To survive, an adult head louse must feed on blood. They can live for approximately 30 days on a person's head. If they fall off, they will die within 1 to 2 days.

What is eating my hair?

Trichophagia is the compulsive eating of hair associated with trichotillomania (hair pulling). In trichophagia, people with trichotillomania also ingest the hair that they pull; in extreme cases this can lead to a hair ball (trichobezoar).

Can insects eat hair?

While human hair isn't a preferred food source, cockroaches will eat almost anything. Hair contains lipids and sebum, which can sustain cockroaches for a short while. They're far more likely to eat shed hair rather than hair off your head under the cover of darkness as it's less risky.