> Is the damage from the fumes different than the sensitization
> from skin contact.

George they can be quite disimilar. The organic solvent fumes are absorbed rapidly from the lungs (after they've damaged some alveoli) and can be deposited in the nonpolar high lipid containing liver cells and myelin sheath (insulation layer) of nerve cells in the brain -- they really can kill brain and liver cells. The sensitization from skin contact is mediated by an immune response (allergic reaction) and the damage is caused by your own defense mechanism going haywire rather than directly from the offensive chemical. This immune system response can also be triggered by inhaling the offensive chemical in a sensitized individual (just ask anyone foolish enough to try and burn poison oak or ivy and has inhaled the smoke!!)

In short, everyone who inhales enough fumes can mess up their liver and brain (as in dummies who inhale paint for a high). Only individuals with an allergic sensitization will develop symptoms from contact exposure.