Ehrlichia can also cause sinus problems...
So can viral infections...
And mold/fungal allergies are more common in winter, and dust allergies can occur year-round.
And some trees are starting to pollenate (yes, they start in winter).
I use Peaceful Mountain's Nasal Rescue - it is a colloidal silver nasal spray I found at a local health food store. It helps the unending sinus drainage/post nasal drip problems I've had for years (not from yeast in my case - I have very bad sinus allergies and bacterial infection problems).
Chronic Lyme Disease, Chronic Bartonella (clinical dx only), Gluten & Sulfite Sensitivity, Many Food/Inhalant/Medication/Chemical Allergies & Intolerances, Asthma, Gut issues (dysmotility, non-specific inflammation), UCTD ("Secondary Lupus-Like Syndrome"), Osteoporosis, chronic Lymphopenia, etc.; G-Tube; Currently weaning off TPN.
Meds: Pulmicort, IV Doxycycline, Heparin (to flush PICC line), Claritin, Singulair, Domperidone, Colloidal Silver (topically & nasally), probiotics, Liver support herbs, Ailanthus, digestive enzymes, homeopathy.