2021 ICD-10-CM Diagnosis Code A18.4

Tuberculosis of skin and subcutaneous tissue

    2016 2017 2018 2019 2020 2021 Billable/Specific Code
  • A18.4 is a billable/specific ICD-10-CM code that can be used to indicate a diagnosis for reimbursement purposes.
  • The 2021 edition of ICD-10-CM A18.4 became effective on October 1, 2020.
  • This is the American ICD-10-CM version of A18.4 - other international versions of ICD-10 A18.4 may differ.
Applicable To
  • Erythema induratum, tuberculous
  • Lupus excedens
  • Lupus vulgaris NOS
  • Lupus vulgaris of eyelid
  • Scrofuloderma
  • Tuberculosis of external ear
Type 2 Excludes
Type 2 Excludes Help
A type 2 excludes note represents "not included here". A type 2 excludes note indicates that the condition excluded is not part of the condition it is excluded from but a patient may have both conditions at the same time. When a type 2 excludes note appears under a code it is acceptable to use both the code (A18.4) and the excluded code together.
  • lupus erythematosus (
    ICD-10-CM Diagnosis Code L93
    • L93 Lupus erythematosus
      • L93.0 Discoid lupus erythematosus
      • L93.1 Subacute cutaneous lupus erythematosus
      • L93.2 Other local lupus erythematosus
    L93.-
    )
  • systemic lupus erythematosus (
    ICD-10-CM Diagnosis Code M32
    • M32 Systemic lupus erythematosus (SLE)
      • M32.0 Drug-induced systemic lupus erythematosus
      • M32.1 Systemic lupus erythematosus with organ or sy...
        • M32.10 Systemic lupus erythematosus, organ or system...
        • M32.11 Endocarditis in systemic lupus erythematosus
        • M32.12 Pericarditis in systemic lupus erythematosus
        • M32.13 Lung involvement in systemic lupus erythemato...
        • M32.14 Glomerular disease in systemic lupus erythema...
        • M32.15 Tubulo-interstitial nephropathy in systemic l...
        • M32.19 Other organ or system involvement in systemic...
      • M32.8 Other forms of systemic lupus erythematosus
      • M32.9 Systemic lupus erythematosus, unspecified
    M32.-
    )
The following code(s) above A18.4 contain annotation back-references
Annotation Back-References
In this context, annotation back-references refer to codes that contain:
  • Applicable To annotations, or
  • Code Also annotations, or
  • Code First annotations, or
  • Excludes1 annotations, or
  • Excludes2 annotations, or
  • Includes annotations, or
  • Note annotations, or
  • Use Additional annotations
that may be applicable to A18.4:
  • A00-B99
    2021 ICD-10-CM Range A00-B99

    Certain infectious and parasitic diseases

    Includes
    • diseases generally recognized as communicable or transmissible
    Type 1 Excludes
    • certain localized infections - see body system-related chapters
    Type 2 Excludes
    • 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 to identify resistance to antimicrobial drugs (Z16.-)
    Certain infectious and parasitic diseases
  • A15-A19
    2021 ICD-10-CM Range A15-A19

    Tuberculosis

    Includes
    • infections due to Mycobacterium tuberculosis and Mycobacterium bovis
    Type 1 Excludes
    • 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)
    Tuberculosis
Approximate Synonyms
  • Tuberculosis (tb) of subcutaneous tissue
  • Tuberculosis (tb) verrucosa cutis
  • Tuberculosis (tb) with erythema nodosum
  • Tuberculosis of subcutaneous cellular tissue
  • Tuberculosis verrucosa cutis
  • Tuberculous erythema nodosum
Clinical Information
  • A form of cutaneous tuberculosis. It is seen predominantly in women and typically involves the nasal mucosa; buccal mucosa; and conjunctival mucosa.
  • A type of panniculitis characterized histologically by the presence of granulomas, vasculitis, and necrosis. It is traditionally considered to be the tuberculous counterpart of nodular vasculitis, but is now known to occur without tuberculous precedent. It is seen most commonly in adolescent and menopausal women, is initiated or exacerbated by cold weather, and typically presents as one or more recurrent erythrocyanotic nodules or plaques on the calves. The nodules may progress to form indurations, ulcerations, and scars.
ICD-10-CM A18.4 is grouped within Diagnostic Related Group(s) (MS-DRG v38.0):
  • 606 Minor skin disorders with mcc
  • 607 Minor skin disorders without mcc
  • 974 Hiv with major related condition with mcc
  • 975 Hiv with major related condition with cc
  • 976 Hiv with major related condition without cc/mcc

Convert A18.4 to ICD-9-CM

Code History
  • 2016 (effective 10/1/2015): New code (first year of non-draft ICD-10-CM)
  • 2017 (effective 10/1/2016): No change
  • 2018 (effective 10/1/2017): No change
  • 2019 (effective 10/1/2018): No change
  • 2020 (effective 10/1/2019): No change
  • 2021 (effective 10/1/2020): No change
Code annotations containing back-references to A18.4:
  • Type 1 Excludes: L52
    , L93
    , L93
    ICD-10-CM Diagnosis Code L52

    Erythema nodosum

      2016 2017 2018 2019 2020 2021 Billable/Specific Code
    Type 1 Excludes
    • tuberculous erythema nodosum (A18.4)
    ICD-10-CM Diagnosis Code L93

    Lupus erythematosus

      2016 2017 2018 2019 2020 2021 Non-Billable/Non-Specific Code
    Type 1 Excludes
    Use Additional
    • code for adverse effect, if applicable, to identify drug (T36-T50 with fifth or sixth character 5)
    ICD-10-CM Diagnosis Code L93

    Lupus erythematosus

      2016 2017 2018 2019 2020 2021 Non-Billable/Non-Specific Code
    Type 1 Excludes
    Use Additional
    • code for adverse effect, if applicable, to identify drug (T36-T50 with fifth or sixth character 5)
  • Type 2 Excludes: A18.5
    , A18.6
    ICD-10-CM Diagnosis Code A18.5

    Tuberculosis of eye

      2016 2017 2018 2019 2020 2021 Non-Billable/Non-Specific Code
    Type 2 Excludes
    • lupus vulgaris of eyelid (A18.4)
    ICD-10-CM Diagnosis Code A18.6

    Tuberculosis of (inner) (middle) ear

      2016 2017 2018 2019 2020 2021 Billable/Specific Code
    Applicable To
    • Tuberculous otitis media
    Type 2 Excludes
    • tuberculosis of external ear (A18.4)
    • tuberculous mastoiditis (A18.03)

Diagnosis Index entries containing back-references to A18.4:
  • Acnitis A18.4 (primary)
  • Bazin's disease A18.4 (primary) (tuberculous)
  • Cellulitis (diffuse) (phlegmonous) (septic) (suppurative) L03.90
    ICD-10-CM Diagnosis Code L03.90

    Cellulitis, unspecified

      2016 2017 2018 2019 2020 2021 Billable/Specific Code
    • tuberculous A18.4 (primary)
  • Erythema, erythematous (infectional) (inflammation) L53.9
    ICD-10-CM Diagnosis Code L53.9

    Erythematous condition, unspecified

      2016 2017 2018 2019 2020 2021 Billable/Specific Code
    Applicable To
    • Erythema NOS
    • Erythroderma NOS
    • induratum (nontuberculous) L52
      ICD-10-CM Diagnosis Code L52

      Erythema nodosum

        2016 2017 2018 2019 2020 2021 Billable/Specific Code
      Type 1 Excludes
      • tuberculous erythema nodosum (A18.4)
      • tuberculous A18.4
    • nodosum L52
      ICD-10-CM Diagnosis Code L52

      Erythema nodosum

        2016 2017 2018 2019 2020 2021 Billable/Specific Code
      Type 1 Excludes
      • tuberculous erythema nodosum (A18.4)
      • tuberculous A18.4
    • tuberculous A18.4 (primary)
  • Gumma (syphilitic) A52.79
    ICD-10-CM Diagnosis Code A52.79

    Other symptomatic late syphilis

      2016 2017 2018 2019 2020 2021 Billable/Specific Code
    Applicable To
    • Late syphilitic leukoderma
    • Syphilis of adrenal gland
    • Syphilis of pituitary gland
    • Syphilis of thyroid gland
    • Syphilitic splenomegaly
    Type 1 Excludes
    • syphilitic leukoderma (secondary) (A51.39)
    • scrofulous A18.4 (tuberculous)
    • tuberculous A18.4
  • Lichen L28.0
    ICD-10-CM Diagnosis Code L28.0

    Lichen simplex chronicus

      2016 2017 2018 2019 2020 2021 Billable/Specific Code
    Applicable To
    • Circumscribed neurodermatitis
    • Lichen NOS
    • scrofulosus A18.4 (primary) (tuberculous)
  • Lichenoides tuberculosis A18.4 (primary)
  • Lupus
  • Paronychia - see also Cellulitis, digit
    • tuberculous A18.4 (primary)
  • Scrofulide A18.4 (primary) (tuberculous)
  • Scrofuloderma, scrofulodermia A18.4 (any site) (primary)
  • Scrofulosus lichen A18.4 (primary) (tuberculous)
  • Tarsitis (eyelid) H01.8
    ICD-10-CM Diagnosis Code H01.8

    Other specified inflammations of eyelid

      2016 2017 2018 2019 2020 2021 Billable/Specific Code
    • tuberculous A18.4
  • Tuberculid, tuberculide A18.4 (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) A15.9
    ICD-10-CM Diagnosis Code A15.9

    Respiratory tuberculosis unspecified

      2016 2017 2018 2019 2020 2021 Billable/Specific Code
    • abscess (respiratory) A15.9
      ICD-10-CM Diagnosis Code A15.9

      Respiratory tuberculosis unspecified

        2016 2017 2018 2019 2020 2021 Billable/Specific Code
      • skin A18.4 (primary)
    • ear (inner) (middle) A18.6
      ICD-10-CM Diagnosis Code A18.6

      Tuberculosis of (inner) (middle) ear

        2016 2017 2018 2019 2020 2021 Billable/Specific Code
      Applicable To
      • Tuberculous otitis media
      Type 2 Excludes
      • tuberculosis of external ear (A18.4)
      • tuberculous mastoiditis (A18.03)
      • external A18.4 (primary)
      • skin A18.4 (primary)
    • ulcer (skin) (primary) A18.4
    • cellulitis A18.4 (primary)
    • colliquativa A18.4 (primary)
    • cutis A18.4 (colliquativa) (primary)
    • erythema A18.4 (induratum) (nodosum) (primary)
    • eyelid A18.4 (primary) (lupus)
    • indurativa A18.4 (primary)
    • lichenoides A18.4 (primary)
    • lupus vulgaris A18.4
    • papulonecrotic A18.4 (a) (primary)
    • paronychia A18.4 (primary)
    • skin A18.4 (any site) (primary)
    • subcutaneous tissue A18.4 (cellular) (primary)
    • subcutis A18.4 (primary)
    • tarsitis A18.4
    • verruca, verrucosa A18.4 (cutis) (primary)
  • Ulcer, ulcerated, ulcerating, ulceration, ulcerative
    • skin (atrophic) (chronic) (neurogenic) (non-healing) (perforating) (pyogenic) (trophic) (tropical) L98.499
      ICD-10-CM Diagnosis Code L98.499

      Non-pressure chronic ulcer of skin of other sites with unspecified severity

        2016 2017 2018 2019 2020 2021 Billable/Specific Code
      • tuberculous A18.4 (primary)
  • Ulcus - see also Ulcer
    • cutis tuberculosum A18.4
  • Verruca (due to HPV) (filiformis) (simplex) (viral) (vulgaris) B07.9
    ICD-10-CM Diagnosis Code B07.9

    Viral wart, unspecified

      2016 2017 2018 2019 2020 2021 Billable/Specific Code
    • necrogenica A18.4 (primary) (tuberculosa)
    • tuberculosa A18.4 (primary)
  • Wart (due to HPV) (filiform) (infectious) (viral) B07.9
    ICD-10-CM Diagnosis Code B07.9

    Viral wart, unspecified

      2016 2017 2018 2019 2020 2021 Billable/Specific Code
    • prosector A18.4 (tuberculous)
    • tuberculous A18.4

ICD-10-CM Codes Adjacent To A18.4
A18.14 Tuberculosis of prostate
A18.15 Tuberculosis of other male genital organs
A18.16 Tuberculosis of cervix
A18.17 Tuberculous female pelvic inflammatory disease
A18.18 Tuberculosis of other female genital organs
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
A18.5 Tuberculosis of eye
A18.50 …… unspecified
A18.51 Tuberculous episcleritis
A18.52 Tuberculous keratitis
A18.53 Tuberculous chorioretinitis
A18.54 Tuberculous iridocyclitis
A18.59 Other tuberculosis of eye
A18.6 Tuberculosis of (inner) (middle) ear
A18.7 Tuberculosis of adrenal glands
A18.8 Tuberculosis of other specified organs

Reimbursement claims with a date of service on or after October 1, 2015 require the use of ICD-10-CM codes.