ICD-10-CM > S00-T88 > S90-S99 > S90 > S90.5 > S90.52 > S90.521 S90.521 Blister (nonthermal), right ankle Non-Billable/Non-Specific Codes S90.521A..., initial encounterS90.521D..., subsequent encounterS90.521S..., sequela