It's that time of year again, when along with an improvement in the weather, millions of people are welcoming the sniffling, sneezing and itchiness of seasonal allergies.
The number of people who suffer from these airborne allergies, a condition known as allergic rhinitis, has been on the rise in recent decades, especially in European cities, where pollen is sticking around for longer than usual.
Fortunately, for allergy sufferers across the globe, there is hope.
How allergies work
The body creates an allergic response by what's called an allergen — for people with seasonal allergies, that would be pollen from trees, grasses and weeds.
When that pollen makes it into the nose of an allergic person, their immune system mistakes it for a harmful foreign invader and goes into overdrive.
It releases antibodies to attack the allergen, which prompts cells in the person's nose, throat and lungs to release chemicals such as histamine, which is what leads to that sniffling and sneezing, or in more severe cases, asthma attacks.
There is no cure for seasonal allergies, so treatments have typically focused on managing the symptoms or avoiding allergens in the first place.
For medicinal treatments, the two usual standbys are antihistamines, such as Benadryl or Allegra, along with steroid nasal sprays like Flonase or Nasacort. There is also a new nasal spray that contains both.
For those who suffer from allergies, tablets containing small doses of the allergen are dissolved under the tongue either daily or a few times a week for a period before and during allergy season. It's based on the idea that by exposing the immune system to small doses of the allergen, you can make your cells more tolerant to it.
This is a whole new type of desensitization which works in principle the same as allergy shots. But they are easier to take, probably safer, and it's done at home instead of the doctor's office It makes it quite easy for children and people who don't like needles to desensitize themselves.
Some studies also suggest that after about three years of daily treatment, sublingual immunotherapy provides a long-lasting effect for many people, basically reprogramming the body to be more tolerant of the allergen.
Another type of treatment, specifically for people with severe asthma, blocks the communication pathways in an allergic response. A patient would receive a shot of antibodies that target the "communication molecules" that lead to inflammation.
That cost is high and it may be reasonable for people with severe allergies or asthma, but probably doesn't make sense for the casual allergy sufferer.
New research is showing some early promise for a potential allergy vaccine. The treatment works by essentially teaching the immune system how to respond to allergens in a normal way.
Unlike other immunotherapies that only work on specific allergens, the molecule would be effective for all of them — so it wouldn't matter if you're allergic to pollen, dust, cats or dogs.
Previous studies also showed that researchers could use the molecule to reprogram the immune systems of mice who were already allergic to pollen, a finding that could eventually pave the way towards finding a cure.
The treatment is still in animal testing phase and has a long way to go before it even reaches human clinical trials.