Allergens

Nowadays most people spend more than 90% of their lives indoors. Over the past 30 years, the home environment has changed enormously with the introduction of soft furnishings, fitted carpets, and central heating. Indoor ventilation has decreased—the rate at which indoor air is exchanged for fresh air is now 10 times lower than it was 30 years ago, with a considerable increase both in humidity and in concentrations of indoor pollutants and airborne allergens. As exposure to allergens is an important cause of symptoms in sensitised patients, reducing exposure should improve disease control

Every home harbors potential allergens, from the rare to the ubiquitous, but these five are the most common triggers for indoor allergies:

• Dust: Dust can be made up of dozens of things, including tiny bits of plants, skin, soil, insects, food, fibers, and animal matter. Any one or more of these minute substances could trigger indoor allergies.
  
  
• Dust Mites: As you may have guessed, dust mites thrive on dust. And, dust mite droppings are the most common trigger of allergy and asthma symptoms, according to the American Academy of Allergy, Asthma, & Immunology. Although you’ll find dust mites all over the house, they concentrate in areas rich with human dander (dead skin flakes) and high humidity: bedrooms, carpets, bathroom rugs.
  
  
• Mold: Mold and mildew thrive in high humidity, such as your steamy bathroom or chilly, damp basement. Once they take hold, mold and mildew shed tiny spores -- and these spores trigger indoor allergy symptoms.
  
  
• Pet Dander: If you have pet allergies, you’re not actually allergic to cat or dog hair. Instead, the allergic reaction is caused by a tiny protein in an animal’s saliva. Even homes without pets may contain dander. That’s because pet dander is sticky and light. It clings to clothes, shoes, and hair. Thus, pet dander can be found in boardrooms and classrooms, as well as at home.
  
  
• Cockroaches: Like dust, roaches can be found almost everywhere. As with pets, it’s not the roach itself that triggers indoor allergies. Instead, the potential allergen is a protein found in the cockroach’s droppings