I have a 10 month old girl her mother has deathly allergies are these hereditary and when could an epi pen be used on a baby in the event of anaphylax?

Allergies: Allergies can be heridatory. But, environmental allergies are the most common. Food allergies can have a role too. Epi pen is used in cases of anaphylactic reaction, like breathing difficulty, turning blue, or tingling of numbness on the back of throat.

Workup report sx: Allergy testing can be performed but it is more accurate later in life. A blood test panel called CAP for aero allergens and foods can be performed. Allergic reactions among infants can be very subtle, so close observation for any changes in the baby's appearance or activity should be reported to your pediatrician. I would advise having children's benedryl at home and knowing the correct dosage/wt

It cannot: The mother's epipen (epinephrine) is a different (higher) dose than would be given to the 10 month old girl. Using the mother's epipen (epinephrine) could be very dangerous. However, in an emergent situation (baby turning blue or not responding due to suspected allergen exposure) without emergent medical services, then it could be used only as a "last-chance" measure to save life. Baby must get her own evaluation.