EUROPEAN
RESPIRATORY
JOURNAL
November issue
(Vol. 24, Number 5)
One in ten Europeans have allergic rhinitis
without realising it
Allergic rhinitis affects 20% of Europeans, but only half of all
cases are diagnosed, according to an epidemiological study
conducted in six western European countries, whose results
are published in November's ERJ. Millions of patients are
missing the chance to get treatment and improve their quality
of life.
Allergic rhinitis, of which hay fever is the seasonal form, has a familiar range of
symptoms: itching of the nasal passages, sneezing and a blocked nose, as well as
a large number of secondary symptoms. Like all allergic conditions, it is
becoming increasingly widespread in developed countries.
Though benign in appearance, it is a disabling condition, which damages
sufferers' quality of life, sleep and productivity. Moreover, it often heralds the
development of asthma.
Since patients tend not to take the condition seriously and doctors and
pharmacists do not always recognise it, allergic rhinitis tends not to be treated
adequately.
How many Europeans are affected? How are they identified?
The European Respiratory Journal (ERJ) takes stock of the situation in detail for
the first time, with the publication of this major epidemiological study covering
Belgium, France, Germany, Italy, Spain and the UK.
53 million Europeans affected …
To determine the prevalence of allergic rhinitis and diagnosis rates, the
researchers first held telephone interviews with almost 10,000 people,
approximately 1,600 in each country. The purpose of this first stage was to
identify individuals who could be clinically diagnosed with the condition.
Of the subjects, 40% could be considered as potentially suffering from allergic
rhinitis, either because they had the relevant symptoms (21%) or because they
already knew or believed that they had the condition (19%). This first round of
interviews also elicited that only 13% of cases had been diagnosed by a doctor
and only 11% of subjects were being treated for the condition.
The researchers then asked the potential sufferers to attend for a confirmatory
diagnosis (clinical examination and specific IgE dosage), and 724 subjects
complied.
…but only half of cases identified
The results published in the ERJ show that the diagnosis of allergic rhinitis was
confirmed in 57% of cases, which, in the context of the initial subject group,
represents a prevalence of 23%, or more than one person in five.
In 45% of cases, this was the first diagnosis of allergic rhinitis, which means that
one person in ten has the condition without knowing it!
"These figures show that allergic rhinitis is very common and heavily underdiagnosed", lament the article's authors, Vincent Bauchau (UCB Pharma, Braine
l'Alleud, Belgium) and Stephen Durham (Imperial College, London, UK).
"The reason is probably inadequate information about this type of illness. Our
analysis showed that access to health care is probably not the issue", Bauchau
emphasises.
Different diagnostic rates depending on severity of symptoms
Besides the lack of information, the fact that allergic rhinitis is sometimes not
very pronounced or its symptoms not very evident can also contribute to underdiagnosis. "Some people probably get used to living with the condition, or don't
realise that treatments are available", suggests Bauchau.
Conversely, allergic rhinitis is more obvious, and so more readily diagnosed,
when symptoms are exacerbated by certain environmental allergens, such as the
herbaceous pollens that cause classical hay fever. It is also easier to identify in
asthmatic patients, since asthma and allergic rhinitis often occur together.
"Indeed, it is believed that most asthmatic patients suffer from allergic rhinitis",
Bauchau emphasises. "And more women tend to be diagnosed with it, probably
because they are more aware of their health and more likely to go to the doctor."
Intermittent rhinitis most common
The study published in November's ERJ also shows that the allergens
responsible for this condition are most commonly grass pollens (52%), followed
by house dust mites (49%), tree pollens (33%), herbaceous pollens (27%),
animal dander (26%) and mould spores (10%).
Outdoor allergens affected 63% of patients, while 55% were affected by indoor
allergens. However, a third of patients were sensitive to both types of allergen.
The ERJ study is, moreover, the first such large study to examine the prevalence
of the various types of rhinitis, and it contains interesting data on this aspect.
For example, it reveals that what the ARIA (Allergic Rhinitis and its Impact on
Asthma) Initiative terms "intermittent" rhinitis (where symptoms are
experienced for less than 4 days a week and last for less than 4 weeks) affects
some 70% of cases, whereas 30% of sufferers experience "persistent" disease
(symptoms occurring in bouts lasting for more than 4 days per week and for
more than 4 weeks).
Finally, this European study confirms that the condition is more common in the
north of Europe than in the south: while it affects 28.5% of people in Belgium
and 26% in the UK, the level falls to 16.9% in Italy.
"This reflects the global north-south divide in the prevalence of allergic diseases
seen in other studies", Bauchau recalls.