Wearing gloves over a prolonged period of time will cause swelling of the skin whch is then less resistant against chemicals. Furthermore the warm and humid atmosphere in the glove favours formation of pathogens which may cause skin disorders. If the skin is exposed permanently to the atmosphere in a glove it will degenerate (eczema). According to the "Verordnung zur Arbeitsmedizinischen Vorsorge" in Germany an occupational-medical health examination has to be offered if gloves are worn more than 2 hours per day. If gloves are worn 4 or more hours per day this examination is obligarory.
Unproper usage of gloves may be more harmful than working without gloves!