A human eye is one of the most sensitive and delicate organs in our body. Their sensitivity makes them prone to allergic reactions caused by some external triggers (allergens). Redness, itching, swelling or puffiness, burning sensation, and watery eyes are the signs of allergy.

An eye allergy is also called allergic conjunctivitis because of the severe immune response because of the direct encounter with an allergen, causing irritation in eyes. An eye allergy can be triggered by multiple factors, or elements acting as allergens.

They include:

• Pollens: From grass, weed, and trees. They are mostly seasonal. 
• Dust mites: Small microscopic bugs causing eye irritations. They can occur throughout the year.
• Mold: Small fungal spores present in the air. They occur mostly in damp or moist areas. 
• Dander: According to medical definition dander are "tiny scales shedding from animal or human skin or hair." Cat and dog dander are common allergens. Dander does not lead to an instant allergic response, it takes a year or two to develop an allergy. Once you have developed it, the best way to avoid it is staying away from direct contact with pets. 
• Irritants: Chemical, smoke, pollutants, scents, can also trigger eye allergy. Sometimes eye drops, and contact lenses can also cause allergy.
• Sun exposure: In some cases, a direct sun exposure can also cause allergy
• Heat and sweating: Sweating due to heat or hot climate can cause irritation in eyes, triggering an allergy. The hot environment also causes dry eyes.

Multiple, treatment options are available; however, the best way is to know your allergic trigger and avoid coming in direct contact with those allergens.