My seasonal allergies (aka Hay Fever) are flaring up and I'm caught without my medicine. What can I do for short-term relief?
The best right now fix I've had is to wash your face and keep rinsing with clean water for a few minutes. This helps with the itchy eyes and removes irritants from your skin. Any other area of the body you can wash also helps. Best if you can actually take a shower and change into clean clothes, but the face wash is best for situations where that isn't possible.
I have a friend who wears a SCUBA mask with a HEPA filter on it when the birch trees are active. He looks like Darth Vader, but he experiences no allergies.
Local honey. Go to a farmers market/local farm/natural store in your area. Try to find honey (preferably honey in the raw) that is farmed within 100 miles of you. The closer the better. The pollen in the honey will contain the things your allergic to (sounds counter productive) in a level that your body can handle, and will help you get over your allergies. It may not completely get rid of them, but it will help. Also helps with sore throat/cough.
If you have a car with air conditioning and air re-circulating, switching these both on should filter pollen out of the air. Sorry it's not much use whilst not in a car, but it may offer some relief.
You may find it beneficial to try a Neti Pot.
People often use Neti Pots to flush the pollen out of some of their sinus cavities.
If you choose to try a Neti Pot, make sure you use an appropriate solution mixture (typically containing pure sodium chloride and pure aluminum-free sodium bicarbonate) and distilled water. Never use tap water, well water, or regular bottled water, as you don't want to introduce contaminants/bacteria into your sinus cavities.
Some people have experimented with using Himalayan salt in a Neti Pot, but it is unknown whether or not that is a safe practice.
Take a placebo, and try to control any significant psychological factors. Psychology is an important factor in allergies because they are basically overreactions of a bored immune system. Basic things such as work-related stress, being in love etc. can have a significant impact. So if you were surprised by unusually strong hay fever, you might consider manipulating your psychological state:
Of course manipulating your psychological state could also make things worse if you don't have a good idea of what it will do to your allergy.
Also, this would be the best time for getting some kind of proper infection so that your immune system has real work to do. I am just not sure how that would translate into something you can actually do...