ICD-10-CM > S00-T88 > T20-T25 > T25 > T25.4 > T25.49 > T25.499 T25.499 Corrosion of unspecified degree of multiple sites of unspecified ankle and foot Non-Billable/Non-Specific Codes T25.499A..., initial encounterT25.499D..., subsequent encounterT25.499S..., sequela