Excess in any field of life, including truth-seeking, is detrimental to health and well-being.
An excessive concern with 'truth' can indeed turn one into a dogmatist who has cast aside all remnants of humility and respect for philosophical diversity. It can also darken one's worldview to such an extent as to make harming others seem advisable (see Consequences of Worldview).
As Nietzsche wrote
"He who fights monsters should look to it that he himself does not become a monster."It was indeed that thinker who thought that art was worth more than truth since compelling us to life or at least sometimes making life worth living, which cannot be said with the same force of dogged truth-seeking, especially when the latter takes issue with every aspect of the human condition.
At any rate, art has a capacity for more open-ended-ness and nuance than 'truth' discourses, whether of the philosophical or factual variety (see Factual and Philosophical Truth) and can sometimes prove to be a more effective way to resist and side-step immoral realities than head-on political activism (Refusing to Play the Chess Game).
Addendum - Nietzsche's view that 'we have art in order not to perish from the truth' is somewhat echoed by French author Marcel Proust's aesthetic solution to the problem of existence in the last instalment of his mammoth novel In Search of Lost Time (also known as Remembrance of Things Past). In that book, Time Regained, Proust writes
"Yet it is true that truth, which is not compatible with happiness or physical health, is not always compatible even with life."