Curiously, allergies are more common now than in earlier times. According to Allergy UK, the rates of allergy have increased in all countries undergoing industrial development and affects up to 30-35% people at some stage in their lives. There has also been a change in the types of allergy on the increase, from asthma and hay fever a few years ago, to food allergies now. This is especially true for children and it is estimated that nearly 50% of youngsters in the UK are diagnosed with an allergy.
An allergic response occurs when the body’s immune system responds to a particular substance either ingested in food or in the environment as though it is a threat like an infection. Antibodies are produced to ‘fight’ the allergen and this is known as the ‘immune response’. The substance which is the allergen is harmless and causes no reaction in people who are not allergic. When someone is exposed to the allergen again the antibodies produced at the first exposure release a number of immune system chemicals, such as histamine, and these cause the symptoms.
Allergic responses to an antigen may be mild or severe and may even be fatal. The type of symptoms depends, to some degree at least, on the antigen, for example; pollen causes hay fever the symptoms of which are sneezing, itchy nose and eyes, stuffy nose, red, watery swollen eyes. Food antigens such as nuts result in a tingling mouth, swollen lips, tongue, face or throat, hives, anaphylaxis. Insect bites can cause swelling round the bite site, hives and itching all over body, cough, wheezing, anaphylaxis. Drugs such as penicillin may trigger a rash, itchiness, swollen face, wheezing, anaphylaxis. Other antigens may cause eczema, the signs of which are itchy, red and flaky skin.
Anaphylaxis is the most severe allergic reaction and is characterised by swelling, hives, lowered blood pressure and dilated blood treatment. It requires immediate urgent treatment as it can cause death within a short space of time.
There are some known risks which increase the likelihood of developing allergies such as having a family member who suffers from an allergy. This does not necessarily mean that the two family members will have the same allergy but allergic responses seem to run in families. Also, having one allergy seems to increase the chances of developing another and it is quite common for a child who had eczema as an infant to then develop a food allergy.
The hygiene hypothesis
There are two main theories that attempt explain the increase in allergies. As stated earlier, the rise is marked in industrialised countries so there is speculation that it is linked to pollution. However, the alternative theory is that it is due to increased cleanliness in the home – the so called hygiene hypothesis. Consider all the TV adverts which promote spray solutions or steam machines where the emphasis is on destroying hidden bacteria to keep babies and children safe. The hygiene hypothesis suggests that by keeping the environment too clean, babies are not being exposed to sufficient bacteria to allow their immune systems to develop properly.
This hypothesis has been supported by a recent Swedish study which found that children who lived in homes where dishes were hand washed were less likely to have allergies than those children who lived in homes where dish washer machines were used. Previous research had shown that dish washers are more efficient than hand washing in terms of removing bacteria. In this study the parents or guardians of 1,029 Swedish children aged 7 to 8 were surveyed. 23% of children from the hand washing homes had a history of eczema compared to 38% of children from the dish washer homes. The researchers point out that this just shows a relationship rather than definitely proving causality.
Living with an allergy
Managing allergies may be very simple in that, if possible, the antigen should be avoided. If someone is allergic to shellfish, that is relatively easy. However, as hay fever sufferers know only too well, avoiding pollen is so much harder. Even so, there are steps which can be taken to reduce exposure such as closing windows and not going for walks in areas where the pollen is strong.
Recently there has been a suggestion that avoiding the antigen altogether is not the only option and that gradual exposure may hold the key to people achieving a cure. However, it must be stressed that people should not try and do this on their own. A controlled randomized trial in Melbourne involving 62 children who were allergic to peanuts, found that of those who received a dose of probiotic with a peanut protein in increasing amounts 80% were able to tolerate 2g of peanut protein a day (equivalent to about 8 peanuts a day). Again there is a suggestion that by carefully selecting the foods we give babies when we wean them, maybe we prevent then developing antibodies at a critical age. In the past there were no special baby foods. However, please do not give infants peanuts in any form as more research needs to be done to confirm this.
Treatment of an allergic response depends on the severity. Anaphylaxis is a serious medical emergency and Epinephrine is the drug of choice. Known sufferers carry it with them in the form of an EpiPen which they can inject into their thigh in an emergency. They should still go to A&E even if they feel fine afterwards in case the reaction is still there when the drug wears off. Otherwise, for milder allergies anti histamines are usually prescribed. Bronchodilators may also be used if there are breathing problems or asthma like symptoms.
This Allergy Awareness Week spare a thought for the many sufferers of allergy and, if you are one yourself, take care of yourself. It is not easy to always try and avoid a substance which is quite harmless to most people but may be toxic to you. However, with help and care, most allergies can be managed so normal life is not too disrupted.