Allergic conditions are on the rise in westernised countries and recent investigations have found that hospitalisations for anaphylaxis (a severe allergic reaction often involving more than one body system), urticaria (hives), and angioedema (allergic swelling of the face, lips and tongue) have been increasing since 1990.
In a study published this week in the Journal of Allergy and Clinical Immunology, Leanne Poulos and others from the Australian Centre for Asthma Monitoring (ACAM), a collaborating unit of the Australian Institute of Health and Welfare (AIHW) report the prevalence of these conditions by looking at records of hospital admissions and deaths in Australia from 1993-2005.
The researchers sought to characterise the cause and nature of the conditions by examining data on patient age, sex and the presence or absence of a food trigger for the event.
They have found that, as in the UK and US, admissions increased in all three conditions and especially for food-related anaphylaxis in children under 5 years of age.
Co-author Professor Guy Marks said, 'We examined recent time trends in hospitalisations and deaths attributed to anaphylaxis, angioedema and urticaria in Australia, and found that over a 12-year period to 2004-05 there was a continuous increase in the rate of hospital admissions for each of these conditions, but that the nature and causative factors differed between adults and children.'
Hospitalisations attributed to anaphylaxis more than doubled over the study period with the most substantial increase being for anaphylaxis triggered by food.
While there was an increase in all age groups the largest increase was among young children, particularly boys.
There was also an increase in admissions attributed to angioedema among older people, which may be related to adverse reactions to medications.
Among children, admissions for allergic conditions were more common in boys than girls but among adults the gender difference was reversed.
The authors could draw no direct conclusions about underlying reasons for increased rates of hospital admission for these conditions. The increase may reflect an increase in the incidence of these conditions or an increase in their severity, or a combination of these, over the study period.