Trends show an increase in prevalence of hay fever, eczema and other allergic disorders in children

A new study published online on September 1st 2006 has provided high-class information about the prevalence of allergic diseases. Researchers in the UK collated information from national studies and surveys right back from 1971 (when data on allergic diseases first became available) right up until the most recent research. Specifically they aimed to identify any trends in the incidence of allergic diseases. Striking results showed a significant rise in the prevalence of hay fever and eczema in children and marked rises in the numbers of hospital admissions for food allergies and anaphylaxis (severe allergic reactions).

Allergic disorders, such as asthma, hay fever and food allergies, are caused by an exaggerated or inappropriate immune response to a particular substance. Exposure to allergens such as dust or pollen triggers the immune system to produce antibodies and create a protective immune response. When the immune response is excessive it leads to symptoms such as sneezing, wheezing, rashes or difficulty breathing, which can be life threatening. Allergic conditions are now very common in the Western world. They can affect patients' day-to-day lives, increase patient mortality and cost the healthcare system significant amounts in resources for treatment. There is some evidence that the incidence of allergic disease of specific organs, namely hay fever, asthma and eczema (allergic skin condition), is increasing. Researchers in the UK aimed to investigate this claim further by examining the rates of diagnosis, symptoms, hospital admissions and treatments of various allergic conditions over the last three decades. They did this by pooling data from several national surveys and datasets conducted from 1971-2004 to detect any trends in the data. In particular they looked at the following allergic conditions- anaphylaxis, angiooedema (swelling and fluid accumulation typically in the face and airways), food allergies, urticaria (hives), eczema, conjunctivitis and hay fever. Asthma was not considered in this study as it was a large enough condition to be considered separately. Researchers also compared the prevalence of allergic conditions between adults and children. Results showed that diagnoses of hay fever and eczema in children have tripled in the last three decades and that GP consultation rates for these disorders have doubled. However, these rates have stabilised over more recent years. Other data showed significant rises in hospital admissions for systemic allergic conditions with rates of admission for anaphylaxis and food allergies rising by 700% and 500% respectively. In addition, GPs and other medical practitioners are prescribing more drugs for allergic disorders, in particular anaphylactic reactions where ten times more prescriptions are given today compared to in 1991.This study therefore proves that there has been an increase in incidence of several allergic disorders over recent decades. However, the data is still limited and more research and surveillance is needed to determine the importance of these findings. The results may just be associated with changes in diagnostic procedures and other healthcare factors but researchers think that there has been a real rise in prevalence of these disorders. Therefore, the changes in rates may actually mean the factors causing allergic disease (such as environmental influences) are changing or that people are becoming more sensitive and susceptible to these diseases. In this case, the data and further research may be helpful to identify new causes and lead to improvements in management.