Tricyclic antidepressants (TCAs) are generally better than selective serotonin reuptake inhibitors (SSRIs) and serotonin and norepinephrine reuptake inhibitors (SNRIs), for typical people who have mast cell disorders. In addition, the inhibitory effect of tricyclic antidepressants on mast cells has been shown to improve mood and physical symptoms of MCAS, compared with other antidepressant classes.
Selective serotonin reuptake inhibitors (SSRIs) and serotonin and norepinephrine reuptake inhibitors (SNRIs) are generally sub-par for typical MCAS patients.
TCAs and SSRIs/SNRIs are both effective in treating a wide variety of anxiety disorders. SSRIs/SNRIs in many people (not mast cell patients) have somewhat-better safety and somewhat-better tolerability, which is why doctors who don't know MCAS tend to start with SSRIs/SNRIs rather than TCAs. As you know, everyone's individual, and as you probably also know, psychiatric medications often involves trying various options to figure out what works well.
TODO: add more details about why serotonin is a problem.