ICD-10-CM > S00-T88 > T20-T25 > T25 > T25.6 > T25.69 > T25.699 T25.699 Corrosion of second degree of unspecified ankle and foot Non-Billable/Non-Specific Codes T25.699A..., initial encounterT25.699D..., subsequent encounterT25.699S..., sequela