Allergies occur when the immune system is triggered, usually by something in the environment such
as dust or pollen. There is also a hereditary susceptibility to allergic disease. The major areas of the
body that have contact with the environment (breathing passages, nose, eyes, skin and gut surfaces)
have a large number of immune cells to protect them, so this is why these areas are commonly
involved in allergic reactions. Symptoms of allergy vary according to the severity of the allergy and the
area affected. Many people have more than one type of allergy (eg, eczema and asthma).
1. Hay fever (nasal and eye symptoms)
2. Asthma.
3. Eczema
4. Food allergies
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Hayfever
The symptoms of hayfever include a frequently itchy nose with clear discharge as well as itchy, mildly red and watery eyes. Hayfever affects almost half the population in Australia at some stage in their lives. Unfortunately, if it is due to allergy to pollens and grasses (usually occurring between October and April each year), it tends to recur during the same season in future years. Hayfever is often also triggered by perfumes, cigarette smoke or air conditioning.
As time goes on, a significant number of people (roughly one third of sufferers) find they get symptoms throughout most of the year. Occasionally moving to another region may mean symptoms go away, either for a while or sometimes permanently.
Treatments for Hayfever
There are several excellent medications available from the pharmacy to manage hayfever. For acute symptoms the decongestant nasal sprays work well in most people, but should not be continued for more than five days as the lining of the nose begins to depend on them. The same applies to antihistamine eye drops.
It is wise to use a preventative, such as a weak steroid nasal spray, if symptoms are occurring over weeks or months. These will take several days to begin to work, so a decongestant, or the more expensive alternative, a non-sedating antihistamine tablet, may be taken in the meantime. Control of the nasal symptoms will often mean the eye symptoms improve, but sometimes lubricant eye drops are needed. If symptoms are severe, not responding or are complicated, medical advice is wise. An interesting point to note is that asthmatics that also have hayfever symptoms will tend to find their asthma is harder to control. |
Asthma
Asthma is a common allergic disease which causes airways to narrow and swell making it harder for
the person to breathe when exposed to certain triggers. In cases of mild asthma this causes reduced exercise tolerance and often an intermittent night-time or early morning cough. The advice of a doctor
should be sought, as treatments are very effective and have few side effects, even if they need to be
used regularly. In severe attacks the person may have difficulty breathing normally at rest, or may even
have to slow down their speech. These are more serious symptoms. Immediate treatment should be
sought or 000 should be phoned.
Interestingly, antihistamines don’t work on the symptoms of asthma. Doctors like people with asthma
to have an ‘asthma plan’ for management of the condition, as viral infections, dust, exercise and
seasonal changes are common causes of a flare up of symptoms.
Eczema and Dermatitis
Eczema is a common immune reaction within the skin to something in the environment. Dermatitis is
an allergy caused by direct contact to a substance. The symptoms are similar, varying from mild
redness and itch to more severe weeping, cracked, bleeding, red irritable skin.
Contrary to common belief, only 1% of cases of eczema are due to food allergy. Avoiding overheating, moisturising and cleaning the skin with sorbolene or soap-free washes are the mainstay of prevention
and treatment of eczema. Not coming into contact with known triggers is important. Steroid creams and some newer medications may be needed.
Food Allergies
Food allergies are less common than and often confused with food intolerances.The difference is that
an allergy is caused by an immune reaction and may occur with any degree of exposure to the
substance one is allergic to, but an intolerance causes no symptoms when the substance is taken in
small amounts.
Examples of food intolerances include bloating from bread or pasta or a gurgling stomach and
nausea
with too much milk. It can be very difficult to differentiate between food allergy and intolerance, and
referral to an immunologist for skin prick testing and specific blood tests may be needed.
A food allergy may cause nausea, stomach cramps, vomiting, diarrhoea, lip and facial swelling and
even asthma or skin rash. Such a reaction may be immediate (and may lead to anaphylaxis), or may
be less severe and delayed.
The food responsible for delayed reactions is often harder to identify. Common foods that cause
allergies are milk, eggs, nuts, fruit, fish, seafood and wheat. Prevention of food allergy requires total avoidance of the suspect food, including the use of separate pans when cooking if the allergy is
severe. Sometimes desensitisation injections are advised by an immunologist.
Anaphylaxis
The most serious (but luckily uncommon) allergic reaction is called ‘anaphylaxis’. This requires immediate medical attention from the nearest doctor and/or ringing 000. The symptoms of anaphylaxis are a sudden release of chemicals on the surface of the skin, mouth and breathing tubes. The result is swelling of the face, tongue and lips, itchy rash over the skin and shortness of breath due to spasm of muscles around the breathing tubes (identical to asthma) and the reaction may become life threatening. This may be rapidly reversed by an injection of adrenaline and antihistamines.
An ‘anaphylactoid’ reaction is much less severe and is a wide spreading itchy rash, sometimes with mild facial swelling. It needs medical review as, if it continues over many hours or days, it can turn into anaphylaxis.
Common causes of anaphylaxis include bee and wasp stings, foods (especially peanuts, fish, seafoods and certain fruit), latex and occasionally injectable medications. In a significant number of cases no cause is found. Anyone who has had an anaphylactic reaction needs to find out what they were exposed to that caused it and how to avoid it in the future.
It is wise to see a doctor who specialises in allergies (an immunologist), as most people who have had such a reaction are advised to carry with them at all times a self-injecting kit containing adrenaline and an antihistamine.
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© Australian Pharmaceutical Industries Limited 2006
Produced by API, 11 Grand Avenue, Camellia NSW 2142 ABN 57 000 004 320
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