Desensitisation – an alternative treatment – by Dr Damien Downing

Described by Dr Damien Downing MBBS, MSB, President, British Society for Ecological Medicine.

Over the past 30 years we have been living through an epidemic of allergies and autoimmune diseases (and cancers). Our genes cannot have changed enough to account for this; the one thing that could explain all three and which has changed dramatically is our environment; levels of environmental pollution only go up, never down. By the time there is sufficient evidence against an individual pollutant, it is too late for so many people. The current obvious example is bisphenol a, which is very harmful to infants.

How visionary of Amelia Nathan-Hill to set up Action Against Allergy in 1978! I think the Clinical Ecology Group was established the next year, soon after that becoming the British Society for Allergy and Environmental Medicine. I came into the field in 1980, and in 1983 we set up the British Society for Nutritional Medicine. The two societies merged 10 years later to become the British Society for Ecological Medicine, because it had become impossible to separate the strands of allergy, nutrition and toxicity. Dr Stephen Davies coined the phrase, and wrote about, the Nutrient-Toxin Interface; the more pollutants we have to deal with, the more nutrients we use up in doing so.

That’s how we address adverse reactions these days, in what I hope is an integrated, holistic manner. Logically the first step has to be avoiding exposure. As the old saying goes, when you realise you’re in a hole the first thing to do is stop digging. Sometimes of course it takes a certain amount of logic and/or experimentation to work out what needs to be avoided, and sometimes it’s in the internal environment already, and has to be removed. I had a run–in with nickel last year myself (it’s no bad thing for doctors to have a taste of their own medicine now and then).

Sometimes, though, we cannot change either the external or the internal environment enough to make a real difference to the allergy, and then we turn to desensitisation.

If a vaccine is a small injection of something that persuades your body to react to it, a desensitisation is a small dose that stops or reduces your reaction to something. The difference is in firstly the size of the dose, and secondly in what else you put in the injection. Almost all vaccines have adjuvants in them – small doses of substances such as aluminium or mercury or sodium borate which intentionally irritate the immune system and cause it to react, both to them and to the organism. The desensitising shots that we use only contain naturally occurring enzymes such as beta-glucuronidase, and small molecules such as zinc-protamine, at doses designed to “talk down” the body’s exaggerated immune response.

Many years ago when I was a GP we used to do “incremental” desensitisation for hay fever, bee sting reactions etc. The theory was that by starting with a very small dose of the allergen and increasing it over a period of weeks, the body would accept it and leave it alone. It worked sometimes, but there were a handful of deaths reported too, so it was banned in the 1980s. Now a few allergists are doing it again, but only in hospital with every precaution, and emergency measures standing by. I wouldn’t advise it myself. EPD was never subject to any such restriction because there was never a death, or even a severe reaction, associated with it.

The beginning
Beta-glucuronidase is what started the whole McEwen story off; in 1959 a Czech doctor working in London found that injecting another enzyme, hyaluronidase, into the nose (ouch!) sometimes alleviated sneezing. Dr Len McEwen, then a junior researcher at St Mary’s Hospital in Paddington, showed that it was beta-glucuronidase, a contaminant of the hyaluronidase, that did this. He went on to research the effect in depth, and in 1978 produced the first-ever batch of Enzyme-Potentiated Desensitisation (the enzyme being beta-glucuronidase).

Over the years there have been a number of papers showing that EPD works in hay fever and asthma, reducing both severity and duration of symptoms in 9/10 studies; two from Great Ormond Street showing benefit in ADHD and childhood migraine; and one in ulcerative colitis showing benefit in the second year of treatment. A 1984 study looked at safety, and found that EPD for hayfever was exactly as effective as conventional desensitisation, with a fraction of the side-effect rate and in fact no severe reactions at all. This certainly meshes with experience; in 30 years of using EPD I have always had adrenaline and the other emergency medications to hand, but I never once used them. I did draw up the adrenaline ready to use it on one occasion, but in the end did not need it.

McEwen also spent 30 years refining the adjunctive treatments – nutritional supplements, medications, dietary changes etc – that help EPD to work even better, and generally speaking we have tended to advise patients that the probability of them receiving benefit from it is at least 80%.

For some years there was a thriving EPD Society in the USA, with over 200 doctors using the treatment. The president of this was Dr Butch Shrader, and they did a considerable amount of audit on the treatment before the FDA, the American regulators, closed them down abruptly. Then in 2011 it was announced that the McEwen Laboratory in the UK had to close at short notice due mainly to regulatory issues here. However some European EPD users rose to the challenge, and EPD is now manufactured in Portugal under an existing EU licence. There are some limitations to this treatment, and I chose to go with the alternative, known as LDA (Low Dose Allergotherapy) manufactured by Dr Shrader following the problems in America. The design and build are very similar to EPD, although a few extra allergens have been added in. The response is similar too, at least on average, although there is quite a spread; in other words, some people do distinctly better on LDA, some distinctly better on EPD. Unfortunately we can’t predict which way this will go, at least not so far.

Injection at intervals
So what is the experience of having EPD (or LDA) treatment? You will receive a very small injection into the skin of the underside of your forearm, sometimes one on each arm, and this will happen every few weeks or months. Normally we start with a two or three month interval, and extend it slowly from there. The injections stings rather than really hurting (for children we can rub an ice cube on beforehand). You will usually get a swelling, something like an insect bite, somewhere from minutes after to 24 hours after the shot.

Because the injection contains a very very small dose of a number of allergens, if you are exposed to something that you react to, at around the time of the shot, it can greatly alter the dose and stop the response. Therefore, firstly, it is difficult to treat you in high pollen season if you suffer from seasonal rhinitis, for example, and if we are treating you for reactions to foods you need to go on to a rather restrictive diet, just for about 72 hours.

Even so, your reactions may get worse during the first couple of weeks, and you may feel generally not so well. After that the benefit should kick in. What we aim for is that the initial reaction will stay the same with each dose, more or less, and the subsequent benefit will increase in both degree and duration.

According to the textbook (the big manual for doctors written by Dr McEwen some years ago) people who only have seasonal rhinitis, a.k.a. hayfever, should have two shots per year for three years, before the season starts, and then stop, and will never need to come back for a booster. It does happen, but nobody is really a textbook case. Some choose to have a single booster every year for years on end, reasoning that they don’t want to find out the hard way that it has stopped working in the middle of the season.

People having treatment for food intolerances usually settle on about four shots a year for the first few years, and then gradually extend the interval. We try to time it so that the last shot is just starting to wear off when you have your next, so that you know where you stand; otherwise, who knows, it might have gone on for much longer. Eventually, usually, it does, and people stop coming, or come back after an interval of two or three years saying “I was fine until two weeks ago”.

Chemical sensitivities are, as you might have guessed, at the next gaming level. It is unusual for them to develop in somebody who is not already allergic/intolerant, and they represent a progression of the disease. They can also be extremely hard to avoid in everyday life. We ask everybody attending our clinic not to wear perfume or make up, but it is often their accompanying friend who doesn’t realise that her scarf is still steeped in perfume, and ends up having to sit in the car!

McEwen clarified a point that is carefully ignored by a lot of researchers who seek to debunk the very idea of chemical sensitivities; that it is airborne chemical fumes which can cause such devastating reactions, because they can be absorbed directly through the nasal mucosa, and can be within the brain in seconds. Of course you could argue that although chemical sensitivities sufferers are the “pit canaries” they are also the lucky ones, because these early warning symptoms help them avoid absorbing quantities of the chemicals into their system where they can wreak long term havoc. Desensitisation can certainly help with chemical sensitivities, but I do not think it can switch them off completely, and if your allergies are that bad then you certainly ought to be using other treatments as well – anything that helps, in fact.

I am often ask whether desensitisation can help with electro-sensitivities, and I think the honest answer is “a bit”. There is nothing we can add to the injections that addresses this problem specifically, but regular injections do dampen down the immune system’s overall level of reactivity, which helps with all reactions. After all, John McLaren Howard’s experiments showed that applying an everyday sort of “electro-smog” field to blood cells in a test tube can significantly increase their level of reaction to ordinary allergens.

For more information about the British Society for Ecological Medicine visit

Editor’s note
An increasing number of enquiries about EPD have been reaching the AAA office recently, mainly due to the national attention being given to the writing of our former patron, the late Jennifer Worth. Her memoirs, the Call the Midwife trilogy, are now portrayed in the immensely popular TV series, which have in turn increased sales of her very first book, Eczema and Food Allergy – the Hidden Cause?, describing her own battle with the severe eczema she suffered in her fifties. The book includes an informative section on Enzyme Potentiated Desensitisation by Dr Helen McEwen, wife of the pioneering doctor who originated the this form of treatment. AAA can provide members with the contact details of their nearest EPD/LDA practitioner. Jennifer’s book on eczema is available for £7.50, post free, from Merton Books, PO Box 279, Twickenham TW1 4XQ or telephone 020 8892 4949.

This article was first published in Allergy Newsletter No.107, Spring 2013.