The Allergy Threshold, Companion Animals and Me!

The term allergy threshold is often mentioned when talking about allergies in both humans and animals but what does it actually mean?

One analogy that’s been used to help explain it is the humble bucket. When there is too much water in the bucket, it spills over and that makes a mess. Nobody is worried when the bucket is half full because it doesn’t cause anyone a problem. Likewise when your allergy burden gets too high you tip over the allergy threshold and then see the signs associated with allergy for example itching, scratching or sneezing.

We used to think one allergen, be that a pollen or dust mites for example, was responsible for ‘filling the bucket’. More recently it has become apparent it is far more likely several different allergens, whether they are in our food or from the environment, each contribute to getting you closer to that threshold or point of overflow. For this reason it’s really important to try and control multiple aspects of allergic diseases. The less that goes into the bucket day to day, the more leeway you have if you suddenly get a downpour!

It is suggested that 10-15% of dogs in the UK are affected by allergic disease, and it is being recognised with increasing frequency in cats.

Although I have been mildly allergic to various things throughout my life I hadn’t considered this concept until starting work at Avacta Animal Health. But shortly after starting I experienced my personal ‘real life’ example.

The allergy threshold concept works as follows:


In this dog only environmental allergens are present and these are above the allergic threshold so clinical signs are seen. If completely controlled the clinical signs should resolve. The same would apply if food allergens were present in isolation and above the threshold.


The combined allergic stimulation from the environmental and food is below the threshold so no clinical signs are seen. In this case if any intermittent compounding factors such as ectoparasites or seasonal pollens were added, the allergenic stimulation could easily then go above the threshold and cause clinical signs.

The combined allergenic stimulation is above the threshold so clinical signs are seen. Clinical signs could be managed by either controlling dietary or environmental allergens but by only considering one aspect the pet is left close to the threshold and therefore vulnerable to compounding factors.


The allergenic stimulation is above the threshold so clinical signs are seen. It is not only in combination that this will occur as both environmental and food allergens individually are above the threshold. Even if one component is completely controlled there may not be a reduction in clinical signs. Both must be identified and controlled for resolution.

My ‘real life’ example:

I have had mild hay fever since I was a child, but nothing more irritating that a mild cough and a runny nose. I have also always been allergic to dogs and cats, but again nothing more than a slight itchiness and the odd sneeze whilst in their presence.

But last summer my then 9 year old daughter played the ‘only child card’ and said that because she didn’t have any brothers and sisters then she neeeeeeded to have a pet. We went through the various options and decided a cat would be the most sensible choice given our current circumstances, and being the fabulous father that I am I agreed even though the beast may cause me some discomfort. For the first 6 months my life didn’t change much (however, initially my wife and daughter were so terrified of a kitten tearing around the house and would lock themselves in their bedrooms!), but when spring came along everything changed.

The clinical signs of allergy manifest themselves in many different ways from dermatological signs, such as itching or repeated skin infections, through to gastrointestinal signs (diarrhoea, vomiting, weight loss). This is dependent on the allergens involved and individual response, but for me it was mainly respiratory.

I started getting breathless after going for a run, which I put down to hay fever, but eventually I started finding it difficult to breath even when I was just sitting in the living room (and not just when I was watching Game of Thrones!).

I believe the combination of pollen and cat dander had tipped me over the edge i.e. I had reached my threshold.

I went to see the doctor and he gave me an inhaler to use just before exercise or when I was having a particularly difficult time breathing. I used it for a couple of weeks, but once the pollen levels subsided the wheezing stopped. The cat dander is still there, but on its own it’s not enough to cause any major symptoms.

So that’s my experience of the allergy threshold. If you have any examples, either human or animal relates, then you can share them with us at If we get a few we will share them in a future blog.

Written by Gary Skipper – Marketing Manager


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