2026 ICD-10-CM Diagnosis Code G56.42Causalgia of left upper limb

ICD-10-CM Codes›G00–G99›G50-G59›G56

ICD-10-CM G56.42
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

G56.42 is a billable ICD-10-CM diagnosis code for causalgia of left upper limb. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026). Coders also document this condition as chronic pain of left upper limb. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Nerve and nerve root disorders.

Code Identity

ICD-10-CM Code
G56.42
Billable Status
Yes — Valid for Submission
Code Describes
Causalgia of left upper limb
Short Description
Causalgia of left upper limb
Same as the full description in the CMS dataset.
Parent Code
G56.4
Causalgia of upper limb

Code Classification

ChapterG00–G99Diseases of the nervous system
SectionG50-G59Nerve, nerve root and plexus disorders
CategoryG56Mononeuropathies of upper limb
This CodeG56.42Causalgia of left upper limb

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Chronic pain of left upper limb
  • Complex regional pain syndrome of upper limb
  • Complex regional pain syndrome type II of left upper limb
  • Complex regional pain syndrome, type II
  • Complex regional pain syndrome, type II, upper limb
  • Neuralgia of left upper limb

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR NVS017
Nerve and nerve root disorders
Default principal diagnosis: inpatient Yes · outpatient Yes

Patient EducationClinical

Complex Regional Pain Syndrome

Complex regional pain syndrome (CRPS) is a chronic pain condition. It causes intense pain, usually in the arms, hands, legs, or feet. It may happen after an injury, either to a nerve or to tissue in the affected area. Rest and time may only make it worse.

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Convert G56.42 to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM
354.4 Causalgia upper limb
Approximate The match is approximate rather than exact.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About G56.42Overview

Is G56.42 (Causalgia of upper limb) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report causalgia of left upper limb on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What is the ICD-9 equivalent of G56.42?

Under the General Equivalence Mappings, causalgia of left upper limb converts to ICD-9-CM 354.4 (causalgia upper limb). The mapping is approximate, so confirm the match fits the documentation.

Footnotes

[1] Chronic - a chronic condition code indicates a condition lasting 12 months or longer and its effect on the patient based on one or both of the following criteria:

  • The condition results in the need for ongoing intervention with medical products,treatment, services, and special equipment
  • The condition places limitations on self-care, independent living, and social interactions.