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Hay
fever
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Causes
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Oral
allergy syndrome
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Hay
fever treatment
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The
pollen count
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Hay fever is caused by an allergic reaction to the pollen from grasses,
plants and trees and in some cases fungal spores. A person suffering from hay fever may be
allergic to anything from one to very many types of pollen. Symptoms
include sneezing, runny itching eyes and nose, sore throat, headache and tiredness.
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In the UK,
grass
pollen is the commonest cause of hay fever but also important are pollens from trees such as
alder, hazel, birch and plane, and from weeds such as nettles and from garden plants.
Some
people suffer symptoms similar to hay fever all the year round due to dust
mite allergy or pet allergy and this condition is known as
perennial
allergic rhinitis.
perennial
allergic rhinitis.
Causes of hay
fever
If you suffer
from allergic symptoms, you can only know for certain if you have an allergy if you have it
confirmed by an allergy assessment. This includes enquiring about symptoms, history of
allergy, exposure, family history etc., to get a good picture of your situation and to see what
can be done to help
 When
hay fever is caused by allergy to pollen grains, skin prick testing is usually helpful. These
tests involve a gentle prick through a drop of allergen extract on the surface of your arm
(pictured left). This may result in a small swelling and a reddening of the skin, suggesting
that you have an allergy.
An
allergy blood test that looks for specific allergy antibodies
(IgE antibodies) is often recommended to confirm the test
result. If specific antibodies towards one or more allergens are found in the blood, it means
that you are sensitised and are liable, either now or at some time in the future, to have an allergic reaction when exposed to these substances.
In
the UK, hay fever is mainly caused by grass pollen allergy, but tree
pollens also cause symptoms for some patients. Certain weeds, garden
flowers and flowering shrubs can also cause symptoms in some
patients. Occasional patients are allergic to a wide range of
pollens, and such patients can have symptoms due to pollens from late
January until early October.
Symptoms
indistinguishable from pollen allergy can also be caused by the spores
from moulds and fungi.
Oral
allergy syndrome
Some hay fever
sufferers experience an allergy of the mouth and throat called oral
allergy syndrome.
In most cases symptoms occur throughout the year, although for some the symptoms only occur during the pollen season.
In the UK, it is commonest amongst patients who turn out to be allergic to the pollen
of the birch tree, although some grass pollen sensitive patients are also affected.
In the most common form, sufferers experience a localised swelling or itching of the
lips, mouth, tongue or throat immediately after contact with certain fruits or vegetables that
turn out to contain similar allergens to those present in the pollen to which they are also
sensitive.
Reactions usually follow contact with the fresh fruit or raw vegetable (sometimes even
handling them), although reactions to cooked foods can sometimes also occur.
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Hay fever
treatment
There
are three main ways of reducing the symptoms of hay fever. These are
avoidance,
drug treatments and
desensitisation.
Drug
treatments
A wide variety of
treatments is available. Different patients have different patterns of symptoms and
may therefore not all may be helped by the same treatments. Depending on the patient and depending on the situation,
there are a number of suitable drug treatments and information about the following treatments
is provided:
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Nasal
steroid sprays
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Steroid
injections
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Antihistamines
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Steroid
tablets
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Desensitisation
treatment
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Other
treatments
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 Unfortunately,
it is just when grass pollen counts tend to be at their highest in the UK that
school, college and university students face their main examinations. Many
people feel generally ill with hay fever, and their performance at examinations
is impaired by the allergic reaction and often also by the antihistamines they
take.
June is also a popular month for
weddings and outdoor events, and severe hay fever sufferers run the risk that
their hay fever could seriously upset a happy day.
Faced with this problem, many
simply put up with it, whilst others depend on antihistamine tablets, steroid
nasal sprays, or herbal remedies from the chemist. They may assume that their GP
can offer them no treatment that is any more effective. This is not correct, as
a great deal can be done.
Nasal Steroid
sprays
Steroid nasal sprays are most effective, but only if
the treatment is commenced about week before the sufferer knows from previous
experience that the hay fever is due. The spray is then used
regularly every day whether there are symptoms or not, supplemented with
antihistamine tablets if necessary, until the season is over. This regime makes
sense because if the hay fever is allowed to develop the nose gets blocked, so
nasal sprays become useless because the spray cannot get inside the nose.
Antihistamines
It is important that the antihistamine chosen is one of the 'new generation'
type, some of which are only available on prescription. The older type such, as
chlorpheniramine (Piriton®), are still available under different
brand names although they may be less effective than those available on
prescription, and they may cause unacceptable drowsiness.
Steroid Injections
Depot steroid injections. have been given for many years for hay fever, and are
very effective, but there are serious objections to this treatment. Quite a
large dose of steroid is contained in the depot, and the drug is released into
the circulation at a steadily decreasing rate over about six weeks. The amount
released bears no relation whatever to the pollen count which varies
dramatically from day to day and hour to hour. Steroid tablets (see below) are
just as effective, and the dose can be more precisely matched to the
symptoms.
If the depot injection is given too soon it may all have been
absorbed before the end of the season, symptoms recur, and another injection may
be required. Most importantly, this treatment is have been found very
occasionally to cause necrosis of the head of the femur, requiring hip
replacement. Although this is a rare complication, it is clearly not reasonable
to run even this risk for controlling hay fever. Also the injection sometimes
causes a small dimple due to absorption of fat.
Steroid
Tablets
In severe cases of hay fever that does not respond well to the standard
treatments, a few oral steroid tablets can be prescribed to be taken for a few
days when the hay fever is at its worst, or if there is an important occasion
such as an important examination, a wedding, or a job interview. This treatment
is 100% effective, and because it is taken for a short time only there is no
significant risk of any side-effect because the total dose is much less than
that given in a depot injection.
Desensitisation
An important reason to identify which
pollens are responsible for the symptoms is the recent development of newer
forms of desensitisation treatment. Such treatment can be considered when
symptoms are severe, and when the standard treatment fail to provide
reasonable relief.
This type of treatment for allergy and hay
fever has always been far more widely used in other countries than in the UK.
This form of treatment (pioneered in the UK nearly 100 years ago) became
popular as an alternative to drugs, but unfortunately the original form of
this treatment was not without risk. So in 1985 the Committee on Safety of
Medicines placed restrictions on its use, and it declined in popularity.
Recently,
very safe forms of
allergy desensitisation treatment have been
developed, and this treatment is becoming popular again. Many
successful clinical trials have been done, and these have involved two
basic methods. One form of this allergy treatment is known as
subcutaneous
immunotherapy and involves a course of
injections that are given weekly in the early part of each
year. A more recently introduced form of this allergy
vaccine treatment is called
sublingual
immunotherapy and requires the patient to place some of the allergy
vaccine as drops under
the tongue several times each week starting several weeks
before the hay fever season begins.
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© Dr. Harry Morrow-Brown. All Rights Reserved.
The pollen
count
A
pollen chart that shows the
pollination times for the main UK allergy-provoking pollens is
provided These seasons may vary by up to
three weeks depending on which part of the UK, and depending on the
climatic conditions. In recent years there has been a tendency for
pollination to start earlier as a result of milder winters, and warm
spring weather conditions.
During the main
pollen season, counts that give an estimated forecast of the airborne load for individual pollens (tree
pollens until the end of May, the grass pollens until August) are collected by
the National
Pollens and Aerobiology Research Unit
at the University of Worcester. Pollen
forecasts are then prepared by using the pollen count information,
knowledge of local vegetation and weather patterns. The pollen forecasts can help hay fever
sufferers to plan their activities and medication. The index of risk relates to the
quantitative categories as follows:
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Index |
Conditions |
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| 8-10 |
Very High Risk |
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| 6-7 |
High Risk |
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| 4-5 |
Medium Risk |
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| 1-3 |
Low Risk |
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References:
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Perennial
rhinitis. |
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Saleh,
H.A. and Durham, S.R. (2007) British Medical
Journal 335(7618), 502-507. |
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Patient
and physician perspectives on the impact etc, |
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Scadding,
G.K. et al. (2000) Clin Otolaryngol &
Allied Sci 25(6), 551-557.
[Abstract] |
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BSACI
guidelines for the management of allergic and
non-allergic rhinitis. |
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Scadding,
G.K. et al. (2008) Clin Exper Allergy
38(1), 19-42. [Abstract] |
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Prevalence
and rate of diagnosis of allergic rhinitis in
Europe. |
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Bauchau,
V. and Durham, S.R. (2004) Eur Resp J.
24;758-764. [Abstract]
[Free
Full-text] |
Recommended reading
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