This is a very interesting question. No it's not true that the oil/ lubricant in a condom causes allergic reactions. The fluid in there has been scientifically tasted on humans before they are sold to anybody.
Unless someone has sensitive skin then they might react but that is a rare occurrence.In the case of a reaction I would advise that you go see a doctor at your nearest hospital or youth friendly health unit for assistance.
My child, It is important to remember that condoms protects from STIs, HIV and unwanted pregnancies during intercourse if they are used consistently and correctly . So, don’t allow such myths and misconceptions mislead you.