Red snake bite in a dream can be a cause of an external stimulus.
For anyone, recently in real life experienced a feeling of bleeding gums, or an eating of a rare done bloody stake, or a bite of a blood sucking mosquito can be a source of dreaming about bite by red snake. Any biting feeling from life can be an inspirational cause for your dream.
For a woman, a sudden menstrual pain in a belly can be an external stimulus for a dream about a bite of red colored snake.
For a man, a sharp painful feeling in a body part full of blood can be seen as a cause for the dreams about the red long limbless biting reptiles. And the pain can be felt up to few times during a night.
Also, if closed eyes being touched unexpectedly by red first light of rising sun early in a morning, this external feeling can be used by subconscious mind for a disturbing dream of a red color snake biting you or someone else.