Could You Have an Inhalant Allergy? Dr. Myhill Describes the Signs of Various Invisible Irritants, and How to Deal With Them

‘Invisible’ inhalable irritants such as dust mites, mold, danders and pollens cause a variety of physical problems. Dr. Sarah Myhill, MD – a UK-based preventive medicine and fatigue specialist – offers some basic advice on the signs of these sensitivities and how to deal with them. Excerpted with permission from Dr. Myhill’s extensive patient education website (



One can be allergic to anything under the sun, including the sun. For practical purposes, allergies are split up into allergies to foods, chemicals (includes drugs), and inhalants (pollens and micro-organisms such as bacteria, mites, etc.). Inhalant allergies usually present with problems in the airways – rhinitis, sinusitis, itchy palate and/or throat, or asthma with cough, wheeze and shortness of breath. Contact sensitivity in the eyes causes conjunctivitis and on the skin, eczema.

Diagnosis of Inhalant Allergy

This is best done by taking a careful clinical history. Reactions to inhalants are usually type I allergies – abnormal reactions to protein substances that occur naturally – which are relatively easy to test for [except for mold sensitivities, as explained below]. Blood tests can be done, as can skin tests, but these are not totally reliable.

That is because the skin reacts differently compared to the airways, which react differently compared to the gut. Furthermore, there are lots of different animal danders with different breeds – it is possible to react to one dog but not another. And people may react differently to saliva or urine. It is not uncommon for people working with laboratory animals to sensitize to rat urine.

So while the tests are a guide, clinical history is the most critical aspect.

Timing of Symptoms

Broadly speaking, symptoms worse in:

  • Winter – suggest house dust mite allergy.

  • Spring – suggest tree pollen

  • Last week of May to the first two weeks of July – suggest grass pollen

  • August to the autumn – suggest molds.


    I am increasingly finding that patients who are not responding to my standard work-up are suffering from mold sensitivity. This is not an easy diagnosis to make because tests for mold allergy are notoriously unreliable. They do not give immediate skin test reactions. Furthermore it is uncertain whether symptoms are due to allergy to molds or sensitivity to mold fumes. This is a little bit like yeast overgrowth in the gut. For some people this causes a problem because they are allergic to yeast, and for some because they react to the products of fermentation.

    In the early stages of mold allergy one often gets local symptoms such as rhinitis (runny nose with thin clear secretions and sneezing), conjunctivitis (the white of the eye may have a cobblestone appearance with redness and watering), and sore throat, but as the symptoms become more systemic they can present with foggy brain and chronic fatigue.

    Patients who come to see me usually present with the latter symptoms.

    Diagnosing Mold Allergy

    History is key here and if patients are improved in a mold free or low mold environment, then this is highly suggestive that molds are a problem.

    In order to survive, molds have to get their water from air, therefore they do not exist either:

  • In very dry climates (which may be hot dry or cold dry),

  • Above three thousand feet, where the air is too thin to hold sufficient moisture,

  • Or on sea fronts where the prevailing winds are onshore (and since molds do not live in oceans, their spores are constantly blown inland).

  • I’m Afraid You’ll Have to Go on Holiday…

    Therefore, to diagnose mold allergy I currently recommend that people have a two-week holiday in such an environment. One may have already done this and not realized that one’s improvement was actually due to mold allergy, ascribing improvement instead to other factors such as freedom from stress, or sunshine, or whatever.

    Coming Home

    Being free from molds in a temperate climate is extremely difficult. To reduce mold counts in houses:

  • Remove obvious sources, such as house plants or a damp problem.

  • Then, reduce the humidity inside the house to less than 40% using a dehumidifier and this will kill any molds living in the house.

  • Reducing the humidity is helped by trying to avoid moisture-creating activities such as drying clothes (inside), boiling pans and kettles, etc.

  • Once the atmosphere is dried up, an air filtration system helps to get rid of the molds in the air.

  • Getting the relative humidity below 40% is critically important, and one can now buy a little gadget called a hygro thermometer. [You can search for sources online] and it will tell you if you have got the humidity down to an acceptable level.


    The fundamental problem with house dust and mites is that they live on human skin scales. We constantly shed dead skin onto our clothes, carpets, soft furnishings and bed clothes, and the mites flourish on this free supply of food. Furthermore, a centrally heated home provides the perfect temperature and humidity for house dust mites to multiply.


    Getting rid of mites means attacking on several fronts:

    n The single most important aspect to tackle is humidity. House dust mites cannot survive in dry air, which is why a combination of excellent ventilation and warmth will clear them. The bedroom window should always be open for free circulation of air. Background heating will further dry bedclothes. Always draw back the bed covers in the morning so the bed can thoroughly dry (or leave the electric blanket on). On good days hang the duvet/blankets out of the windows (like the continentals do).

    n Remove as much soft furnishing as possible so that the mites have nowhere to hide and can be sucked up by the vacuum cleaner – soft toys are often the worst offenders.

    n Kill the mites by extremes of temperature (either a hot wash or pushing the blankets/duvets/pillows into the deep freeze).

    The House

    n Windows open.

    n Avoid carpets – go for wood, linoleum, stone or tile floors. Do not have too much furniture (which accumulates dust).

    n If you can afford it, consider buying [a vacuum cleaner that filters out dust and mites. You can search for these online.]

    n Keep pets out of the house.

    n Keep wet out – dry clothes outside if possible, cook with the window open to let steam out, air the bathroom thoroughly after use.

    The Bedroom

    This is the main difficulty because we spend almost a third of our lives in a warm bed – ideal for breeding dust mites. However, it does take a while for the population of mites to build up, and this is the key to keeping numbers down.

    n Bedding – Have two sets which you alternate between. Use a hot wash to kill the mites in bedding, then either hang out to dry on a windy day to blow away the debris, or use a tumble drier to blow the dead particles away.

    n Pillows, duvets and blankets – can be put into the deep freeze to kill the mites, then hung out to air, or put through the tumble drier. Each night put a fresh clean towel over your pillow to reduce inhalation of mites.

    n Mattresses – are a problem. Ideally these should be covered with plastic to stop mites penetrating them. To prevent sweating put a blanket on top (which is treated in the same way as bedding above).

    n Dust-mite-proof bedding – [A number of products in cotton and other fibers that claim to be mite-proof are available and can be searched online. Until recently it was believed that feather or down pillows harbored more dust mites, but recent studies show they perform better in this regard than synthetic pillows. One theory is that the casing of feather pillows can offer a more effective barrier.]

    n Soft toys – Put through the wash, or if this causes offense, into the deep freeze when the owners are at school.


    The classic example of inhalant allergy is hay fever [associated with pollens] –

    n This may cause itchy conjunctivitis (the white of the eye may have a cobblestone appearance), with redness and watering.

    n In the nose there is rhinitis with thin clear secretions and sneezing.

    n There may also be blockage and loss of the sense of smell with sinusitis.

    n Pollen in the nose, mouth and throat may cause itching.

    n In the lungs, asthma.

    These effects are all mediated by the release of histamine. Conventional treatment of hay fever is about symptom suppression with:

  • Antihistamines (block the effect of histamine),

  • Sodium cromoglycate (stabilizes the allergy cells)

  • And steroid sprays or tablets (these turn off all immune reactions, good and bad).


    This is about avoidance and desensitization.

    Avoidance. This is most important for house dust mite sensitivity. [As discussed above.] A dry climate often brings relief from house dust mite and mold sensitivity.

    Desensitization. My preference is to desensitize, and I use enzyme potentiated desensitization (EPD). This has been proven in many trials to be effective in treating hay fever. See “Enzyme Potentiated Desensitization – How it works.” [Note: EPD involves injections using low doses of antigens “potentiated” by the enzyme beta glucuronidase. It is available in different “mixes” used to desensitize against a variety of inhalants such as pollens, molds, pet danders, mites, perfumes, and more. Currently, EPD is available in the UK and Canada, but not in the U.S., where an American-made injection called LDA (Low Dose Allergens) formulated by a compounding pharmacy may be prescribed, according to Dr. WA Schrader, MD, at the Santa Fe Center for Allergy & Environmental Medicine]

    Only one EPD injection is needed before the hay fever season starts (no later than May 1st), and because EPD is in the homeopathic range there are virtually no side effects.

    Neutralization. Neutralization also works well. (For details, go to Ideally, the concentration of vaccine should be worked out before the season begins, but neutralization can be used to turn off symptoms during the season. In this respect it is superior to EPD. For allergies which are perennial, I also use EPD, but injections need to be given regularly – the gap between injections runs: 6-8 weeks; 2 months; 2 months; 3 months; 3 months; 4 months; then play it by ear. [Note that neutralization or ‘desensitization’ appears to be based on homeopathic theory. As Dr. Myhill explains, she is happy to use an ‘alternative’ method in combination with conventional medicine, if she has found it effective and safe.]

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    To read more of Dr. Myhill’s articles on various types of allergies, chemical sensitivity, autoimmune disorders, and more, go to


    * This material is reproduced with permission from Dr. Sarah Myhill’s patient-information website ( R Sarah Myhill Limited, Registered in England and Wales: Reg. No. 4545198.

    Note: This information has not been evaluated by the FDA. It is generic and is not meant to prevent, diagnose, treat, ameliorate or cure any illness, condition, or disease. It is essential that you make no decision about additions to or changes in your healthcare plan or health support regimen without first researching and discussing it in collaboration with your professional healthcare team.

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