It can be a bummer when gorgeous weather beckons you to go outside and you suddenly find your adventurous spirit hampered by your one true enemy: allergies. Why is it that harmless plants seem to attack our senses? And why are only some of us affected?
In this TED-Ed lesson by Eleanor Nelson, we learn that our immune systems basically just confuse harmless pollen and mould spores with something potentially dangerous like bacteria, and the unpleasant allergic reaction we experience is our body on the defence. Allergies tend to run in families, so there might be a genetic component as to which allergens affect you, and where you grow up also plays a factor. Being exposed to allergens as a baby makes you less likely to develop an allergy to it later on (but that doesn't mean you should send your baby out rolling in the weeds). The hygiene hypothesis posits that a lack of childhood exposure to microorganisms and parasites causes the immune system to over-eagerly attack harmless substances.
The simplest way to combat your allergies are antihistamines, which diminish the inflammation response. Apparently hook worms also can be used to treat allergies (which also might be why allergies are less common in developing countries where hook worms are more prevalent), but you probably shouldn't trade your allergies for worms just yet.