Convert to ICD-10-CM: 
991.2 converts approximately to:
- 2015/16 ICD-10-CM T33.829A Superficial frostbite of unspecified foot, initial encounterOr: 
- 2015/16 ICD-10-CM T33.839A Superficial frostbite of unspecified toe(s), initial encounterOr: 
- 2015/16 ICD-10-CM T34.829A Frostbite with tissue necrosis of unspecified foot, initial encounter
 ICD-9-CM Volume 2 Index entries containing back-references to 
991.2:
- Frostbite 991.3  foot 991.2 foot 991.2