ICD-10-CM > S00-T88 > T20-T25 > T25 > T25.5 > T25.53 > T25.539 T25.539 Corrosion of first degree of unspecified toe(s) (nail) Non-Billable/Non-Specific Codes T25.539A..., initial encounterT25.539D..., subsequent encounterT25.539S..., sequela