What causes a rash that seems when you wear jewelry?

Tip some latest eruption of neck Assessment: query by Steve D : What causes a rash when wearing jewelry My girlfriend at times has a rash around my neck, as she wears a necklace. The initial time, it was a wooden necklace, subsequent time, was the metal chain. The exact same kind of rash triggered. Greatest answer I know to steer clear of the eruption, it could simply be avoided, wear a necklace, but does anyone have any notion what could be causing this reaction, or if it is a sign of some

Itching Urticarial Rash