M30.1

Systemic necrotizing vasculitis with granuloma formation and obligate pulmonary involvement, corresponding to eosinophilic granulomatosis with polyangiitis (EGPA), formerly called Churg-Strauss syndrome.

Verified May 8, 2026 · 5 sources ↓

Status: Billable
Chapter: 13
Related CPT: 5
Region: Multi-region

Drawn from CDCICD10DataUnboundmedicineCMSCdek

Documentation tips

What should appear in the chart to support M30.1.

Source · Editorial brief grounded in 5 cited references ↓

Provider must explicitly document EGPA, Churg-Strauss syndrome, or allergic granulomatous angiitis — a generic 'vasculitis' note is insufficient to support M30.1.
Record eosinophil count or percentage in the note; peripheral eosinophilia is a diagnostic hallmark and supports medical necessity for specialist workup.
Document all active organ-system manifestations separately (pulmonary, renal, cardiac, neurologic, cutaneous) so secondary codes can be assigned accurately.
Note whether asthma preceded systemic vasculitis — this clinical timeline is characteristic of EGPA and strengthens audit defense for the code.
If biopsy was performed, capture the pathology result (necrotizing vasculitis with eosinophilic granulomas) in the assessment; histologic confirmation is the strongest documentation anchor.
Record the treating or diagnosing specialist (rheumatology, pulmonology) who confirmed the diagnosis, especially in shared-care settings where coding responsibility may be questioned.

Related CPT procedures

Procedure codes commonly billed with M30.1. Linking the right diagnosis to the right procedure is what establishes medical necessity.

Source · CMS LCDs · AAOS specialty guidance · claims-pattern analysis

99213 $95.19

Established patient office or outpatient visit requiring 20–29 minutes of total time or low-complexity medical decision-making.

99214 $135.61

Office visit for an established patient requiring moderate-complexity medical decision making (MDM), or 30–39 minutes of total provider time on the date of service.

99215 $192.39

Highest-level office or outpatient E/M visit for an established patient, qualifying via high-complexity medical decision making or 40–54 minutes of total provider time on the date of service.

86235 View procedure details

85025 View procedure details

Common coding pitfalls

The recurring mistakes coders make with M30.1 and adjacent codes.

Source · Editorial brief grounded in CDC ICD-10-CM tabular guidance, AAOS coding references, and cited references ↓

Coding M30.0 (polyarteritis nodosa) instead of M30.1 when the chart documents lung involvement or eosinophilia — these features move the diagnosis to M30.1.
Assigning only M30.1 and omitting secondary codes for documented complications such as pulmonary hypertension (I27.0) or interstitial lung disease (J84.9), which leads to undercoded claim complexity.
Using an unspecified vasculitis code (e.g., M31.9) when the provider has clearly documented EGPA or Churg-Strauss — M30.1 is the specific, billable code and should always be used when the diagnosis is confirmed.
Appending a 7th-character extension to M30.1 — this is an M-code with no 7th-character structure; any such addition will trigger a claim rejection.
Failing to query the provider when the note mentions 'Churg-Strauss' historically but current documentation only describes eosinophilic asthma — M30.1 requires active systemic vasculitis, not just a history of the prodromal phase.

Clinical context

Source · Editorial summary grounded in 5 cited references ↓

M30.1 is the single billable code for eosinophilic granulomatosis with polyangiitis (EGPA) — the condition historically known as Churg-Strauss syndrome and also indexed as allergic granulomatous angiitis. It sits under parent code M30 (Polyarteritis nodosa and related conditions) within the M30–M36 systemic connective tissue disorders block. Use it when the provider has documented EGPA or Churg-Strauss, which is characterized by necrotizing angiitis, tissue granulomas, peripheral eosinophilia, and pulmonary involvement (asthma or eosinophilic infiltrates are frequently the presenting feature). Do not use M30.0 (polyarteritis nodosa) — eosinophilia and lung involvement are the clinical features that distinguish EGPA from classic polyarteritis nodosa, and the tabular list keeps them in separate codes.

Because EGPA is a multi-system disease, secondary codes for active manifestations are appropriate. Pulmonary hypertension secondary to connective tissue disease (I27.0) and interstitial lung disease (J84.9) are common companion codes when those complications are documented. Peripheral neuropathy, renal involvement, cardiac involvement, and skin lesions each have their own codes and should be added when clinically documented and confirmed by the treating provider. Follow the Alphabetic Index and official guideline Section I.C.15 for syndromic diagnoses: assign M30.1 as the primary code and add codes for manifestations that are not integral to the syndrome itself.

M30.1 carries no laterality modifier and no 7th-character extension — it is a fully specified 4-character code. No further specificity subdivisions exist within the ICD-10-CM tabular for this condition. The code has been valid and billable through every edition from FY2016 through FY2026.

Inclusion & exclusion notes

Per the official ICD-10-CM Tabular List.

Source · CDC ICD-10-CM Official Tabular List · 2026

Includes

Allergic granulomatous angiitis
Eosinophilic granulomatosis with polyangiitis [EGPA]

Sibling codes

Other billable codes under M30 (laterality / anatomic variants).

M30.0

Polyarteritis nodosa

M30.3

Mucocutaneous lymph node syndrome [Kawasaki]

M30.2

Juvenile polyarteritis

M30.8

Other conditions related to polyarteritis nodosa

Frequently asked questions

Source · Generated from the editorial pipeline, verified against 5 cited references ↓

01Is M30.1 the correct code for both 'Churg-Strauss syndrome' and 'EGPA'?

Yes. The ICD-10-CM tabular lists both 'Eosinophilic granulomatosis with polyangiitis [EGPA]' and 'Allergic granulomatous angiitis' as Applicable To terms under M30.1. Churg-Strauss is the legacy eponym; EGPA is the current preferred terminology. All three terms map to M30.1.

02Can M30.1 be used if the patient has a history of EGPA but is currently in remission?

Assign M30.1 for active disease. If the condition is in full remission and the encounter is for surveillance, use a personal history code (Z87.39, personal history of other musculoskeletal disorders) alongside the appropriate follow-up code. Query the provider if remission status is unclear.

03Should I add a separate asthma code when coding M30.1?

Asthma that is an integral feature of the EGPA disease process is generally not coded separately unless the provider documents it as a co-existing condition requiring independent management. Follow the ICD-10-CM guideline on syndromes (Section I.C.15) and the provider's clinical judgment about whether the asthma is integral or a separate condition.

04What is the ICD-9-CM crosswalk for M30.1?

M30.1 crosswalks from ICD-9-CM code 446.4 (Wegener's granulomatosis) in some legacy maps, but the more precise ICD-9 ancestor is 446.20 (hypersensitivity angiitis, unspecified). Verify with your payer's crosswalk tool before using legacy data for trending purposes.

05Does M30.1 require a 7th character?

No. M30.1 is a complete 4-character code. Adding any character beyond position 4 is invalid and will cause a claim rejection. The 7th-character extension convention applies to injury S-codes, not to M-codes in this block.

06What MS-DRG does M30.1 group to?

Under MS-DRG v43.0, M30.1 groups with other connective tissue disorder DRGs. The exact DRG assignment depends on the presence of comorbidities and complications (CC/MCC designation of secondary diagnoses), so complete complication coding directly affects reimbursement weight.

07Is M30.1 used in orthopedic practice, or is it primarily rheumatology or pulmonology?

EGPA is primarily a rheumatology and pulmonology diagnosis, but orthopedic practices may encounter it as a comorbidity when managing musculoskeletal manifestations (myalgia, arthralgia, mononeuritis multiplex). Code it as a secondary diagnosis in those encounters when the provider documents it in the assessment.

Sources & references

Editorial content was developed using the following public sources. Last verified May 8, 2026.

Mira AI Scribe

Mira's AI scribe captures the provider's stated diagnosis (EGPA, Churg-Strauss, or allergic granulomatous angiitis), documented eosinophil count, pulmonary findings, and any organ-system complications confirmed in the assessment. That structured capture prevents a downcode to unspecified vasculitis, ensures secondary complication codes are populated, and gives auditors the clinical narrative that justifies M30.1 over M30.0.

See how Mira captures M30.1 documentation