolated circumscribed lesions) (necrosis) (parenchymatous) (ulcerative), eyelid (primary) (lupus)
- Tuberculosis, tubercular, tuberculous (calcification) (calcified) (caseous) (chromogenic acid-fast bacilli) (degeneration) (fibrocaseous) (fistula) (interstitial) (isolated circumscribed lesions) (necrosis) (parenchymatous) (ulcerative), indurativa (primary)
- Tuberculosis, tubercular, tuberculous (calcification) (calcified) (caseous) (chromogenic acid-fast bacilli) (degeneration) (fibrocaseous) (fistula) (interstitial) (isolated circumscribed lesions) (necrosis) (parenchymatous) (ulcerative), lichenoides (primary)
- Tuberculosis, tubercular, tuberculous (calcification) (calcified) (caseous) (chromogenic acid-fast bacilli) (degeneration) (fibrocaseous) (fistula) (interstitial) (isolated circumscribed lesions) (necrosis) (parenchymatous) (ulcerative), lupus vulgaris
- Tuberculosis, tubercular, tuberculous (calcification) (calcified) (caseous) (chromogenic acid-fast bacilli) (degeneration) (fibrocaseous) (fistula) (interstitial) (isolated circumscribed lesions) (necrosis) (parenchymatous) (ulcerative), papulonecrotic (a) (primary)
- Tuberculosis, tubercular, tuberculous (calcification) (calcified) (caseous) (chromogenic acid-fast bacilli) (degeneration) (fibrocaseous) (fistula) (interstitial) (isolated circumscribed lesions) (necrosis) (parenchymatous) (ulcerative), paronychia (primary)
- Tuberculosis, tubercular, tuberculous (calcification) (calcified) (caseous) (chromogenic acid-fast bacilli) (degeneration) (fibrocaseous) (fistula) (interstitial) (isolated circumscribed lesions) (necrosis) (parenchymatous) (ulcerative), skin (any site) (primary)
- Tuberculosis, tubercular, tuberculous (calcification) (calcified) (caseous) (chromogenic acid-fast bacilli) (degeneration) (fibrocaseous) (fistula) (interstitial) (isolated circumscribed lesions) (necrosis) (parenchymatous) (ulcerative), subcutaneous tissue (cellular) (primary)
- Tuberculosis, tubercular, tuberculous (calcification) (calcified) (caseous) (chromogenic acid-fast bacilli) (degeneration) (fibrocaseous) (fistula) (interstitial) (isolated circumscribed lesions) (necrosis) (parenchymatous) (ulcerative), subcutis (primary)
- Tuberculosis, tubercular, tuberculous (calcification) (calcified) (caseous) (chromogenic acid-fast bacilli) (degeneration) (fibrocaseous) (fistula) (interstitial) (isolated circumscribed lesions) (necrosis) (parenchymatous) (ulcerative), tarsitis
- Tuberculosis, tubercular, tuberculous (calcification) (calcified) (caseous) (chromogenic acid-fast bacilli) (degeneration) (fibrocaseous) (fistula) (interstitial) (isolated circumscribed lesions) (necrosis) (parenchymatous) (ulcerative), ulcer (skin) (primary)
- Tuberculosis, tubercular, tuberculous (calcification) (calcified) (caseous) (chromogenic acid-fast bacilli) (degeneration) (fibrocaseous) (fistula) (interstitial) (isolated circumscribed lesions) (necrosis) (parenchymatous) (ulcerative), verruca, verrucosa (cutis) (primary)
- Ulcer, ulcerated, ulcerating, ulceration, ulcerative, skin (atrophic) (chronic) (neurogenic) (non-healing) (perforating) (pyogenic) (trophic) (tropical), tuberculous (primary)
- Ulcus, cutis tuberculosum
- Verruca (due to HPV) (filiformis) (simplex) (viral) (vulgaris), necrogenica (primary) (tuberculosa)
- Verruca (due to HPV) (filiformis) (simplex) (viral) (vulgaris), tuberculosa (primary)
- Wart (due to HPV) (filiform) (infectious) (viral), prosector (tuberculous)
- Wart (due to HPV) (filiform) (infectious) (viral), tuberculous