The most common symptoms of indoor allergies are runny nose, eye irritation, skin irritation, cough, congestion, aggravation of asthma, headache, fatigue, respiratory ailments and flu-like reaction.

Whether or not symptoms develop in people exposed to indoor allergens depends on the nature of the indoor allergens, the amount of exposure, and the susceptibility of exposed persons. Susceptibility varies with the genetic predisposition (e.g., allergic reactions do not always occur in all individuals), age, state of health, and concurrent exposures.

For these reasons, and because measurements of exposure are not standardized and biological markers of exposure to allergens are largely unknown, it is not possible to determine "safe" or "unsafe" levels of exposure for people in general.

• House dust allergy symptoms
• Mold (Fungi) allergy symptoms

HOW DO I KNOW IF I HAVE AN ALLERGY?

If you think you may have an allergy to any of the components of house dust, consult a board certified allergist-immunologist. To pinpoint the cause of your symptoms, the allergist will ask detailed questions about your work and home environments, family medical history, frequency and severity of symptoms, exposure to pets and a variety of other questions. Sometimes the history will reveal obvious triggers, like someone who develops symptoms every time they are around a certain animal. More often though, the history may suggest triggers, but it may not be obvious in identifying the exact ones.

Sometimes the medical history may not suggest any triggers, yet allergy may be the cause. In this case, your allergist finds out what you are allergic to by doing skin tests. Skin tests involve either pricking the skin (prick tests) or injecting into the skin (intradermal tests) with different allergens and observing for a reaction. A positive reaction (a raised welt with redness around it) may indicate that you are allergic to that allergen. Occasionally, your allergist may order a blood test in addition to the skin test to confirm the diagnosis of allergy. The blood tests are generally less sensitive than skin testing.

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HOUSE DUST ALLERGY SYMPTOMS

Many people recognize allergy symptoms such as a runny or stuffy nose, itchy, watery eyes and sneezing (allergic rhinoconjunctivitis) from dust exposure related to common household chores such as vacuuming, sweeping, and dusting. House dust exposure can also trigger asthma symptoms such as wheezing, coughing, chest tightness and shortness of breath.

Why does house dust cause allergic reactions?

House dust is a mixture of many substances. Its content may vary from home to home, but the most common allergy triggers are:
• Dust mites
• Cockroaches
• Fungi (Mold)
• Animals

Any of these allergens can cause a response in the immune system which results in the production of a special antibody (Immunoglobulin E or IgE). IgE brings
about an allergic inflammatory response. Exposure to only small amounts of the offending allergen can cause allergy symptoms.

High levels of exposure to dust mite are an important factor in the development of asthma in children. People who are allergic to dust mites react to proteins within the bodies and feces of the mites. These particles are found mostly in pillows, mattresses, carpeting and upholstered furniture.

Dust mite-allergic people who inhale these particles frequently experience allergy symptoms. There may be many as 19,000 dust mites in one gram of dust, but usually between 100 to 500 mites live in each gram. Each mite produces about 10 to 20 waste particles per day and lives for 30 days. Egg-laying females can add 25 to 30 new mites to the population during their lifetime.

Many houses have dust that contains parts of cockroaches. This is most common in older, multifamily housing and in the southern United States where complete extermination of cockroaches is very difficult. Individuals allergic to cockroach protein, particularly those with asthma, tend to have increased symptoms if they live in such houses. You do not have to actually see cockroaches to have a problem. The allergen is derived from saliva, fecal material, secretions, skin casts, and body parts.

Molds spread by producing spores that can become airborne when they are disturbed directly or by air currents. These spores end up on surfaces where they grow. Dust from mold-contaminated houses can cause allergy symptoms if a person who is allergic to the mold inhales them. Some molds produce bad odors. These odors may be irritating (like any strong odors) without actually causing an allergic response.

Cats and dogs are the most common cause of animal allergy, but any warm-blooded animals (guinea pigs, hamsters, etc) can trigger an allergy symptoms. It’s not just the hair or skin particles that contain the allergens, but also the urine and saliva. Mice can trigger allergies if present in sufficient numbers.
Allergens from domestic animals, especially cats, may be carried on the clothing of pet owners outside the home into the work place and schools. In fact, cat allergen, is one of the most common allergens found in the dust in schools.

What can I do to relieve house dust allergy symptoms?

Once your allergy triggers have been identified, steps should be taken to avoid them. Research has confirmed that targeted avoidance (environmental control aimed at relevant triggers) can be as effective as medications in reducing symptoms. The usual case requires targeted avoidance, medications prescribed by your allergist, and in many cases, specific allergen immunotherapy (allergy shots) to bring the problems under control.

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MOLDS (FUNGI) ALLERGY SYMPTOMS

Some people are sensitive to molds. For these people, exposure to molds can cause symptoms such as nasal stuffiness, eye irritation, wheezing, or skin irritation. Some people, such as those with serious allergies to molds, may have more severe reactions. Severe reactions may occur among workers exposed to large amounts of molds in occupational settings, such as farmers working around moldy hay. Severe reactions may include fever and shortness of breath. Some people with chronic lung illnesses, such as obstructive lung disease, may develop mold infections in their lungs.

There have been reports linking health effects in office workers to offices contaminated with moldy surfaces and in residents of homes contaminated with fungal growth. Symptoms, such as fatigue, respiratory ailments, and eye irritation were typically observed in these cases. Some studies have suggested an association between SC and pulmonary hemorrhage/hemosiderosis in infants, generally those less than six months old. Pulmonary hemosiderosis is an uncommon condition that results from bleeding in the lungs. The cause of this condition is unknown, but may result from a combination of environmental contaminants and conditions (e.g., smoking, fungal contaminants and other bioaerosols, and water-damaged homes), and currently its association with SC is unproven.

Inhalation of fungal spores, fragments (parts), or metabolites (e.g., mycotoxins and volatile organic compounds) from a wide variety of fungi may lead to or exacerbate immunologic (allergic) reactions, cause toxic effects, or cause infections.

Illnesses can result from both high level, short-term exposures and lower level, long-term exposures. The most common symptoms reported from exposures in indoor environments are runny nose, eye irritation, cough, congestion, aggravation of asthma, headache, and fatigue.

Whether or not symptoms develop in people exposed to fungi depends on the nature of the fungal material (e.g., allergenic, toxic, or infectious), the amount of exposure, and the susceptibility of exposed persons.

Immunological Effects

Immunological reactions include asthma, HP, and allergic rhinitis. Contact with fungi may also lead to dermatitis. It is thought that these conditions are caused by an immune response to fungal agents. The most common symptoms associated with allergic reactions are runny nose, eye irritation, cough, congestion, and aggravation of asthma.11, 12 HP may occur after repeated exposures to an allergen and can result in permanent lung damage. HP has typically been associated with repeated heavy exposures in agricultural settings but has also been reported in office settings.
Exposure to fungi through renovation work may also lead to initiation or exacerbation of allergic or respiratory symptoms.

Toxic Effects

A wide variety of symptoms have been attributed to the toxic effects of fungi. Symptoms, such as fatigue, nausea, and headaches, and respiratory and eye irritation have been reported. Some of the symptoms related to fungal exposure are non-specific, such as discomfort, inability to concentrate, and fatigue.
Severe illnesses such as ODTS and pulmonary hemosiderosis have also been attributed to fungal exposures.
ODTS describes the abrupt onset of fever, flu-like symptoms, and respiratory symptoms in the hours following a single, heavy exposure to dust containing organic material including fungi. It differs from HP in that it is not an immune-mediated disease and does not require repeated exposures to the same causative agent. ODTS may be caused by a variety of biological agents including common species of fungi (e.g., species of Aspergillus and Penicillium). ODTS has been documented in farm workers handling contaminated material but is also of concern to workers performing renovation work on building materials contaminated with fungi.
Some studies have suggested an association between SC and pulmonary hemorrhage/hemosiderosis in infants, generally those less than six months old. Pulmonary hemosiderosis is an uncommon condition that results from bleeding in the lungs. The cause of this condition is unknown, but may result from a combination of environmental contaminants and conditions (e.g., smoking, fungal contaminants and other bioaerosols, and water-damaged homes), and currently its association with SC is unproven.21, 22

Infectious Disease

Only a small group of fungi have been associated with infectious disease. Aspergillosis is an infectious disease that can occur in immunosuppressed persons. Health effects in this population can be severe. Several species of Aspergillus are known to cause aspergillosis. The most common is Aspergillus fumigatus. Exposure to this common mold, even to high concentrations, is unlikely to cause infection in a healthy person.

Exposure to fungi associated with bird and bat droppings (e.g., Histoplasma capsulatum and Cryptococcus neoformans) can lead to health effects, usually transient flu-like illnesses, in healthy individuals. Severe health effects are primarily encountered in immunocompromised persons.

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