ICD-10-CM > S00-T88 > T20-T25 > T23 > T23.5 > T23.51 > T23.511 T23.511 Corrosion of first degree of right thumb (nail) Non-Billable/Non-Specific Codes T23.511A..., initial encounterT23.511D..., subsequent encounterT23.511S..., sequela