ICD-10-CM > S00-T88 > T20-T25 > T24 > T24.5 > T24.53 > T24.539 T24.539 Corrosion of first degree of unspecified lower leg Non-Billable/Non-Specific Codes T24.539A..., initial encounterT24.539D..., subsequent encounterT24.539S..., sequela