ICD-11 now “indexes” parental alienation as a disease. That means that if you go to the current draft of ICD-11 and search for “parental alienation”, it recognizes you and places you on the medical condition with the name that ICD-11 prefers, namely QE52.0 Caregiver-child relationship problem  which reads “Substantial and sustained dissatisfaction within a caregiver-child relationship associated with significant disturbance in functioning.”

This is huge, because it officially acknowledges parental alienation!!!!! It refers people to the terminology preferred by ICD-11. That’s fine.
ICD-10 is the current version.

In the words of one expert “ICD-11 has not formally been approved yet, but is clearly expected to be approved at the WHO general assembly in may 2019 and is expected to have formal effect by January 1st 2022.”

For severe cases, it is important to note that ICD-11 has adopted QE82.2 Personal History of Psychological Abuse  right along with Physical Abuse (QE82.0 and Sexual Abuse (QE82.1)
The relevant authors of DSM-5 say that parental alienation is in DSM-5 as child psychological abuse, as well as other places in DSM-5

DSM-5 diagnosis of V995.51 Child Psychological Abuse state this! 309.4 Adjustment disorder V61.20 Parent Relationship Problem V61,29 Child Affected by Parental Relationship Distress V995,51 Child Psychological Abuse, confirmed “Pathogenic Parenting”