Hi Andrea,
For me they could be one of the signs of Candida. Mine is accompanied with oral thrush though, plus a few other signs / symptoms.

If you search Google for "Candida Symptoms" you will see 100's of different symptoms for it. One of the symptoms can even be leaky gut. You'll notice that there are a lot of causes for Candida too. It's also said that Candida feeds on sugar, and makes dairy fats hard to digest.

Interesting link:
http://www.thecandidadiet.com/foodstoavoid.htm
One more:
http://www.candidadiet.com/treatment/treatment_diet.shtml

Hope this helps,
Take care,
James.

HLA-B27+, JRA diagnosis in 1981, re-diagnosed as AS in 1988. Also iritis, colitis, and psoriasis. NSD + low carb helps me. My health makes it hard for me to post in a timely way.