Allergy
- Risk factors
- Allergy testing
- Treatment
- Useful links
Allergens are particles/substances commonly found in the environment that trigger an immune reaction in sensitive individuals. This type of reaction is often termed an allergic reaction.
Common allergens include:
- Pollen (e.g. from grass, birch trees, nettles)
- Dust mites
- Mould spores
- Pet dander – small scales from animal skins or hair (e.g. from cat, dog, horse)
- Food (e.g. shellfish, peanuts, milk, egg)
- Insect stings (e.g. from wasps and bees)
- Medicines (e.g. some antibiotics).
Allergy symptoms vary but common symptoms include: runny nose, sneezing, itching; rashes, swelling, difficulty breathing. The following are different type of allergic responses; click on the links to learn more:
The following are different type of allergic responses; click on the links to learn more:
Risk factors
There are a number of allergy risk factors. These include:
- Family history
- Environmental factors
- Exposure to allergens
It is still unclear why there is a growing rise in allergies with some researchers attributing increase in number of allergy sufferers with advances in modern lifestyle such as having fitted carpets in the home which encourages the growth of house dust mites etc.
Allergy testing
There are tests available to determine if you are suffering from allergies. This can involve carrying out skin and/or blood tests. A positive allergy test will help to narrow down the list of suspected allergens but it is important to give your GP a detailed description of your exposure to allergens.
Skin test
Skin prick tests are safe and cause very little discomfort. As few as 3 or up to about 25 allergens can be tested at once.
A drop of a common allergen e.g. dust mites, mould, pollen, cat and dog dander is placed on the skin – usually on the forearm – and a needle is passed through the extract to make a tiny puncture in the skin.
An allergic response to a particular allergen is noted if a raised bump (or hive) is observed at the area of skin that was exposed to that allergen (usually within 15 minutes of exposure). The skin will remain looking normal, if there is no allergic response to the allergens.
SIgE test
The specific immunoglobulin E (or SIgE) test is a blood test that can be used instead of a skin prick test to detect allergies.
It can be very useful in confirming whether you have been sensitised to a substance. The test works by measuring the amount of certain antibodies in your bloodstream in response to specific allergens.
Challenge test
If your allergic reactions are not severe, your GP might decide to carry out a challenge test. This test is often performed on patients with food allergies, who have previously undertaken a skin prick test or sIgE test with positive responses against specific allergens. [insert link to food intolerance page]).Challenge tests are usually carried out in a hospital/clinic environment.
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Treatment
Trigger avoidance
It is quite possible for people with asthma to have more than one allergen. If you have an allergy, or multiple allergies, it is extremely important to minimise or completely avoid exposure to those allergen(s). Your GP/Practice nurse should be able to provide advise on how to avoid triggers and reduce allergens in the home.
Tips to avoid/minimise exposure to triggers
Avoid smoking or exposure to second-hand smoke. Although smoking is not normally directly related to allergies, tobacco smoke has a negative effect on asthma; it worsens asthma symptoms, reduces the effectiveness of asthma medications and is a risk factor for the development of childhood asthma.
Some allergen-specific recommendations are detailed below.
Seasonal pollens or outdoor moulds: air conditioning, or other filtration
Systems, can be useful at keeping allergen particles found in the air out of the home. If your allergy test results identify specific pollens that you are allergic to, it may be beneficial to avoid outdoor environments likely to have high levels of seasonal pollen (e.g. fields or woods).
Other useful tips include: wearing sun glasses; staying in during the early evening when pollen counts are at their highest; fitting pollen filters in the car, and using tumble dryers during the pollen season rather than allowing clothes to dry in the fresh air.
Pets: ideally, pets should be re-homed and the house thoroughly cleaned after they leave. If you have a pet allergy, but are reluctant to re-home your pet, a combination of other measures might still be useful. For example, you could try confining the pet to one room downstairs. Other measures include keeping the pet out of the bedroom, using allergy-proof mattresses and pillow covers, frequent cleaning of bedding, use of special high-efficiency particle arrest (HEPA) filtration, use of HEPA vacuum cleaners, and avoidance of direct contact with the pet.
Mould: if you have a mould allergy and live in damp and visibly mouldy home, you should try to find alternative housing that is free of dampness and
mould. If this is not possible, try to reduce dampness by fixing leaks, using dehumidifiers, removing damp carpets, washing mouldy surfaces with
a weak bleach solution, and HEPA filtration to filter mould spores from the indoor air.
Dust mite: try a combination of activities to reduce dust mite exposure, such as using special allergen-impermeable mattress and pillow covers and avoiding having lots of soft furnishings (e.g. rugs, cushions and throws) and soft toys in the home. However, these measures are expensive and the regime is difficult to maintain.
Allergy medication
Drugs used to treat allergies aim to:
- Treat the symptoms of the allergy
- Steroids (topical, inhaled or nasal) help to reduce inflammation
- Decongestants to clear blocked airways
- Antihistamines to reduce itch
- Reduce the body’s immune response when exposed to an allergen (i.e. immunotherapeutic agents).
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Useful links