Ironically, the synthetic rubber called neoprene was originally used as an acceptable alternative to latex, which could trigger serious allergic reactions in certain wearers. Neoprene is often found in medical braces, protective gloves, elastic fabrics and wetsuits.
It is very possible for a person to become allergic to neoprene and experience a form of contact dermatitis. Scuba divers and surfers have been known to suffer from a rash caused by the neoprene used in some wetsuits, and wearers of elastic bandages and braces may discover signs of contact dermatitis wherever the neoprene remains in contact with their skin.
The reason you may be allergic to neoprene could be a sensitivity to several different compounds used to cure and harden the natural rubber. Traces of these chemicals can remain in the finished neoprene product and cannot be easily removed through ordinary washing.
When someone is truly allergic to this rubber, any extended contact could cause a reaction. It is possible that you might actually be sensitive or allergic to a medical cream or other substance placed on the neoprene, not the neoprene itself. If you have a reaction on your skin after prolonged contact with a neoprene glove, wetsuit or brace, examine the object for any other contaminants or substances which could trigger a similar reaction.
Testing to see if you are indeed allergic to neoprene usually requires a visit to a local allergy clinic for a specific patch test. This is different from a scratch test, so you'll want to tell the doctor about your contact with neoprene. There are at least 6 different compounds used to cure and harden natural rubber, so the allergist may need to examine the actual object which may have triggered the reaction. A neoprene allergy patch test is not always on the standard menu, so your allergist may have to arrange for a more thorough battery of tests.
If you are indeed allergic to neoprene, the best solution may be to avoid it as much as possible. There are modern wetsuits which have either eliminated neoprene altogether or minimize its contact with the wearer through layering. An application of a chemical barrier such as Vaseline may also minimize direct contact with neoprene braces or bandages. Avoid using athletic shoe liners which may contain neoprene and check the labels of active sportswear and swimsuits for the presence of neoprene.
If you do suffer an allergic reaction to neoprene, you may want to take antihistamine medications such as Benadryl® and allow the rash to heal naturally. Some medical professionals discourage the use of over-the-counter anti-itch creams until the root cause of the dermatitis can be determined. The wrong medication may actually worsen the effects of a neoprene allergy.