Mom,
it may be a food allergy. I'd say 'try' something but it would be an elimination game. you'd have to supplement for what you remove from her diet.
personally, I would start with gluten. It's a culprit in a lot of things - and it may be holding her back somewhere else in her body - that doesn't have a nose to show a symptom like a 'faucet'. But going gluten free is *hard* for some people.
Also, a decent pro-biotic (no, not the kind added to convenience foods like milk and yogurt) that is 10 million plus - with strains that don't die off in the stomach - would be important too.
Good luck,
M.