ICD-10 Code for Blister on Buttock
The ICD-10 code for a non-thermal blister on the buttock is S30.820 (blister of buttock, unspecified side) or S30.821/S30.822 for left or right buttock specifically.
Primary Coding Structure
The appropriate code depends on the specific characteristics and etiology of the blister:
Non-Thermal Blisters (Most Common)
- S30.820 - Blister (nonthermal) of buttock, unspecified 1
- S30.821 - Blister (nonthermal) of left buttock 1
- S30.822 - Blister (nonthermal) of right buttock 1
These codes capture friction blisters, pressure blisters, or other non-burn related blistering on the buttock region 2.
Thermal (Burn) Blisters
If the blister resulted from a burn injury, use codes from the T20-T32 series instead:
- T21.x series for burns of the trunk, which includes the buttock region 3
- The specific code requires additional characters to specify degree of burn and laterality 2
Important Coding Considerations
Laterality Specification
ICD-10 provides significantly improved specificity over ICD-9 by requiring laterality (left vs. right) designation 1, 2. This enhanced granularity allows for better tracking of wound location and progression during episodes of care 2.
Seventh Character Requirement
Most injury codes in ICD-10 require a seventh character to indicate the encounter type 1:
- A - Initial encounter
- D - Subsequent encounter
- S - Sequela
For example: S30.821A would indicate an initial encounter for a blister on the left buttock 1.
Documentation Requirements for Accurate Coding
To ensure proper code assignment, clinical documentation should include 4:
- Specific anatomic location using the terms "buttock," "left buttock," or "right buttock" 4
- Size in centimeters of the blister 4
- Blister characteristics: tense versus flaccid, intact versus ruptured 4
- Underlying skin appearance: erythematous, normal, or other 4
- Etiology: friction, pressure, thermal, or other cause 3
Common Coding Pitfalls
Avoid Misclassification of Etiology
Do not use S30.82x codes for burn blisters, as these require T-codes from the burn section 3. The distinction between thermal and non-thermal blisters is critical for accurate coding 2.
Ensure Complete Code Structure
ICD-10 codes must include all required characters, including the seventh character for encounter type 1. Incomplete codes will be rejected by billing systems and compromise data quality 5.
Document Laterality When Possible
While S30.820 (unspecified side) exists, using laterality-specific codes (S30.821 or S30.822) provides superior data for tracking and quality improvement 2. The increased specificity of ICD-10 improves identification and monitoring of conditions during care episodes 2.