The most common allergens that cause Respiratory Tract Infections are:

Airborne allergens

Contact with proteins found in certain airborne particles may trigger airbone allergens like Allergic Rhinitis. These allergic proteins can come from a variety of sources:

Nature:

• Pollen (Small, powdery grains of flowering plants that can easily become airborne)
• Trees
• Grass
• Weeds
• Moulds: Alternaria, Cladosporium (Tiny fungus spores that can become airborne, usually found in damp areas, basements and bathrooms)
• Insects

Household allergens

• Dust mites (Microscopic insects that inhabit household dust and are found indoors, in areas where air circulation is poor and on surfaces like carpets, bedding and stuffed animals)
• Cockroaches (Droppings, eggs, saliva and small pieces of the outer shell of cockroaches)
• Pets (Tiny scales or particles from the skin of a pet, usually shed by dogs and cats)
• Moulds and bacteria in fans, humidifiers and air conditioners
• Mildew

Occupational allergens

• Your work environment may expose you to substances, chemicals and conditions that may make you uncomfortable. Some of these may be related to:
• Agricultural and food-processing: grain dust (storage mites), hay dust, soy, castor, coffee beans, sunflower seed, cottonseed, flaxseed, wheat flour, rye flour, shell fish, fish, woodworks
• Chemical Plastics (eg, diisocyanates, trimelitic anhydride), metals (eg. nickel, platinum), pharmaceuticals, detergents (Bacillus subtilis enzymes)
• Textile industry: Byssinosis (cotton bract dust)
• Cosmetic products: Perfumes, hair dyes, bleaches, cologne, soap, candles, skin lotions, sunscreens, deodorants, lipsticks. These could result in severe reactions like shortness of breath, cold-like symptoms or worsening asthma symptoms
• Laboratory animals : rodent urine