Ignore them.

Narcissism comes in a spectrum, it's not just on or off, there or not. Symptoms of narcissistic personality disorder from Mayo Clinic.

1. Expect special favors and unquestioning compliance with their expectations
2. Have an inability or unwillingness to recognize the needs and feelings of others (includes inability to tolerate that people have different opinions of them)
3. They crave attention even if they have to belittle others to do it. Belitting others is common to get their attention since they have very little empathy for others.

From PsychCentral:

1. lack of empathy, arrogance
2. People with narcissistic personality disorder often display snobbish, disdainful, or patronizing attitudes.
3. It typically leads to significant distress or impairment in social, work or other areas of functioning. The pattern is stable and of long duration, and its onset can be traced back to early adulthood or adolescence.
4. Has a very strong sense of entitlement
5. Lacks empathy, e.g., is unwilling to recognize or identify with the feelings and needs of others

From Psych Today:

1. Shows arrogant, haughty [rude and abusive] behaviors or attitudes.
2. They are highly reactive to criticism. Or anything they assume or interpret as negatively evaluating their personality or performance. (Because they have very low self-esteem).
3. Can be inordinately self-righteous and defensive. Needing so much to protect their overblown but fragile ego, their ever-vigilant defense system can be extraordinarily easy to set off.
4. React to contrary viewpoints with anger or rage. In fact, this characteristic is so common in narcissists that it’s always surprised me that DSM doesn’t specifically refer to it among its nine criteria.
5. Project onto others qualities, traits, and behaviors they can’t—or won’t—accept in themselves.

Keep in mind the DSM V is not the be-all-end-all source of information. It's just a politically motivated book used by insurance companies.