Colophony is a chemical substance, which is proved to be highly allergic.  In the sport of handball, colophony is used in certain brands of handball glue.  Can you imagine that players voluntarily rub an allergic substance on their hands - and they do it 3-4 times a week, each time letting the allergic substance attack the skin for maybe 2-3 hours.

How many players have given up playing handball because they suddenly developed allergic reactions?

Read the below article, which will give you some more background to colophony and also refer to a practical test, which proved the allergic force of handball glue based on colophony!!!

Some brands of handball glue are marketed as 'dermatological tested'.  Analysis of these products has proven that they contain colophony to a large extent, and such products could cause severe allergic reactions.

The issue of allergic substances in handball glue has been presented to the European Handball Federation (EHF), and they are evaluating the technical aspects in more detail.