A UK review finds that asking people not to eat peanuts on a flight with a peanut allergic passenger has no benefit. Likely contamination is from the previous passenger contaminating the seat area and suggest allergic patients be allowed to board early to clean seat area with wet wipe. They also suggest epipens* are carried by airlines.
*Other devices are available that can be used to inject adrenaline / epinephrine in an emergency.
https://www.caa.co.uk/publication/download/17177
*Other devices are available that can be used to inject adrenaline / epinephrine in an emergency.
https://www.caa.co.uk/publication/download/17177