​Pets produce dander  (microscopic skin flakes that they shed), and the protein in it can cause severe allergic reactions for some people.

Pet dander is a little like dandruff flakes, only smaller; at around 2-3 microns in size it easily becomes airborne and can be inhaled. ​

​Dander can cause allergic reactions for a long period and may persist for many months after the pet has left the house.  

​​The origin of the allergens is in the pet’s urine, sweat and saliva. These excretions adhere to their skin, for example when they clean themselves, and become of the dander they shed.

​Cat dander is the most commonly inhaled allergen after house dust mite and pollen. Other types of pet, such as dogs, mice and guinea pigs, may similarly cause allergic reactions.

​Because they are so light, pet allergens are widely distributed in the air, remaining airborne for several hours before settling, only to be easily stirred up into the air again.

Clearly, the best way of avoiding pet dander is to not have a pet! However, many of us love our pets too much to do without them! In that case, there are various measures you can take to reduce your exposure, including controlling the pet’s access to certain rooms, and using an effective air purifier to neutralise the dander.

​Pet allergies are known to play a role in:

• Asthma - around 40% of people with asthma are sensitive to cat allergen.
• Atopic dermatitis - characterised by a skin rash.
• Conjunctivitis - an inflammation of the linings of the eyelids.
• Rhinitis - a runny nose and sneezing.

​People with a tendency to allergy (known as atopy), should avoid owning pets if possible. Unfortunately, some people who don’t initially exhibit allergic reactions, can nevertheless develop symptoms after continued exposure.

​Allergens usually enter the respiratory system through the nose. Mast cells in the airways release mediators, which trigger the allergy attack. This attack is an overreaction of the body’s immune system to the invading allergens that have bonded with antibodies. Mast cells are one of the human body’s principal defences against allergens and are found in connective tissue and mucous membranes. One of its biological functions is innate immunity including involvement in host defence mechanisms against parasitic infestations, tissue repair, etc.

​​Pet dander is very ‘sticky’ and can stay in your hair, clothes and other belongings for long periods of time. This is why you can still suffer symptoms when you are away from the pet causing those symptoms.

The major cat related allergens are found in the cat’s sweat and saliva and the major dog related allergen is found in its saliva.

Perhaps the best pets for a pet allergy sufferer are fish, as they are not associated with allergy!

​Before turning to technological or other solutions, careful allergen avoidance / environmental allergen control is important. For example:

• Do not let your pet roam the entire house, as it will shed allergen-containing dander wherever it goes, and that dander persists for months, both in the air and on the surfaces it sticks to.
• Never allow your pet to enter the bedroom of an allergic person. The worst thing you can do is to allow the animal onto the bed itself.
• If practicable, confine your pet to an outdoors dry and comfortable shelter, or to just one well-ventilated room. This gives the person who suffers with the allergy the best chance of controlling their symptoms. If your pet is to be allowed controlled access to the house, the kitchen, with its lack of soft furnishings, is a good choice.
• If possible, and if you spot it in time, put a cat outdoors as soon as it starts washing itself because this is when allergen starts to spread.
• Reduce dander spreading by washing your pet regularly with an allergen shedding control shampoo, such as PET+, which claims to reduce allergen load by more than 85%.
• Cuddling your pet is part of the fun of ownership, and it is therapeutic for both of you, but be sure to thoroughly wash your hands afterwards, otherwise you will in turn quickly spread any dander on your hands to surfaces and the surrounding air. Similarly, don’t touch your face if your hands have dander on them as it will quickly reach your eyes and lungs.
• If your dog has hair that moults, ask someone to brush its coat regularly outside to remove excess hair and prevent it moulting in the house.
• Your carpets, curtains and soft furnishings become a reservoir of pet dander wherever your pet has been. So be sure to vacuum regularly with a vacuum that collects dander efficiently and doesn’t leak it back into the atmosphere, and damp dust daily (rather than using a dry duster).
• If practical, consider reducing soft furnishings and carpets.

While numerous manufacturers of ‘air cleaners’ / ‘air filters’ claim to be able to clear pet dander from the air, they can only reduce, not eliminate, the problem, because:

• they can only clean the air that passes through them, and some air in the room never passes through the filter
• they don’t clean surfaces at all and it only takes a small disturbance to put settled dander back into the air

​House dust mites are one of the most potent and common domestic and workplace triggers of allergic reactions. 

​​Dust mites are microscopic eight-legged creatures called arachnids and they are closely related to the spider and the tick. They are found in every home and their presence is not an indication of poor cleaning!

​It is not the dust mite itself which is the allergen but enzymes (proteins) found in its droppings and decaying body. The whole droppings themselves are particles between 4 and 20 microns in size but may crumble into particles as small as 0.5 microns across.

​House dust mites feed upon the skin scales naturally shed by humans and other animals which are found in house dust. Although their presence is harmful to people who become allergic to them, dust mites do not bite or spread diseases.

While usual household insecticides have no effect on dust mites, fortunately there are multiple ways to reduce exposure to dust mite allergens in your home.

​As with other allergens, dust mite allergens cause an ‘over-reaction’ of the immune system in an allergic person. In allergy sufferers Immunoglobulin E (IgE) antibodies present on the surface of mast cells trigger the release of histamine when allergens stick to these IgE antibodies. It is histamine that produces the characteristic symptoms of an allergic reaction. 

​​To survive, house dust mites absorb water from the air. When humidity is less than 50% they tend to dry out and die. They also prefer temperatures around 21°C (70°F).

It is thus crucial to get rid of damp in your home. Ventilate by opening windows, and check for condensation in the kitchen and bathrooms. If you live in a humid area, consider buying a dehumidifier but remember that very dry air can be uncomfortable especially if you suffer with sinus or respiratory conditions. 

​The fight is never ending - dust mites are everywhere and even if you can get rid of all of them in your home, new ones would still appear (they are carried into your home on people’s clothing, for instance). So, look for long-term solutions which will reduce your house dust mite burden.

​These measures will create an environment that could seriously reduce the house dust mite burden in your home.

When choosing allergy cleaning products, be careful to use cleaning products with natural ingredients. Spraying a chemical, especially on a regular basis, can be a severe trigger for people suffering with allergies.

​Cockroaches are commonly found in crowded cities and in, for example, the southern United States. Certain proteins in cockroach feces and saliva also can be found in house dust. These proteins can cause allergic reactions or trigger asthma symptoms in some people, especially children. Cockroach allergens likely play a significant role in causing asthma in many inner-city populations.

​While numerous manufacturers of ‘air cleaners’ / ‘air filters’ claim to be able to clear dust mite allergens from the air, they can only reduce, not eliminate, the problem, because:

​You can learn more about why traditional air cleaners don’t work well here and why Airora’s unique technology does work here.

​​Mould spores are a potent allergen that can trigger severe asthma and rhinitis symptoms and cause a broad range of respiratory conditions. It occurs both indoors and outdoors and the density of mould spores is normally much higher than that of Pollen.

​Mould spores, sometimes also called fungal spores, are light and are therefore readily carried through the air of your home or office. This is because their diameter is between one and 100 microns, depending on species, with most being between 2 and 10 microns. Moulds come in a variety of colours: white, grey, orange, green, pink and black.

Your first step in keeping the mould count under control is to ensure that you tackle any damp areas. Another important step is to neutralise mould spores in the air and on surfaces, to prevent the mould from spreading.

​In a small number of people, symptoms of mould allergy may be brought on or worsened by eating certain foods such as cheeses processed with fungi. Occasionally, mushrooms, dried fruits, and foods containing yeast, soy sauce, or vinegar will produce allergy symptoms.

Common symptoms:

• trigger severe asthma attacks
• sore eyes, nose and throat irritation
• coughing
• wheezing
• impaired lung functioning

​Mould spores can also cause Allergic Bronchopulmonary Aspergillosis (ABPA) which is an allergy to the spores of Aspergillus fumigatus. Around 5% of adults with asthma develop ABPA at some time during their lives.

Mould loves damp conditions, so you will tend to find it in places such as:

• kitchens
• bathrooms, especially on tiles and shower curtains
• in rooms with lots of houseplants, because mould can live on the soil
• cellars and basements where ventilation is limited
• any unheated room
• old houses

Keep your home or office well-ventilated and dry, and discourage the dispersal of mould spores:

• when you are cooking, close the kitchen door and open a window
• dry clothes outside wherever possible
• don't have a carpet in your bathroom
• dust and vacuum regularly
• check the shower head very regularly and keep it clean
• replace any shower curtain regularly
• remove any old furniture that smells of mildew
• never sleep in a room with visible mould
• real christmas trees have mould growing on their needles and release spores in the warmth so use an artificial tree instead
• don't leave decaying food and fruit around
• food kept in plastic bags is more prone to develop mould so always remove from the bag to store
• always clean work surfaces of any food debris
• avoid handling old clothes and old books; especially if you can actually smell the mildew
• wash the bottom of your kitchen rubbish bin regularly
• check inside and under the freezer and fridge, especially in the rubber door seals where black mould can collect
• be aware that building works, and household cleaning, can stir up mould spores, so keep away at these times if you are allergic
• consider using a powerful dehumidifier or air-conditioning unit to remove moisture from the air and dry out the building fabric

Repairs & Maintenance:

• deal with any cracks, leaks, or rising damp
• check out any possible leakage, for example from a washing machine, which might be contributing to the damp
• deal with clogged guttering which could otherwise lead to water overflow running down outside walls and penetrating indoors

​A mixture of bleach and water, a mixture of white spirit and surgical spirit, or a specialised anti-fungal spray can be used to get rid of mould patches. Mould tends to reoccur, so you may well have to repeat your cleaning operations.

​While numerous manufacturers of ‘air cleaners’ / ‘air filters’ claim to be able to clear mould spores from the air, they can only reduce, not eliminate, the problem, because:

• they can only clean the air that passes through them, and stratification, eddies and more means that some air in the room never passes through the filter
• they don’t clean surfaces at all and it only takes a small disturbance to put settled mould spores back into the air

On a warm day, when there is naturally a lot more pollen around, warm air rises up from ground level, taking pollen up with it. When the air cools, after dusk, the pollen that has risen during the day drifts back towards the ground. This effect creates what is sometimes termed a 'pollen shower' and explains why, in the middle of a hot night, you may get an allergic attack when you are in bed, particularly if you have the bedroom windows open. ​