Uncommon Household Allergens: 5 Hidden Allergens

Learn the five uncommon, some potentally dangerous household allergens.


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Are they lurking in your home?

An allergen is any substance that induces altered bodily reactivity or exaggerated reactions. Each individual responds to allergens uniquely. Common allergens include pollens, dust, animal dander, molds, bee stings, wool and other natural fibers, and some foods. Because these target the nose and respiratory system, skin, eyes, ears, and gastrointestinal system, people who react to these allergens may sneeze, wheeze, cough, scratch, ache, and look puffy.

Another type of allergen is chemicals and additives found in foods and the environment. Reactions to these vary widely and can seem unrelated to each other; responses may include migraine headaches, confusion, memory loss, personality changes, mood swings, hyperactivity and depression.

Everyone has the potential to be allergic. Whether or not you respond to particular allergens has to do with your individual tolerance threshold. You can be repeatedly exposed to something with no problem, then one day that very same substance can be the straw that breaks the camel’s back—your body is exposed to more than it can take and you have an allergic reaction.

Foods and natural allergens do not generally harm the body beyond their annoying symptoms and are safe for otherwise healthy people to be exposed to. Most chemical allergens, on the other hand, do cause harm to healthy bodies; everyone should avoid them.

#1 House dust

House dust contains a mixture of potential allergens, including cotton lint, feathers, animal dander, bacteria, food particles, bits of plants and insects, and other allergens specific to an individual home.

The actual allergen in house dust, however, is the protein waste product of the dust mite. Dust mites live in bedding, drapes, upholstered furniture, and carpets. They thrive in summer and die in winter, but in a warm, humid house they can continue to live through even the coldest months.

If you are allergic to dust, take every precaution to avoid it; if you are otherwise healthy, regular dusting and vacuuming should be enough to prevent dust allergies.

#2 Mold

Mold is ubiquitous—there is always a little mold in the air and on many surfaces. Molds can easily enter homes through doorways, windows, heating ducts, ventilation systems and air conditioning systems. Spores in the air can also land on people and animals, who bring them indoors.

Mold becomes a problem only in areas where it can proliferate because of excessive moisture from such sources as leaky pipes, a leaking roof, or even water seeping from potted plants. Cellulose materials, including paper and paper goods, cardboard, ceiling tiles, wood, and wood products, are particularly conducive to the growth of some molds, while ­others prefer dust, paints, wallpaper, insulation materials, drywall, carpet, fabric and upholstery.

The most common indoor molds are cladosporium, penicillium, aspergillus, and alternaria. None of these are toxic, but all can act as allergens. The presence of large amounts of mold can trigger an extreme mold allergy where none existed before, so it is better not to live in a moldy house.

To minimize mold, keep rooms dry, warm, and light. Mold is a living organism that will only grow in cold, dark, damp places. If you have a recurrent mold problem, bring more light, heat, or fans to move the air.

#3 Seasonal pollens

Unlike dust and molds, which can be present year-round, pollens come indoors during certain seasons, particularly spring and fall. Weeds, trees, and grasses produce natural pollutants at particular times of the year when their tiny flowers discharge billions of pollen particles.

Plant pollens that are carried by the wind cause most allergies. The flowers used in most residential gardens are pollinated by bees, wasps, and other insects, so it is likely that whatever plants are ­causing your allergic reaction are hidden far away.

The telltale symptoms of pollen allergies are ­persistent itchiness and runny mucus in the eyes and nose. Allergies are different from the common cold in that there is no fever and mucus is thin and clear rather than thick and yellow.

Unfortunately, if you have a problem with seasonal pollens, you can't eliminate the offending particles at the source. But you can keep your indoor environment pollen-free by keeping windows closed for the weeks or months when pollens are at their worst, or using an air filter that is specifically designed to remove particles.

#4 Perfume

Perfume is the most common allergen in personal care products. When a label says “hypoallergenic,” the product may contain other allergens, but generally not perfume.

Both synthetic and natural fragrances can be allergens. Read labels carefully, and if fragrance is a problem for you, test both natural and synthetic fragrances. You may find you can tolerate one or the other.

Perfume may be hidden in cleaning products (particularly air fresheners), all kinds of skin care and shaving products, soap, baby products, contraceptives, cooking fuel, disposable diapers, facial tissues and toilet paper, detergents, sanitary products and shoe polishes. Use your nose to sniff it out.

#5 Formaldehyde

Formaldehyde is a common chemical hidden in numerous household products, from adhesives, cosmetics, deodorants, detergents, fertilizers, paints, particleboard, plastics, and textiles, to products as tiny as the gelatin capsule that holds vitamins.

One symptom of formaldehyde exposure is ­insomnia, which can be cured by removing polyester/ cotton or no-iron cotton sheets, both of which are covered with a permanent press formaldehyde resin.

The National Academy of Sciences estimates that 10 to 20 percent of the general population may be susceptible to irritation from exposure to formaldehyde at extremely low concentrations. Symptoms include coughing, swelling and irritation of the throat, watery eyes, headaches, rashes, excessive thirst, nausea, and disorientation.

If you suspect a formaldehyde problem, you can get more information at www.epa.gov/iaq/ formalde.html.