T24.639A Corrosion of second degree of unspecified lower leg, initial encounter

Billable ICD-10-CM code, FY2026.

Built from T24.639 with 7th character A (initial encounter).

Applies from T24 Burn and corrosion of lower limb, except ankle and foot

Excludes2 (not included here)

• burn and corrosion of ankle and foot (T25.-)
• burn and corrosion of hip region (T21.-)

7th character note

• The appropriate 7th character is to be added to each code from category T24

7th character required

• A — initial encounter
• D — subsequent encounter
• S — sequela

Applies from T24.6 Corrosion of second degree of lower limb, except ankle and foot

Code first

• (T51-T65) to identify chemical and intent

Use additional code

• external cause code to identify place (Y92)

Code annotations containing back-references to T24.639A

Back-references to T24

• Type 1 Excludes: T66 Radiation sickness, unspecified ("burns (T20-T31)")
• Type 2 Excludes: T67 Effects of heat and light ("burns (T20-T31)")
• Type 2 Excludes: T75 Other and unspecified effects of other external causes ("burns (electric) (T20-T31)")

Diagnosis Index entries for T24.639A

• Corrosion (injury) (acid) (caustic) (chemical) (lime) (external) (internal) › calf › second degree

Nearby codes

• T24.632 Corrosion of second degree of left lower leg
• T24.632A Corrosion of second degree of left lower leg, initial encounter
• T24.632D Corrosion of second degree of left lower leg, subsequent encounter
• T24.632S Corrosion of second degree of left lower leg, sequela
• T24.639 Corrosion of second degree of unspecified lower leg
• T24.639A Corrosion of second degree of unspecified lower leg, initial encounter (this code)
• T24.639D Corrosion of second degree of unspecified lower leg, subsequent encounter
• T24.639S Corrosion of second degree of unspecified lower leg, sequela
• T24.69 Corrosion of second degree of multiple sites of lower limb, except ankle and foot
• T24.691 Corrosion of second degree of multiple sites of right lower limb, except ankle and foot
• T24.691A Corrosion of second degree of multiple sites of right lower limb, except ankle and foot, initial encounter