T25.529A Corrosion of first degree of unspecified foot, initial encounter

ICD-10-CM T25.529A: Corrosion of first degree of unspecified foot, initial encounter

ICD-10-CM code T25.529A identifies a first-degree corrosion of an unspecified foot during an initial encounter. The code appears in official billing references and diagnostic code trees alongside related ankle and foot burn or corrosion classifications. The available source documents establish the code label and its placement within the ICD-10-CM hierarchy but do not provide specific clinical treatment guidelines or coverage determinations for this condition. 3 4

Plain-language overview

The ICD-10-CM code T25.529A is labeled as corrosion of first degree of unspecified foot, initial encounter, providing a standardized diagnostic designation for this specific clinical presentation. 3 4

What this code represents

The code T25.529A is listed within the T25 category, which encompasses burns and corrosions of the ankle and foot, and it specifically denotes a first-degree corrosion of an unspecified foot. 4

Coding details

The seventh character A in the code T25.529A denotes an initial encounter, distinguishing it from the subsequent encounter code T25.529D which shares the same first-degree unspecified foot corrosion description. 3 4

The code tree for ankle and foot corrosions includes distinct codes for right foot and left foot injuries, such as T25.521A and T25.522A, while T25.529A is utilized when the foot is unspecified. 4

Documentation considerations

The available source documents list the official code description and encounter character but do not explicitly establish the specific clinical documentation elements required to support the use of code T25.529A. 3 4

What the sources add

A Centers for Medicare and Medicaid Services billing and coding article includes T25.529A in a list of codes, while an ICD-10-CM code tree provides the hierarchical context of the code among other ankle and foot burn and corrosion classifications. 3 4

Clinical context

A clinical consensus document on burn wounds focuses on the treatment of second-degree burns and further dividing deep second-degree burn wounds, which is distinct from the first-degree corrosion represented by T25.529A. 2

Coverage and utilization context

The inclusion of T25.529A within a CMS billing and coding article establishes its presence in administrative billing references, but the cited excerpt does not explicitly state any payer-specific coverage determinations for this code. 3

Questions to verify

A retrospective analysis of burn injuries utilized diagnostic codes within a healthcare database to evaluate subjects, but the excerpt does not specify whether T25.529A was included in this research analysis. 1

Sources

1. Retrospective Analysis of Burn Injuries in Children with Autism Spectrum Disorder — pmc.ncbi.nlm.nih.gov; accessed 2026-07-25.
2. Consensus on the treatment of second-degree burn wounds (2024 edition) — pmc.ncbi.nlm.nih.gov; accessed 2026-07-25.
3. Article - Billing and Coding: Magnesium (A59186) — cms.gov; accessed 2026-07-25.
4. ICD-10-CM 2024 | T25 - Burn and corrosion of ankle and foot — unboundmedicine.com; accessed 2026-07-25.