Aller­gies: diagno­sis, treat­ment and preven­tion

How can allergies be diagnosed?

It takes a lot of detective work to identify the allergen that triggers the patient's symptoms from among all the possible culprits. There is no one test that can diagnose allergies; they can only be diagnosed using a combination of four different methods.

Medical history

The patient's history of allergic symptoms (at home and at work) can provide valuable information and must be taken before any allergy tests are performed.

Skin tests

Skin tests (prick, epicutaneous, intracutaneous, scratch or patch tests) involve the application of possible allergens to the skin, which is then observed to see whether an allergic reaction occurs (a pustule or welt). The patient should avoid or stop taking antihistamines (anti-allergic medication) some five days before the skin test in order to avoid getting false results. Cooking salt is used for negative control tests and histamine for positive.

Laboratory tests (blood tests)

Blood samples are tested in the lab to determine reactivity and sensitisation to specific allergens. Allergic reactions cause a rise in the level of specific IgE antibodies in the blood.

Follow-up history and provocation test

A follow-up history is then taken to help interpret the test results (was the patient actually exposed to the allergen? Do the symptoms and the test results match?)  During the provocation test, the clinical symptom (e.g. conjunctivitis, allergic rhinitis, skin rash) is reproduced by recreating "natural conditions". If the patient is allergic to dust mites, for example, the reaction is provoked nasally, i.e. the allergen is placed in the nose.

Which treatment is the right one?

Avoiding the allergen

The first step towards preventing allergic reactions is to avoid the trigger (abstention). Depending on the type of allergen, this may involve eliminating a food, cleaning the house thoroughly in the case of a dust mite allergy, or switching to a different skin cream.  However, avoidance is impossible if the allergens are universally present. People with pollen allergies, for example, are not always able to go out of the way of their trigger. The best treatment in such cases is hyposensitisation.

Hyposensitisation

Hyposensitisation, also known as desensitisation, is a causal treatment which involves administering gradually increasing doses of the patient's current allergen to make him/her insensitive to it.

Medication

Treatment with medication helps prevent and alleviate allergy symptoms. It is often the only way in which the patient can get through the day without symptoms or with only minor ones. Medication may be topical or systemic depending on the active substance. Topical medication includes eye drops, nasal spray, creams and asthma spray. It only works on the part of the body to which it is applied. Systemic medication such as pills or injections work throughout the body.

Various active substances

Antihistamines are relatively widespread. These products are mostly available from the pharmacist without a prescription; they are effective and work fast without causing severe side-effects. They are available as pills, drops or spray.

Nowadays, cortisone preparations - more precisely, glucocorticoids - can be successfully administered locally, i.e. to the area where the symptoms occur (e.g. in the respiratory tract). They are very effective and the side-effects are only minor. Unlike antihistamines, most cortisone preparations are only available on prescription. DSCG is short for disodium cromoglycate. This is a special cell stabiliser that is believed to prevent the secretion of inflammatory messenger substances (e.g. histamine). The success rate is relatively poor, which means that DSCG preparations are hardly ever used nowadays.

Can allergies actually be prevented?

There is no "one way" or guaranteed method of preventing allergies. However, it may help if preventive steps are taken in infancy.

The incidence of allergies and asthma among children and adolescents has increased significantly over the last few decades. In the industrialised countries in particular, the number of allergy sufferers has risen dramatically - there are now around three times as many people with allergies than there were in the 1980s. Appropriate preventive measures can reduce the risk of a child developing asthma, neurodermatitis or another allergic condition by about half.

Which children are at risk of developing allergies?

Unfortunately, there is as yet no reliable test that can determine the risk of a child developing an allergy. However, we do know that the tendency to develop atopic diseases (asthma, neurodermatitis, hay fever, food allergies) is hereditary. For that reason, a review of the family's medical history is the only way in which the child's risk can be determined.

• If neither parent has an allergy, the child's risk of developing an allergy is 0 to 5 per cent.
• If one of the child's siblings has an allergy, the risk is 25 to 30 per cent.
• If one of the child's parents has an allergy, the risk is 20 to 40 per cent.
• If both of the child's parents have allergies, the risk is 50 to 60 per cent.
• If both of the child's parents have the same allergy, the risk is 60 to 80 per cent.

However, whether or not the allergy breaks out also depends on the conditions in which the child grows up. If the child is exposed too soon or too intensively to possible allergy triggers, this can have a significant impact. Environmental factors such as cigarette smoke and air pollutants, both indoors and outdoors, are also responsible for the development of allergies.

Which preventive measures are recommended?

Prevention during breastfeeding

Recent research has shown that fish can help prevent allergies and should therefore be eaten twice a week. One of these meals should consist of oily fish such as herring, salmon or mackerel.

No cigarette smoke

Start your allergy prevention strategy by creating a smoke-free environment for your child. This applies to both parents!

Breastfeed for four months

Children should be exclusively breastfed for the first four months, especially if there is a family history of allergies. If this is not possible, children at risk should be fed a special baby milk. The protein in these products is already split, which reduces the risk of allergic reaction (hydrolysed baby milk). This should be the infant's sole nourishment until the end of the fourth month. Leading experts in this field recommend the use of lightly hydrolysed products, known as HA (hypoallergenic) milk, that have proved their efficacy in scientific studies (e.g. Beba HA). Goat's milk, sheep's milk and soya beverages are not suitable substitutes for breast milk.

Introduce solid foods gradually

Weaning begins by gradually replacing milk meals with puréed foods and transitioning to family meals at the end of the first year. Every infant needs time to become accustomed to solid foods.

Pets

The influence of pets on allergy development is currently a highly controversial subject. It is therefore better to avoid introducing new pets such as cats, hamsters or birds. Depending on the family risk, there is no harm in keeping a pet that was already in the apartment before the child was born.

Recommended vaccinations

Even children at risk of developing allergies should be given the vaccines recommended by the Ständige Impfkommission (STIKO) [German Standing Committee on Vaccination]. Several major studies have shown that vaccinations do not increase the risk of developing allergies or neurodermatitis!

Other sensible measures:

• Use creams and shampoos that are free from fragrance and colourants.
• Do not pierce the child's ears at a young age.
• Do not allow the child to wear fashion jewellery at a young age.
• Do not use children's perfume.
• Regularly ventilate, do not use room sprays, minimise indoor air pollutants.
• Avoid high humidity levels indoors to prevent the development of mould. The relative air humidity should lie within a range of 40 to max. 60 per cent.
• Mould must be removed immediately. The cause of the damage should also be identified so that the mould can be eliminated permanently. Merely painting it over does not solve the problem.

Is suppressing sneezes a good idea if you have allergic rhinitis?

Sneezing does not just make a deafening noise. The respiratory muscles (in the chest and abdomen) "gear up" to speeds that could keep pace with any racing car. A sneeze catapults air, saliva, nasal secretions and germs through the mouth and nose at speeds of up to 160 kilometres an hour.

With this kind of velocity, suppressing a sneeze is not a good idea, because this may force the mucus into the sinuses or even into the ears. Instead, try tensing your abdominal muscles as tightly as possible when you feel a sneeze coming on. This prevents the glottis from opening, which means that the sneeze has no way of escaping loudly.