ICD-10 code for fever blister

The ICD-10-CM code for fever blister is B00.1 (Herpesviral vesicular dermatitis).

Within B00 (herpesviral [herpes simplex] infections), B00.1 is specifically for herpesviral vesicular dermatitis. Related codes cover eczema herpeticum (B00.0), herpesviral gingivostomatitis and pharyngotonsillitis (B00.2), herpesviral meningitis (B00.3), herpesviral encephalitis (B00.4), herpesviral ocular disease (B00.5), disseminated herpesviral disease (B00.7), other forms of herpesviral infections (B00.8) and herpesviral infection, unspecified (B00.9).

It is not a CC or MCC, so as a secondary diagnosis it doesn't change the MS-DRG severity level.

In MS-DRG v44.0, it is part of the grouping logic for DRG 154 (Other Ear, Nose, Mouth and Throat Diagnoses with MCC, relative weight 1.5921), DRG 155 (Other Ear, Nose, Mouth and Throat Diagnoses with CC, relative weight 0.9322), DRG 156 (Other Ear, Nose, Mouth and Throat Diagnoses without CC/MCC, relative weight 0.6659), DRG 791 (Prematurity with Major Problems, relative weight 4.1075), DRG 793 (Full Term Neonate with Major Problems, relative weight 4.2195), DRG 974 (HIV with Major Related Condition with MCC, relative weight 3.0506) and 2 more, in MDC 03 (Diseases and Disorders of the Ear, Nose, Mouth and Throat), MDC 15 (Newborns and Other Neonates with Conditions Originating in the Perinatal Period) and MDC 25 (Human Immunodeficiency Virus Infections), as a principal or secondary diagnosis. The DRG a claim lands in depends on the principal diagnosis, procedures and any CC/MCC secondary diagnoses.