I Googled it. It's almost the same as trichotillomania, which is pulling out hair, but thricophagia is the eating of hair, even while attached to the head, and swallowing it. (It's not the same as mindlessly chewing on the ends of one's hair, like some children do, but actually eating it.)

Trichophagia - Wikipedia, the free encyclopedia
Trichophagia (Greek: τριχοφαγία, from τρίχα, tricha “hair” + φάγειν, phagein “to eat”) is the compulsive eating of hair associated with trichotillomania (hair pulling).[1] In trichophagia, people with trichotillomania also ingest the hair that they pull; in extreme (and rare) cases this can lead to a hair ball (trichobezoar).[2]

Another defining page, perhaps a little clearer:
Trichophagia | TrichStars.com
Trichophagia is related to another compulsive disorder, trichotillomania. Both trichophagia and trichotillomania involve compulsions surrounding an individual’s hair. Trichotillomania sufferers will just pull out their hair and will not eat it. Trichophagia sufferers will not always pull out their hair, but will consume it when it is still attached to their head. Many sufferers of trichophagia start out with trichotillomania

You might want to check out the main page, at trichotillomania | TrichStars.com.