2027 ICD-10-CM Diagnosis Code M35.4Diffuse (eosinophilic) fasciitis
ICD-10-CM Codes›M00–M99›M30-M36›M35
- Billable — Valid for Submission
- Not Chronic
M35.4 is a billable ICD-10-CM diagnosis code for diffuse (eosinophilic) fasciitis. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 557 through 558. Coders also document this condition as eosinophilic fasciitis caused by L-tryptophan. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Systemic lupus erythematosus and connective tissue disorders.
Code Identity
Code Classification
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- Eosinophilic fasciitis caused by L-tryptophan
- Fasciitis with eosinophilia syndrome
Instructional NotesGuidance
Instructions from the official ICD-10-CM Tabular List that apply to M35.4: its own notes plus those printed at M35, block M30-M36, and Chapter 13. 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.
- autoimmune disease NOS
- collagen (vascular) disease NOS
- systemic autoimmune disease
- systemic collagen (vascular) disease
Excludes1
Not coded here: the excluded code is never reported together with this one, unless the two conditions are unrelated.
- reactive perforating collagenosis (L87.1)
- autoimmune disease, single organ or single cell-type -code to relevant condition category
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.
- arthropathic psoriasis (L40.5-)
- certain conditions originating in the perinatal period (P04-P96)
- certain infectious and parasitic diseases (A00-B99)
- compartment syndrome (traumatic) (T79.A-)
- complications of pregnancy, childbirth and the puerperium (O00-O9A)
- congenital malformations, deformations, and chromosomal abnormalities (Q00-Q99)
- endocrine, nutritional and metabolic diseases (E00-E88)
- injury, poisoning and certain other consequences of external causes (S00-T88)
- neoplasms (C00-D49)
- symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)
Notes
General instructions on how these codes are used.
- Use an external cause code following the code for the musculoskeletal condition, if applicable, to identify the cause of the musculoskeletal condition
Source: CMS ICD-10-CM Tabular List. How to read instructional notes.
Referenced in Other NotesGuidance
Instructional notes printed at other codes that name M35.4, its category, or a range that includes it.
Excludes1 3
These codes carry an Excludes1 note naming M35.4: they are not reported together with it, unless the two conditions are unrelated.
Excludes2 4
These codes carry an Excludes2 note naming M35.4: its condition is not part of those codes, and both may be reported when the patient has both.
- Chapter 9 (I00-I99) Diseases of the circulatory system
- I77 Other disorders of arteries and arterioles
- J82 Pulmonary eosinophilia, not elsewhere classified
- Chapter 12 (L00-L99) Diseases of the skin and subcutaneous tissue
Code First 1
These codes say to code first a condition named in the note, and M35.4 is one of the conditions named.
- J84.170 Interstitial lung disease with progressive fibrotic phenotype in diseases classified elsewhere
Index to Diseases and InjuriesGuidance
Alphabetical index entries that point to this code.
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
Patient EducationClinical
Connective Tissue Disorders
Your connective tissue supports many different parts of your body, such as your skin, eyes, and heart. It is like a "cellular glue" that gives your body parts their shape and helps keep them strong. It also helps some of your tissues do their work. It is made of many kinds of proteins. Cartilage and fat are types of connective tissue.
Read the full article at MedlinePlus
Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.
Convert M35.4 to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About M35.4Overview
What is the ICD-10 code for diffuse (eosinophilic) fasciitis?
The ICD-10-CM code for diffuse (eosinophilic) fasciitis is M35.4 (sometimes written as M354). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
Is M35.4 (Other systemic involvement of connective tissue) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report diffuse (eosinophilic) fasciitis on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
What MS-DRG does M35.4 group to?
When diffuse (eosinophilic) fasciitis is the principal diagnosis on an inpatient stay, it groups to MS-DRG 557, 558, with relative weights from 0.8873 to 1.4883 depending on complications. Higher weights mean higher Medicare reimbursement.
Can M35.4 be reported with L87.1?
Not as a rule. The Excludes1 note at M35, which applies to M35.4, lists "reactive perforating collagenosis (L87.1)". An Excludes1 note means the excluded code is never reported together with this one; the only exception is when the two conditions are unrelated to each other (Official Guidelines, Section I.A.12.a).
What is the ICD-9 equivalent of M35.4?
Under the General Equivalence Mappings, diffuse (eosinophilic) fasciitis converts to ICD-9-CM 728.89 (muscle/ligament dis NEC). The mapping is approximate, so confirm the match fits the documentation.
