There is no possible physiological route that would lead to symptoms from
hand contact with pure lactose. Lactose intolerance comes only from the lack of
digestion of lactose. Lactose cannot go through the pores to the bloodstream
and if it did by magic absolutely nothing would happen because of it. It's
extremely unlikely that you could get enough into your system by swallowing powder
that floated through the air, either.
It is possible to have a reaction to dairy proteins through contact, however.
If you're making a formula then you probably have dairy proteins in it
totally separate from the lactose. Would enough dairy proteins be present in the
wafting of the powder to cause a reaction? Probably not. If you could be affected
by that small an amount of protein then you would know it by now because you
would be reacting all the time to traces of dairy. And you wouldn't get
digestive symptoms that could be confused with lactose intolerance, but rashes and
other skin problems.
So - most likely it's just a coincidence, or even a psychological affect from
the knowledge that you're handling lots of lactose.
Steve Carper
Steve Carper's Lactose Intolerance Clearinghouse
http://ourworld.compuserve.com/homepages/stevecarper
Planet Lactose Blog
http://planetlactose.blogspot.com