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What is an Allergy?

by Dr DF Smallbone(more info)

listed in allergies, originally published in issue 15 - October 1996

In the standard dictionaries of pre-1950, the word "allergy" does not appear. For instance, in Ward & Locke's Standard Etymological Dictionary of 1947, the word "allergy" has no entry although it had become a standard medical term. According to the standard teaching medical textbook – Davidson's Principles and Practice of Medicine – which I was taught from in the late 1950s, the word "allergy" was coined by a German, von Pirquet. He derived the word from two Greek words – allos (meaning 'other') and ergon (meaning 'action') to denote 'the alterations in degree of skin sensitivity to tuberculin which he observed during the various phases of the tubercular infection'.

A very specific meaning!

Medically, by 1960, the meaning had lost this specificity but had developed an equally specific meaning. It meant a group of disorders which had their origin in a hypersensitivity to contact with certain erogenous protein substances. There was a clear line of distinction between allergy and hypersensitivity reactions to other materials.

This definition has remained the basis of the use of the word "allergy" although most medical spheres have realised that allergies do develop to other than proteinaceous material such as long chain polysaccharides. There is still a group of diseases that are thought of as distinct entities and are related to hypersensitivity reactions of the body. More recently these latter have become accepted as forms of auto-immune diseases which have a more complex derivation than simple allergies.

This leaves us with three apparent medically distinct, although related, groups of conditions.

ALLERGIES specific hypersensitivity reactions that the body produces to contact with various chemical structures, mainly of protein and polysaccharide nature.

HYPERSENSITIVITY REACTIONS which are generally fairly non-specific reactions that the body produces when confronted with materials it, temporarily or permanently has no ability to deal with. They are mainly related to food groups. These are also correctly called INTOLERANCES.

AUTO-IMMUNE DISEASES are complex induced hypersensitivity reactions which the body inadvertently has produced as a result of altered states of body defence mechanisms or changed immune system response activities.

As we have said, these three events are very inter-related but have different pathways of initiation, at least as far as our present knowledge leads us to believe. There may be other sub-divisions of these three hypersensitivity reactions that we have to accept as our understanding enlarges.

This division of pathways leads us to expect that the three various types will show up and respond differently to each other. This, indeed, seems to be the case.

The Differences and Similarities

Let us look at the three basic types. Firstly, let us take the true Allergy.


A true allergy reaction is a body response to a specific allergen, some basic chemical structure to which the body's reactive processes are triggered. This is usually a long chain protein molecule or polysaccharide, or part thereof. Its original function appears to be to prevent material that is "foreign" to that body from being accepted by that body thus providing an early warning system of invasion. Unfortunately, if, as so often happens, the body 'shortcuts' the process by reacting to and registering only part of the molecule as the invader, any time that particular chemical configuration is encountered the body will react as though the whole structure were present. Thus we find the original allergen becomes not the only originator of the allergic reaction but any material that has that same partial chemical structure will also produce the reaction. We have now developed a whole string of allergic reactions to more than just the original "invader" but all having an identical chemical structure as part of its formula.

The initial protective response has become out-of-hand. The only real answer to the problem is, in some way, to desensitise the body – reduce the defence reaction to a minimal response.

Generally once an allergy has been established, the response will always occur to that chemical structure. Given sufficient passage of time without recurrent contact with the allergen and the reaction will gradually diminish. The body response can also, often, be taught not to react.

A true allergic reaction is ALWAYS accompanied by histamine release and depending on the nature of the allergen, usually shows some evidence of other immune system responses, such as an eosinophilia (increase over normal of the white blood cells called eosinophils). The reaction may manifest in any tissue and, therefore, the symptom picture is less dependent on the allergen, than the tissues of the body which manifest the reaction.

Auto-immune Diseases

This is a most serious development. It is now recognised that many disease processes may be categorised as Auto-immune Disease processes. It is even thought that Type I 'Juvenile', early onset diabetes is probably an auto-immune disease, or at least a component of it is.

How do they develop? If the body produces an allergic response to an allergen and goes on to react to part of the chemical structure of that allergen, then, whenever that structure is met within the body, it is recognised as "alien" and will be reacted against. That chemical format that is recognised in this way is called a Hapten. In some instances the hapten may be quite a simple structure. The simpler the hapten is the more likelihood there is of that same chemical structure being present quite naturally as some part of that body. If recognised as such the body's own defences will be brought to bare on part of its own chemical structure and destruction of that material, along with its associated structures, will ensue. At the same time the whole immune system will be called into action to deal with this "intruder". Either the hapten, and structures containing the hapten, will be destroyed or the immune system will become so depleted that it ceases to function efficiently thus leading to various potential disease processes taking over, either from the primary destruction of body parts or the secondary processes that can run rampant as a result of ineffective defence mechanisms. Thus is the way of auto-immune disease pictures.

Dealing with this process is much more of a problem and requires extremely prompt action in the early stages with continued support of the body defence mechanisms for a long time afterwards. Desensitisation on a massive and rapid scale must be undertaken before too much destruction has occurred and there is usually very little warning or time.

Initially there is a classical series of allergic responses with histamine release, then the disease picture of the attacked tissues develops, rapidly, and finally the symptoms of massive immune response and exhaustion take over.

Below is a list of diseases that are known as Auto-immune Diseases or have a component that is.

The Endocrine System
Hashimoto's Disease (chronic thyroiditis)
Addison's Disease (adrenal insufficiency)
Primary Hypopituitarism
Primary Hypoparathyroidism
Type I "juvenile" early onset Diabetes
Myasthenia Gravis
The Gastro-intestinal Tract
Pernicious Anaemia with Atrophic Gastritis
Ulcerative colitis
Crohn's Disease (regional ileitis)
Primary Biliary Cirrhosis
The Reproductive System Opthalmic
Orchitis with male Sterility
Ophthalmic Endophthaimitis phacoanaphylactic
Sympathetic Ophthalmia
Neurological Post-vaccinial encephalitis and post-infectious encephalitis
Guillain-Barre Syndrome (polyneuritis & neuropathy) Multiple Sclerosis
Cardiac and Renal Systems
Post-cardiotomy Syndrome
Post-infarction syndrome of Dressler
Rheumatic Fever
Goodposture's Syndrome (auto-immune glomerulonephritis)
Immune Complex Glomerulonephritis
Connective Tissue
Systemic Lupus Erythematosus (S.L.E.)
Rheumatoid Arthritis
Scleroderma Polymyositis & dermatomyositis
Salivary Glands
Sjorgren's Syndrome (kerato-conjunctivitis sicca)
Pemphigus Vulgaris
Bullous Pemphigoid
Karposi's Sarcoma
Acquired Haemolytic Anaemia
Idiopathic Thrombocytopenic Purpura
Immune System
Acquired Immune Deficiency Syndrome

This list is rapidly growing in size as we begin to understand the mechanisms of modern diseases.

Hypersensitivity Responses (Intolerance)

The vast majority of the so-called "allergies" fall into this category. They are not life-threatening as true allergies and the auto-immune diseases often are, but produce states of below normal health. They usually manifest somewhere within the gastro-intestinal tract as most of them are food related and this is where the first body contact is made – remember the inside of the gut is still the outside world. Until materials pass through the gut wall, they have not entered the body. The gut cells, therefore, are a good place to have our first line of defence.

Unlike true allergies the body response is taking place on its surface. There is no histamine release involved and the immune responses that the body produces are rather nebulous and nonspecific. Most commonly the symptoms are of some form of gastro-intestinal irritation or poor digestive processes. The body's main aim is to remove the irritant as rapidly as possible and hence the most common problem is the production of intestinal hurry and its attendant symptom picture of diarrhoea (or loose stools), much intestinal noise and activity, fermentation and gas production instead of digestion and poor absorption of nutrients. Obviously, if this is allowed to continue it will, eventually, have serious effects upon the body.

These intolerances often occur in people who are already below par for a variety of reasons and so often accompany a true allergy or other disease's manifestation. This close association with other disease states often is mistakenly taken as a disease picture itself. Indeed, it is very difficult to sort out which set of symptoms belong to the disease manifestation and which to the hypersensitivity reaction.

So, what are we left with as far as differention is concerned?

The table below (not shown) gives some idea of the similarities and differences in summary form.

What Value Allergy Testing?

This to some extent depends on what is meant by "allergy testing". If we mean presenting to the body by whatever means we can a material that is thought to be an allergen, this depends on two factors.

* Is it a true allergen?
* Where and how is it presented?

A true allergen will produce an allergic reaction in an allergic person. This can be verified by the presence of a local reaction and the production of a histamine response. (Histamine is generated from the reaction of Immunoglobulin E [IgE] with an antigen, from the amino-acid Histidine, in the presence of pyridoxal 5-phosphate.)

This response will always be repeatable with the same allergen in the same person, provided a very long time has not elapsed.

The rapidity or severity of the response will depend on the method of application. Surface application will be less dramatic than injection under the skin and intravenous injection may very well prove fatal. Sometimes surface application will not produce a response, depending on the state of the immune system and the degree of "responsivity" of the individual at that time. Sub-dermal injection will always produce some reaction.

In the case of Intolerances, whatever the method of application, the reaction can be variable. Sometimes quite a strong reaction occurring, sometimes none, irrespective of the site and mode of application.

This is often the simplest way of determining whether one is dealing with a true allergy or an intolerance. If the reaction to the "allergen" is persistent and repeatable, after some time has elapsed, then it almost certainly is a true allergy. If the response is variable and different "allergens" produce a reaction and the "allergen" seems to change each time, then this is probably not a true allergy, but is an intolerance and an indication that the immune system is flagging and needs some support.

I am, currently, not aware of any form of testing technique that can be relied upon to produce regular and reproducible results unless a true allergy is the cause.

How does this help us to decide on appropriate treatment?

Firstly, if we repeatedly produce different reactions over a period of time and keep coming up with various "allergies", we can be pretty certain we are dealing with an intolerance. If it is early on and very variable, minor changes to diet, a good look at potentially immune system-draining states made and corrected and support for the immune system given, then the only other two ingredients required are a little time and a little patience. Patient compliance is essential.

If, on the other hand, we find a persistent, repeatable reaction to an apparent allergen that is consistent over time, this probably means we are dealing with a true allergy. The management requirements are somewhat different. Firstly we have an immune system that is capable of overstimulation (not yet in trouble) and so we do not want to add to this hyper-excitability. We need to find techniques that calm the immune system, not inflame it. This can vary from person to person. It invariably means minimising the contact with the allergen for long enough for the response to diminish. We should preferably find some means of desensitising that individual's immune system. This can be accomplished through orthodox approaches or such treatment forms as homoeopathy, acupuncture, aromatherapy, etc. It may be essential to use some form of histamine-release suppression in the acute phase, until control has been established. It is important to find a control technique in order to prevent exhaustion of the immune system from persistent overstimulation.

It is also important to allay the allergic person's over-responsive immune system before they develop their hapten response, previously mentioned, and run the risk of potentially going on to produce an auto-immune disease state, although not all these are consequent upon an over-reactive immune system. This is another story for another time.

In Conclusion

It is important to establish whether a person is suffering from a true allergy or merely an intolerance, because part of the necessary treatment is different and associated conditions will be different and require different approaches.

It also matters little what technique is used to determine the allergen. The importance is in the interpretation and, in true allergies, a reaction will only be produced if the allergenic material is physically presented to the body, whilst it is in a reactive state.


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About Dr DF Smallbone

Dr David Smallbone M.B., CH.B., L.R.C.P., M.R.C.S., M.F.Hom., F.C.O.H. Senior Medical Advisor and Senior Lecturer in Medical Sciences to the College of Natural Nutrition.

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