'allergy-prone' originates from the combination of 'allergy' and 'prone', where 'allergy' refers to a hypersensitive reaction to certain substances and 'prone' means having a tendency towards something.

'Allergy' comes from the Greek word 'allergia', meaning 'other work', and 'prone' comes from the Latin word 'pronus', meaning 'leaning forward'.

Initially, 'allergy' referred to any altered reaction, but now it specifically refers to hypersensitivity. 'Prone' has maintained its meaning of tendency.