2027 ICD-10-CM Diagnosis Code A31.1Cutaneous mycobacterial infection
ICD-10-CM Codes›A00–B99›A30-A49›A31
- Billable — Valid for Submission
- CC — Complication or Comorbidity
- Not Chronic
A31.1 is a billable ICD-10-CM diagnosis code for cutaneous mycobacterial infection. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 606 through 607. As a secondary diagnosis, it counts as a complication or comorbidity (CC) and moves an inpatient stay to a higher severity level within its MS-DRG family. It does not count, however, when the principal diagnosis is one of 5 closely related codes. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Bacterial infections and Skin and subcutaneous tissue infections.
Code Identity
Code Classification
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- Buruli ulcer
- Cutaneous infectious disease caused by Mycobacteria
- Cutaneous mycobacterium marinum infection
- Dermatosis secondary to peripheral nerve disorder
- Fish tank granuloma
- Hyperimmune cutaneous reaction to atypical mycobacteria
- Hyperimmune cutaneous reaction to mycobacterium avium-intracellulare
- Infection caused by Mycobacterium chelonei
- Infection caused by Mycobacterium gordonae
- Infection caused by Mycobacterium haemophilum
- Infection caused by Mycobacterium malmoense
- Infection caused by Mycobacterium marinum
- Infection caused by Mycobacterium scrofulaceum
- Infection caused by Mycobacterium szulgai
- Infection caused by Mycobacteroides abscessus
- Infection of skin caused by Mycobacterium haemophilum
- Mycobacterium avium intracellulare infection of skin
- Mycobacterium fortuitum infection of skin
- Mycobacterium gordonae infection of skin
- Mycobacterium malmoense infection of skin
- Mycobacterium scrofulaceum infection of skin
- Mycobacterium szulgai infection of skin
- Mycobacteroides abscessus infection of skin
- Mycobacteroides chelonae infection of skin
- Neuropathic ulcer of skin caused by Mycobacterium leprae
- Non-pyogenic bacterial infection of skin
Instructional NotesGuidance
Instructions from the official ICD-10-CM Tabular List that apply to A31.1: its own notes plus those printed at A31 and Chapter 1. A note printed at a category, block or chapter applies to every code under it.
Includes
Further defines, or gives examples of, the content of the category.
- diseases generally recognized as communicable or transmissible
Applicable To
Conditions this code is used for: synonyms of the title or, for "other specified" codes, the conditions assigned to it. The list is not exhaustive.
- Buruli ulcer
- Infection due to Mycobacterium marinum
- Infection due to Mycobacterium ulcerans
Excludes2
Not included here: the excluded condition is not part of this code, but a patient may have both, so both codes may be reported.
- 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)
Use Additional Code
Add a second code, after this one, to fully describe the condition.
- code to identify resistance to antimicrobial drugs (Z16.-)
Source: CMS ICD-10-CM Tabular List. How to read instructional notes.
Index to Diseases and InjuriesGuidance
Alphabetical index entries that point to this code.
Buruli ulcer A31.1
Disease, diseased See Also: Syndrome;
swimming-pool granuloma A31.1
swimming pool A31.1
Infection, infected, infective (opportunistic) B99.9
swimming pool A31.1
swimming pool bacillus A31.1
Mycobacterium, mycobacterial (infection) A31.9
cutaneous A31.1
balnei A31.1
cutaneous A31.1
luciflavum A31.1
marinum (M. balnei) A31.1
ulcerans A31.1
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
Clinical InformationClinical
Buruli Ulcer
a lesion in the skin and subcutaneous tissues due to infections by mycobacterium ulcerans. it was first reported in uganda, africa.
Patient EducationClinical
Mycobacterial Infections
Mycobacteria are a type of germ. There are many different kinds. The most common one causes tuberculosis. Another one causes leprosy. Still others cause infections that are called atypical mycobacterial infections. They aren't "typical" because they don't cause tuberculosis.
Read the full article at MedlinePlus
Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.
Convert A31.1 to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About A31.1Overview
What is the ICD-10 code for cutaneous mycobacterial infection?
The ICD-10-CM code for cutaneous mycobacterial infection is A31.1 (sometimes written as A311). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
Is A31.1 (Infection due to other mycobacteria) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report cutaneous mycobacterial infection on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
What MS-DRG does A31.1 group to?
When cutaneous mycobacterial infection is the principal diagnosis on an inpatient stay, it groups to MS-DRG 607, 606, with relative weights from 0.8772 to 1.5721 depending on complications. Higher weights mean higher Medicare reimbursement.
Is A31.1 a CC or MCC?
CMS lists A31.1 as a CC (complication or comorbidity) for FY 2027. Reported as a secondary diagnosis, it moves the inpatient stay to a higher-weighted DRG within its severity family. It does not count when the principal diagnosis is one of the 5 closely related codes in its exclusion list.
What is the ICD-9 equivalent of A31.1?
Under the General Equivalence Mappings, cutaneous mycobacterial infection converts to ICD-9-CM 031.1 (cutaneous mycobacteria). The mapping is a direct match.
