How do you know if your allergic to condoms?
Itching, irritating, redness, rash, and/or swelling.(edited for side note); I'm sorry, but if you are allergic to condoms I feel really bad for you...
It irritates your skin like itching, in some cases causes swelling and redness. There is no other way than trying.
It would be a latex allergy.http://www.mayoclinic.com/health/latex-allergy/DS00621
Most of the allergies come from the latex type. Try non latex.