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An allergy is a faulty or inappropriately vigorous reaction
by the body’s immune system. When working normally, the
immune system will defend the body against infection by producing
special proteins called antibodies to inactivate invading
micro-organisms or foreign particles (antigens).
In people with allergies, the immune system causes a similar
reaction to substances like pollen, housedust mites, mould
spores, peanuts or egg whites, which it ‘thinks’
is an ‘attacker: these are actually harmless to most
of us. Any substance that causes this kind of reaction is
known as an allergen. People who develop allergies
are described as being ‘hypersensitive’ to a particular
allergen.
People who are hypersensitive can develop allergies to a range
of substances, but may eventually grow-out of their allergy.
Although hypersensitivity can be passed on genetically, specific
allergies may differ between family members and some members
of the family may never develop an allergy.
When someone has an allergic reaction their body will release
histamine. It is directly responsible for most of the
local symptoms of allergy: itching, red eyes, nose and skin;
constriction of the airways due to swelling and inflammation
of the lining of the nasal cavities and the lungs.
A more serious – but very rare - type of allergic reaction
in which breathing is restricted and the heart may stop is
known as anaphylaxis or anaphylactic shock.
People known to be at risk must see their GP for advice and
treatment and carry a pack of emergency medicines at all times.
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| Hayfever
(seasonal allergic rhinitis) |
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| Condition |
Hayfever
(seasonal allergic rhinitis) |
| Symptoms |
Itching sensation
in the nose; streaming or watery secretions from the eyes
and nose; sneezing; congestion; itching and redness of
the eyes.
There may also be intense itching in the back of the throat,
caused by drainage of allergens in fluid from the nose
and in the ears.
Hayfever sufferers who are badly affected may also develop
asthma symptoms at the peak of the season as the two conditions
are linked. |
| OTC Treatment |
NB: If you
have seasonal symptoms every year it would be advisable
to start treatment in advance of the pollen season to
help keep your symptoms to a minimum once it starts.
Symptom relief:
- Antihistamines and decongestants.
Antihistamines are usually given in the form of tablets
for hayfever. These can take between half an hour and
several hours from the first dose to reach effective concentrations
in the blood and the affected tissues of the eyes and
nose.
Some antihistamines can cause drowsiness (e.g. chlorpheniramine,
chlorphenamine, diphenhydramine and promethazine.) important
if you are considering driving or operating machinery.
This is made worse by drinking alcohol which should be
avoided.. Other antihistamines have been developed to
avoid this effect. These include acrivastine, cetrizine
and loratadine. These usually work within half an hour.
Symptom prevention:
- Nasal steroids
- Sodium cromoglycate eye drops.
Nasal steroids can be used for relief and prevention.
OTC corticosteroid nasal sprays are not generally recommended
for people under 18 years of age.
(If you have asthma you should check with your GP that
you’re not already taking corticosteroids)
NB: Some hayfever treatments are not recommended for
children aged less than 12 years. Children under 2 years
should always be referred to a GP. |
| Other self-help |
The most effective way of avoiding the symptoms of
hayfever is to avoid the pollen. If you’re prone
to hayfever it may help to stay indoors, if possible,
with the building or car windows closed.
Good air conditioning or air filters can remove 99%
of pollen particles from the air.
Pollen counts are highest in the early morning and late
evening and even precautions taken at these times can
help.
If staying indoors is not practical, you would benefit
from avoiding grassy fields and parks. Also avoid picking
fruit or flowers and stay away from newly mown grass.
It is helpful to wear sunglasses, even on dull days,
and to avoid touching animals that may have picked up
pollen on their coats.
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| Other information |
Up to 12 million people in the UK suffer from hayfever
each year. Children and young adults are the most commonly
affected, although some people over the age of thirty
continue to suffer from hayfever.
Hayfever mostly occurs between May and August and is
at its worst in June and July when grass and tree pollens
are at peak levels.
The nature and severity of hayfever symptoms vary, but
tend to be related to the daily pollen count.
Some external factors can make hayfever worse, such
as cigarette smoke, temperature changes, perfume, aerosols,
some insecticides and pollution such as fumes and smog.
If someone with hayfever symptoms suddenly begins
to have serious breathing difficulties, along with swelling
of the mouth, tongue or throat, or deep eye pain, they
should be referred for emergency treatment at once.
These symptoms may indicate the start of anaphylactic
shock.
Antihistamines rapidly improve symptoms in over 70%
of hayfever cases, being effective in relieving the
itching of eyes, nose and throat, sneezing and nasal
secretions. Antihistamines, however, have less effect
on nasal congestion.
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| Perennial allergic rhinitis |
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| Condition |
Perennial
allergic rhinitis |
| Symptoms |
Itching sensation in the nose; sneezing and congestion.
There may also be intense itching in the back of the
throat, caused by drainage of allergens in fluid from
the nose and in the ears.
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| OTC Treatment |
- Antihistamines to reduce the itching and sneezing
and to help dry the runny nose.
- Nasal sprays containing a corticosteroid or sodium
cromoglicate can be used to prevent and alleviate symptoms.
However, as long-term treatment will be necessary, the
use of corticosteroids is best initiated by a GP.
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| Other self-help |
If you are aware of the source of your hypersensitivity,
try to avoid the allergen.
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| Other information |
Different allergens
can cause hayfever-like symptoms all year round, e.g.
mould spores, housedust mites and animal dander.
The eyes are not affected in perrenial allergic rhinitis. |
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| Condition |
Allergic
conjunctivitis |
| Symptoms |
Eyes swell
and become red, itchy and watery. |
| OTC Treatment |
- Various eye drops and nasal sprays that include antihistamines
such as antazoline, azelastine and levocabastine.
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| Other information |
Before using OTC products, check with your doctor that
symptoms are actually being caused by an allergy.
If you suffer from asthma you may need advice from your
GP about appropriate treatment.
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| Condition |
Insect bites |
| Symptoms |
Inflammation
and/or itching where the skin has been bitten.
Some people may experience a large, painful inflammation
of the skin and the soft tissue underneath it. |
| OTC Treatment |
- A thin layer of cream, lotion or spray preparation
containing an antihistamine and/or a local anaesthetic
should be applied to the site of the bite. The antihistamine
reduces the inflammatory response and relieves itching.
A local anaesthetic reduces any pain.
- Other soothing products that reduce itching (called
antipruritics) can also be used.
- Products containing hydrocortisone can also be used
to bring down the swelling and inflammation.
- If you have several bites that are causing itching
over a large area you may want to take antihistamine
tablets. The older antihistamines also have a sedative
effect and will help people with severe itching to sleep.
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| Other information |
Biting insects like mosquitoes and midges, feed off
human blood. When they land on their prey they inject
a local anaesthetic into the skin to prevent the bite
being felt. They then inject an anticoagulant which
prevents the blood clotting whilst they are feeding.
These substances will be recognised as '‘foreign’
by the body and an immune response will occur.
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| Condition |
Insect stings |
| Symptoms |
Pain and local
inflammation of the skin.
If a person has become sensitised to the toxins found
in a bee or wasp sting there is a possibility that they
might experience an anaphylactic shock. Symptoms of this
are: a widespread blotchy rash; puffy face and eyes; difficulty
in breathing and rapid pulse. This requires urgent
medical help. |
| OTC Treatment |
- A thin layer of cream, lotion or spray preparation
containing an antihistamine and/or a local anaesthetic
should be applied to the site of the sting. The antihistamine
reduces the inflammatory response and relieves itching.
A local anaesthetic reduces any pain.
- Other soothing products that reduce itching (called
antipruritics) can also be used.
- Hydrocortisone can also be used to bring down the
swelling and inflammation.
- If you have several bites that are causing itching
over a large area you may want to take antihistamine
tablets. The older antihistamines also have a sedative
effect and will help people with severe itching to sleep.
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| Other self-help |
The first step
in dealing with stings is to remove them carefully if
they are visible. This should be done with caution as
squeezing a sting could force more toxin into your skin.
Grasp the very base of the sting not the small sac which
contains the toxin.
Clean the area with warm water and soap and apply a cold
compress directly to the area. |
| Other information |
Stinging insects like bees and wasps inject a potent
irritant (venom) into the skin that can be extremely
painful.
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| Contact eczema (sometimes
known as dermatitis) |
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| Condition |
Contact
eczema (sometimes known as dermatitis) (see "Skin
& Scalp") |
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| MedicineChestOnline.com
is a directory of medicines and food supplements
that are available 'over the counter' (OTC) from
your pharmacist. The links below will take you to
pages detailing products which may help treat or
relieve the following symptoms: |
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NHS
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Contains a list of information on health, including
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