A18.4 Tuberculosis of skin and subcutaneous tissue

Billable ICD-10-CM code, FY2026. Acts as a Complication or Comorbidity (CC) as a secondary diagnosis.

Applicable to

• Erythema induratum, tuberculous
• Lupus exedens
• Lupus vulgaris NOS
• Lupus vulgaris of eyelid
• Scrofuloderma
• Tuberculosis of external ear

Excludes2 (not included here)

• lupus erythematosus (L93.-)
• systemic lupus erythematosus (M32.-)

MS-DRG index

Defines the logic of DRG(s) 606-607 in MDC 09.

Approximate ICD-9-CM (GEMs)

• 017.00 Tuberculosis of skin and subcutaneous cellular tissue, unspecified (approximate)
• 017.10 Erythema nodosum with hypersensitivity reaction in tuberculosis, unspecified (approximate)

Code annotations containing back-references to A18.4

Back-references to A18.4

• Type 2 Excludes: A18.5 Tuberculosis of eye ("lupus vulgaris of eyelid (A18.4)")
• Type 2 Excludes: A18.6 Tuberculosis of (inner) (middle) ear ("tuberculosis of external ear (A18.4)")
• Type 1 Excludes: L52 Erythema nodosum ("tuberculous erythema nodosum (A18.4)")
• Type 1 Excludes: L93 Lupus erythematosus ("lupus exedens (A18.4)")
• Type 1 Excludes: L93 Lupus erythematosus ("lupus vulgaris (A18.4)")

Back-references to A18

• Type 2 Excludes: A31 Infection due to other mycobacteria ("tuberculosis (A15-A19)")

Diagnosis Index entries for A18.4

• 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
• 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

Nearby codes

• A18.2 Tuberculous peripheral lymphadenopathy
• A18.3 Tuberculosis of intestines, peritoneum and mesenteric glands
• A18.31 Tuberculous peritonitis
• A18.32 Tuberculous enteritis
• A18.39 Retroperitoneal tuberculosis
• A18.4 Tuberculosis of skin and subcutaneous tissue (this code)
• A18.5 Tuberculosis of eye
• A18.50 Tuberculosis of eye, unspecified
• A18.51 Tuberculous episcleritis
• A18.52 Tuberculous keratitis
• A18.53 Tuberculous chorioretinitis