A18.4
Tuberculosis of skin and subcutaneous tissue
Billable FY2026 2025-10-01 → 2026-09-30
Exclusions 14 never code together
A18.4code
A15-A19block
Excludes1
- congenital tuberculosis (P37.0)P37.0
- nonspecific reaction to test for tuberculosis without active tuberculosis (R76.1-)R76.1-
- pneumoconiosis associated with tuberculosis, any type in A15 (J65)A15J65
- positive PPD (R76.11)R76.11
- positive tuberculin skin test without active tuberculosis (R76.11)R76.11
- sequelae of tuberculosis (B90.-)B90.-
- silicotuberculosis (J65)J65
A00-B99chapter
Excludes1
- certain localized infections - see body system-related chapters
Excludes2
- carrier or suspected carrier of infectious disease (Z22.-)Z22.-
- infectious and parasitic diseases complicating pregnancy, childbirth and the puerperium (O98.-)O98.-
- infectious and parasitic diseases specific to the perinatal period (P35-P39)P35-P39
- influenza and other acute respiratory infections (J00-J22)J00-J22
Excludes1 — never code together. The excluded condition and this one are mutually exclusive.
Excludes2 — not included here, but the patient may have both. Code both when documented.
Instructional notes 10
A18.4code
Inclusion terms
- Erythema induratum, tuberculous
- Lupus exedens
- Lupus vulgaris NOS
- Lupus vulgaris of eyelid
- Scrofuloderma
- Tuberculosis of external ear
Index entries leading here 19
- Tuberculosis, tubercular, tuberculous (calcification) (calcified) (caseous) (chromogenic acid-fast bacilli) (degeneration) (fibrocaseous) (fistula) (interstitial) (isolated circumscribed lesions) (necrosis) (parenchymatous) (ulcerative) A15.9
- abscess (respiratory) A15.9
- skin (primary) A18.4
- cellulitis (primary) A18.4
- colliquativa (primary) A18.4
- cutis (colliquativa) (primary) A18.4
- ear (inner) (middle) A18.6
- erythema (induratum) (nodosum) (primary) A18.4
- eyelid (primary) (lupus) A18.4
- indurativa (primary) A18.4
- lichenoides (primary) A18.4
- lupus vulgaris A18.4
- papulonecrotic (a) (primary) A18.4
- paronychia (primary) A18.4
- skin (any site) (primary) A18.4
- subcutaneous tissue (cellular) (primary) A18.4
- subcutis (primary) A18.4
- tarsitis A18.4
- ulcer (skin) (primary) A18.4
- verruca, verrucosa (cutis) (primary) A18.4
- abscess (respiratory) A15.9
- Acnitis (primary) A18.4
- Bazin's disease (primary) (tuberculous) A18.4
- Cellulitis (diffuse) (phlegmonous) (septic) (suppurative) L03.90
- tuberculous (primary) A18.4
- Ulcus — see also Ulcer
- cutis tuberculosum A18.4
- Erythema, erythematous (infectional) (inflammation) L53.9
- Lupus
- Gumma (syphilitic) A52.79
- Lichen L28.0
- scrofulosus (primary) (tuberculous) A18.4
- Lichenoides tuberculosis (primary) A18.4
- Verruca (due to HPV) (filiformis) (simplex) (viral) (vulgaris) B07.9
- Paronychia — see also Cellulitis, digit
- tuberculous (primary) A18.4
- Wart (due to HPV) (filiform) (infectious) (viral) B07.9
- Scrofulide (primary) (tuberculous) A18.4
- Scrofuloderma, scrofulodermia (any site) (primary) A18.4
- Scrofulosus lichen (primary) (tuberculous) A18.4
- Ulcer, ulcerated, ulcerating, ulceration, ulcerative
- Tarsitis (eyelid) H01.8
- tuberculous A18.4
- Tuberculid, tuberculide (indurating, subcutaneous) (lichenoid) (miliary) (papulonecrotic) (primary) (skin) A18.4
Alongside this code 8 same parent — A18
A18.0 Tuberculosis of bones and joints category A18.1 Tuberculosis of genitourinary system category A18.2 Tuberculous peripheral lymphadenopathy A18.3 Tuberculosis of intestines, peritoneum and mesenteric glands category A18.5 Tuberculosis of eye category A18.6 Tuberculosis of (inner) (middle) ear A18.7 Tuberculosis of adrenal glands A18.8 Tuberculosis of other specified organs category
Medications 2
MED-RT files conditions by MeSH, which carves the world differently from ICD-10. These are name matches on this code's description, offered as candidates — not as an assertion that they are this code.
Additional references
AHA Coding Clinic® Licence required
Official coding advice for this code. Published by the American Hospital Association. Not included in this installation.