A31.1Cutaneous mycobacterial infection

A31.1 is the ICD-10-CM diagnosis code for cutaneous mycobacterial infection. It belongs to category A31 (infection due to other mycobacteria), block A30-A49 (other bacterial diseases) and chapter 1 (certain infectious and parasitic diseases). It is billable, so it can be reported on its own for dates of service from October 1, 2026 through September 30, 2027.

Within A31 (infection due to other mycobacteria), A31.1 is specifically for cutaneous mycobacterial infection. Related codes cover pulmonary mycobacterial infection (A31.0), disseminated mycobacterium avium-intracellulare complex (DMAC) (A31.2), other mycobacterial infections (A31.8) and mycobacterial infection, unspecified (A31.9).

As a secondary diagnosis it is a CC (complication or comorbidity), which can move an inpatient stay into the "with CC" MS-DRG of its family, unless the principal diagnosis excludes it.

In MS-DRG v44.0, it is part of the grouping logic for DRG 606 (Minor Skin Disorders with MCC, relative weight 1.5728) and DRG 607 (Minor Skin Disorders without MCC, relative weight 0.8772), in MDC 09 (Diseases and Disorders of the Skin, Subcutaneous Tissue and Breast), as a principal or secondary diagnosis. The DRG a claim lands in depends on the principal diagnosis, procedures and any CC/MCC secondary diagnoses.

It has been part of ICD-10-CM since the code set took effect on October 1, 2015 and hasn't changed since.

Before ICD-10, this condition was coded in ICD-9-CM as 031.1 (cutaneous diseases due to other mycobacteria).