Allergens responsible for allergy vary from residence to residence and from region to region. For example, cockroaches are a very important cause of asthma among inner-city populations, while in the mountain states, cats and dogs cause more allergy. Molds have been reported to be the dominant asthma-related allergens both in the humid Pacific Northwest, and in dry areas like Arizona where they grow in the water of cooling systems. One thing all these allergies have in common is the discomfort and misery they cause.
The four major indoor allergens in the United States are dust mites, cockroaches, pet dander, and mold spores. In vermin-infested homes, mouse and rat allergens may be involved. Pollen and mold spores are the major outdoor allergens responsible for seasonal asthma.
Allergy is just one of several immunity dramas being played out currently as nature fights back against “progress,” along with the emergence of HIV and antibiotic-resistant strains of bacteria. All show that there are mechanisms, whether actually “intelligent” or not, that fight hard to survive in the face of assault by science and technology.
The overall fight between medicine and disease is constant, and while medicine has held an advantage since the invention of penicillin, that lead is now threatened. The battle between allergy and medicine, on the other hand, has been very close for a long time, and it is not always clear who is ahead.
Allergens are usually made of proteins from such living things as the skin of animals, referred to as dander, dust, tiny insect parts, mold spores, and pollen. Some of these are perennial, around all the time, and some are seasonal, around only at certain parts of the year. For example, ragweed pollen, a major allergen, is only around in the late summer when the ragweed itself is flowering (although the season is longer in the South than in Northern states), and the air echoes with the sound of sneezing.
Newly mown grass is highly allergenic, so anyone who wants to instill a sense of responsibility in their children by assigning regular chores should try to find another task for kids with allergies.
Cleaning the basement is probably not a good one either because of dust and molds.