Many people with asthma or rhinitis have simple allergy to dust, house dust mites, pets or moulds. Skin tests, though far from perfect, often succeed in identifying specific triggers.

Dust mites thrive in a warm, humid environment such as modern, well insulated, centrally heated homes; their main habitat is bed mattresses, carpets and soft furnishings. We know that they die in very low or very high temperatures and where the humidity is low. Cooler, well ventilated homes discourage inhalant allergies.

Some patients, through the years, made the observation that their asthma, previously thought to be a permanent or irreversible' problem, actually clears within 48 hours of arriving in any Mediterranean country, (often attributed to the sea air') or high in the mountains (where humidity is low), only to relapse on their return to UK.

Atopic eczema goes through similar but more delayed changes. This confirms that many of these problems can, partly or totally, be reversed, if we could effectively control the quality of the air we breathe.

There is evidence that small changes in the domestic environment can make a significant difference: an air-filter in the bedroom, an anti-mite mattress cover, thoroughly ventilated bedrooms, bare floors and a vacuum cleaner with an efficient air-filter.

The benefits are best noticed in children, whose allergies are simpler; adults often have more serious problems, which require specific preventative treatment such as desensitisation. Families with a history of allergies should consider using simple air-purification measures as a prevention, rather than wait until their children develop any of these conditions.

Asthma, Eczema, Rhinitis & diet Contrary to popular belief, rhinitis and asthma are not always caused by allergens in the air. Some patients find that their symptoms get worse after eating certain common foods and get better when they leave them out of their diet for one to two weeks.

On the basis of this observation we use a process of elimination and challenge, which helps to identify specific foods, responsible for any breathing problems. This kind of allergy is very different to peanut allergy, which is fast and potentially life threatening. It is a delayed (masked') allergy and is a common cause of breathing problems, characterised by congestion and/or mucous production from the sinuses, nose, throat or the bronchi.

Dairy products are on top of the list for causing mucous secretions, Nasal polyps are frequently caused by inhalant allergy combined with food intolerance.

Identifying food intolerance As skin prick tests are not helpful in identifying food intolerance, our patients are often advised to follow a more varied diet. There is a good choice of safer foods to eat these days, without getting hungry.

If this is not practical because of personal circumstances, intra-cutaneous tests can be used to identify the culprits, usually some foods or food constituents: the majority of people don't react to all the parts of milk but only to casein (milk protein) and so on.

The good thing about type-B allergy is that, following avoidance of some high risk foods for a few weeks, the tolerance of the individual improves and the same items can be used again sparingly, without the same ill effects.

In our clinics, about half of patients with asthma or rhinitis or eczema have allergies to simple, natural airborne allergens.The rest have pure Type B food allergy/intolerance or a combination of food intolerance and inhalant allergy.

If all else fails desensitisation or immunotherapy is safe and effective.

Desensitisation is a method of re-educating the immune system to no longer react to specific allergens but to treat them as friendly. This is achieved by introducing tiny amounts of the very factors causing asthma or rhintis (dust, mites, animal dander, moulds or pollens).

Apart from the conventional desensitisation and immunotherapy available in a few hospitals in the UK, there are two other types of low-dose desensitisation, which are also effective and safe, both with inhaled or dietary causes.

The Enzyme Potentiated Desensitisation, which has been found to reduce levels of a marker of immediate allergy (immunoglobulin -E) and the method called Neutralisation, can switch-off' the symptoms of asthma, rhinitis or hay fever quite promptly.

Although both are unconventional', they are used by qualified doctors, specially trained in the field of allergies; they often succeed in improving or clearing your symptoms and allow a reduction or phasing out of one's medications. Both treatments are available on prescription.

In certain areas, these treatments are being funded by local Primary Care Trusts/National Health Service.

Hay fever & pollen allergies The majority of people with an allergy to pollens seem to suffer with sneezing, watery catarrh and eye irritation from late May to July/August. A small percentage of this group also suffer with seasonal asthma and require inhalers to control it.

This is a time when various grass pollens such as rapeseed (very common in Oxfordshire) Timothy and rye grass are in great concentration in the air.

A few people start having symptoms as early as February or March, if they react to tree pollen, such as birch, hazel and alder.

Many hay fever sufferers manage quite well with the help of antihistamines during the summer months. A minority with severe symptoms require desensitisation.

Cereals and flour are of the grass family and dairy products come from cows feeding on grass. Hence patients with hay fever often feel better if they reduce the use of these foods during the grass pollen season.

Dr Econs is the medical director of Oxford Allergy Centre, Bell Trees Clinic, Botley.

For further information, call 01865 200365 or 01932 820578.E-mail info@belltreesclinic.co.uk