ICD-10 Code G56.42 – Causalgia of left upper limb (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code G56.42 – Causalgia of left upper limb
What it is
This code identifies causalgia, a severe burning pain syndrome affecting the left upper limb, usually after nerve injury. It is used when the documentation specifically states causalgia in that limb.
Clinical signs
Typical findings include persistent burning pain, marked sensitivity to touch, and pain that seems out of proportion to the injury. Clinical features vary; refer to documentation.
When to use this code
Use G56.42 when the provider documents causalgia of the left arm, forearm, wrist, or hand, and the laterality is clear. You should code it when the record supports a localized neuropathic pain syndrome rather than a vague pain complaint. Check documentation if the note only mentions complex regional pain syndrome without specifying causalgia.
Do not use for
Do not use this code for generalized limb pain, unspecified neuropathy, or pain without a documented causalgia diagnosis. Do not assign it if the affected side is not confirmed.
Coding tip
Verify both laterality and the exact term “causalgia” in the assessment before assigning G56.42.