ICD-10-CM > S00-T88 > T20-T25 > T23 > T23.4 > T23.44 > T23.449 T23.449 Corrosion of unspecified degree of unspecified multiple fingers (nail), including thumb Non-Billable/Non-Specific Codes T23.449A..., initial encounterT23.449D..., subsequent encounterT23.449S..., sequela