ICD-10-CM > S00-T88 > T20-T25 > T23 > T23.6 > T23.64 > T23.642 T23.642 Corrosion of second degree of multiple left fingers (nail), including thumb Non-Billable/Non-Specific Codes T23.642A..., initial encounterT23.642D..., subsequent encounterT23.642S..., sequela