If you sneeze and sniffle your way through pollen season, or experience hives, itching or swelling when you eat a certain food or get stung by an insect, then you're no stranger to allergies. "An allergy starts when the immune system mistakes a normally harmless substance for a dangerous invader," explains the Mayo Clinic. While people often prove allergic to all kinds of things, there are numerous allergens that commonly affect sufferers.
Inhalants
Some allergens are airborne and get into our systems when we breathe them in. The most common airborne allergy triggers are pollen, animal dander, dust mites and mold. Someone who's allergic to inhalants has allergic rhinitis, and if someone has an allergy to pollen, they have hay fever. Trees, weeds, grasses and flowering plants produce pollens. You can find pollen in the air any time between spring and fall, depending on the plant and geographic location. Pets like cats and dogs shed animal dander when they clean themselves and dust mites live off bacteria and dead skins cells that collect in dust around the house, and found in carpeting, bedding and upholstered furniture. Mold grows in damp areas, both inside and outside and gives off spores that can cause allergic reactions when either inhaled or touched. Allergy symptoms to these types of allergens include congestion, a runny nose and watery, itchy or swollen eyes.
Food
Obviously food gets into our bodies when we eat it, and food allergies can cause hives or a tingling or swollen mouth, tongue, throat or face. In severe cases, food allergies cause anaphylaxis, a life-threatening reaction that includes swollen airways, shortness of breath, nausea or loss of consciousness. The most common food allergies include, "peanuts, tree nuts, wheat, soy, fish, shellfish, eggs and milk," says the Mayo Clinic.
Other Allergens
Other common allergy triggers get into our bodies by being either injected, or absorbed through the skin. Injected allergens include, "medications delivered by needle like penicillin or other injectable drugs, and venom from insect stings and bites," according to the Asthma and Allergy Foundation of America (AAFA). Drug allergies and insect sting allergies can both cause itching, hives, extreme swelling, wheezing, chest tightness or anaphylaxis. Allergens absorbed by our skin include latex--which is made from rubber tree sap--and plants like poison ivy, poison oak and poison sumac. The most common symptom for those types of allergies is a contact dermatitis rash, says the AAFA.
