It's true that pine pollen allergy is less common than other pollen allergies. We don't test for it in our office, either, for that reason. However, that doesn't mean your daughters can't be allergic to it. Let's back up for a moment, though. You say that they had allergy tests done. These could have been either blood tests or skin tests for pine-specific IgE. Skin tests are more likely to detect a pollen allergy.
Having skin testing performed, if you haven't already, would be my first suggestion. However, pine is not a standard extract in most allergy offices, as I mentioned. Perhaps you could check on this beforehand, or ask if you could pay for a small bottle of pine extract to be used in the testing. Make sure you have skin testing done by someone who is trained (usually an allergist, but some ENTs know how to do it as well) and can recognize and treat possible allergic reactions (which are rare but can be dangerous if not handled properly).
Another possibility is that your daughters are allergic to something that was not picked up by their tests. Dust mites, molds, cockroaches, and mice are common in new homes, and may be present even without your knowing it. Also, if the previous owners had cats and your daughters are allergic, this could be causing their reactions because cat allergens take years to wear out of carpets and furnishings. You should review the test results to see if your daughters were tested for cat allergies.
Another point to clarify is whether the ENT physician thinks your daughters' problems are definitely allergic in nature. Allergic noses are swollen and pale, and allergic people often have eye symptoms too. However, your daughters could have other conditions that cause rhinitis (nasal inflammation), such as irritation from a heating system or a chlorinated swimming pool. Ask the ENT for his or her thoughts on other possible explanations.
Finally, it's worthwhile to consider having your daughters retested in a year or so. When allergies are truly new, a person's skin sometimes takes longer than his or her nose and eyes to show allergic symptoms. An allergy might just take time to become detectable in this way. I hope these suggestions help you make sense of the situation.
Learn more in the Everyday Health Allergy Center.