Allergy A-Z
More detailed information on selected allergy topics and Imutest™ will be available soon from our download library.
Acaricides
Acaricides are chemicals used to destroy house dust mites and their allergens in carpets, soft furnishings and bedding.
Allergens
Allergens are substances such as those found in house dust mites, pollens and foods that can trigger allergic reactions
Allergic march
The allergic march is the tendency for babies and young children with eczema to develop asthma and then other allergy related diseases such as rhinitis as they grow older.
Allergy avoidance
Allergy avoidance is the prevention of allergic disease by reducing contact with the known allergen triggers
Allergy Check
Imutest Allergy Check is a quick and convenient way to identify whether you have high levels of allergy antibodies (IgE)
Allergen extract
Allergen extracts are manufactured by pharmaceutical companies under controlled conditions for use in desensitisation vaccines or for allergy tests such as the skin prick test, Imutest and other blood tests.
Allergies
There are different types of allergic reactions but the most common are those involving the allergy antibody known as immunoglobulin E (IgE) and is related to diseases such as food allergy, hayfever, eczema and asthma.
Anaphylaxis
This is the severest form of an allergic reaction where the cardiovascular system is affected. People at highest risk of anaphylactic reactions include those with an allergy to foods such as peanuts and shellfish or insect stings from bees and wasps.
Antibodies
Antibodies are proteins found in your blood and are produced by your immune system. There are five types of antibodies (also known as immunoglobulins) ie. IgG, IgM, IgA, IgD and IgE. IgG antibodies are produced in the largest quantities (about a million times more than IgE) and is normally our first line of defence against viral infections.
Antihistamines
Antihistamines are a group of allergy drugs - most of which are now available without prescription from pharmacies and supermarkets. They can be effective in controlling the allergic reaction by preventing the binding of histamine (which is produced by mast cells during an allergic reaction) to histamine receptors thereby suppressing some of the inflammation associated with allergic reactions.
Asthma
When a person with asthma comes into contact with an asthma trigger such as an allergen to which they are sensitive to, the muscles around the walls of the small tubes that carry air in and out of the lungs tighten. The lining of the airways then becomes inflamed and starts to swell producing a sticky mucus or phlegm. All these reactions cause the airways to become narrower and irritated - leading to the symptoms of asthma which can include coughing, wheezing, getting short of breath and/or a tight feeling in the chest.
Atopic
People with a genetic predisposition to developing allergies and allergic diseases with a sensitivity to common inhalant allergens such as dust mites, cats and pollen or with a high total IgE level in their blood of more than 100kU/L.
Birch pollen
Birch is a common source of tree pollen allergens in Northern Europe and Scandinavia
Bronchial provocation test
An allergy test mostly used for research and always under close medical supervision in hospitals whereby the patient breathes in the suspect allergen and the reaction of the lungs are measured.
Basophils
A cell similar to mast cells involved in allergic reactions
Cat allergy
See Pet allergy
Coeliac disease
Approximately 1% of people suffer from Wheat Intolerance. Gluten found in wheat, rye, barley and oats cause the inflammatory condition of the gastrointestinal tract known as coeliac disease. This is not a true allergy but a food intolerance, in that the disease does not involve IgE antibodies. The gluten damages the surface of the small intestine which reduces its ability to absorb nutrients from food causing wasting and malnutrition. Coeliac disease can occur at any age and most coeliacs are diagnosed between the ages of 30 and 45 years old.
Condoms
Condoms and other products made from latex such as surgical gloves are a significant problem for many people with a latex allergy. Latex also cross-reacts with fruit such as bananas.
Contact dermatitis
Contact dermatitis is a different type of allergy that usually involves allergy cells rather than allergy antibodies. A frequent problem is "jeans button" allergy where a reaction occurs on the skin where the jeans button is in contact. Nickel found in fashion jewellery and buttons is a common trigger.
Cross-reactivity
Cross-reactivity is sometimes found between foods and pollens. For example, there is cross-reactivity between some tree pollens and apples -either of which could potentially trigger symptoms in a sensitized person.
Desensitisation
Desensitisation (immunotherapy) is a technique used to control allergies by administering a series of injections, sometimes over many years, containing the allergens to which the patient is sensitive to.
Dog allergy
See pet allergy
Drug allergy
Allergies to antibiotics such as penicillin can occur and may result in anaphylactic shock in those who are sensitive that receive penicillin.
Dust mites
Dust mites are one of the most common triggers of allergy symptoms - much more so than food allergies and intolerances. House dust is a complex mixture of fibers, minerals, dried food, moulds and microscopic spider like creatures called house dust mites. Dust mites live in nearly all homes and feed on flakes of human skin. They normally live unnoticed in warm and moist places such as bedding, sofas, curtains, carpets and children's furry toys - but if you have an allergy to them you may well notice the symptoms! Many people with asthma, eczema and rhinitis (hayfever) symptoms all year round are sensitive to the waste products of the house dust mites.
Dust mites can trigger symptoms all year round causing misery to anyone who is sensitive to them. Symptoms of asthma, eczema and rhinitis (hayfever) are commonly associated with dust mite sensitivity and may include itchy, runny or blocked nose and sneezing, itchy red, sore eyes, itchy sore throat and tongue rashes and eczema.
It is almost impossible to completely eliminate dust mites in your home. As a general guide if the amount of moisture (humidity) in the air in your home is high then so will be the level of house dust mites;
- reduce indoor humidity with a dehumidifier
- use a high filtration vacuum cleaner
- vacuum your mattress, carpets and soft furnishings at least once a week to remove mites
wash sheets, blankets, duvet covers and pillowcase regularly (A minimum 60°C is required to ensure dust mites and eggs are killed)
- damp dust all surface to stop the allergens becoming airborne
- keep your bedrooms well ventilated to prevent the build up of humidity
- air your mattress once per month if possible
- protective bedding can be purchased.
Early and late phase reactions
Allergic reactions have two phases (Biphasic) an early phase reaction which appears within minutes after inhalation or ingestion of an allergen involving IgE antibodies and a late phase which can occur many hours or even a day later caused by inflammatory mediators and the infiltration of inflammatory cells. These late phase symptoms may be more severe than the initial early phase reaction and can be confused with a food intolerance.
Eczema
Eczema (dermatitis) is a skin condition which can affects babies, children and adults. Approximately 20% of school aged children in the UK have eczema and about 8% of the adult population. The severity of eczema can vary from dry, hot and itchy areas of the skin to more severe forms where skin may become broken and bleed. Eczema flare-ups may be triggered by allergies and avoidance of the known allergy triggers, identified through allergy tests, may be a useful and drug free method to help control your symptoms.
Egg allergy
Egg Allergy is one of the most common food allergies. However, most affected are children under two years old. Egg allergy symptoms may include itching, swelling lips and face, coughing, shortness of breath and wheezing, asthma, dry, itchy throat and tongue, itchy skin, rashes and eczema, diarrhea, vomiting, headache or anaphylaxis.
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Food allergy
Food allergies are suffered by a million people in the UK. However, most affected are children under two years old. Food allergy symptoms may include; itching, swelling lips and face, coughing, shortness of breath and wheezing, asthma, dry, itchy throat and tongue, itchy skin, rashes and eczema, diarrhea, vomiting, headache or anaphylaxis
The most common foods that cause allergic reactions are; Milk, Eggs, Wheat/ gluten, citrus fruits, peanuts, walnuts, fish, shell fish and sesame seeds.
It is important that once you confirm you have a food allergy that you seek medical advice. You should not attempt to check your sensitivity by eating a food you suspect may be causing the problem. Similarly, avoidance of common foods such as milk, eggs or wheat should only take place after consultation with a dietician or your doctor as unnecessary avoidance of these foods can lead to nutritional deficiencies.
Food intolerance
Allergic reactions have two phases an early phase reaction which appears within minutes after inhalation or ingestion of an allergen and a late phase which can occur many hours or even a day later. These late phase symptoms may be more severe than the initial early phase reaction and can be confused with a food intolerance. Food intolerance can be caused by a wide range of triggers including true food allergies mediated by IgE antibodies. There are other types of food Intolerance, some of which are psychological such as a dislike of a particular foods texture or flavour. People with a wheat intolerance may in fact have coeliac disease - this is usually diagnosed by a taking a small sample of the intestine for study in the laboratory. Some people with intolerance's to dairy products may have a lactose intolerance. Lactose is a sugar found in milk. People with a specific deficiency of the enzyme lactase may have symptoms associated with lactose intolerance after they drink milk. The only tests for food intolerance commonly used in NHS hospitals in the UK are those for coeliac disease, lactose intolerance and tests that detect IgE antibodies such as RAST type tests.
Gluten allergy
See coeliac disease
Grass pollen allergies
Hayfever (grass pollen) is one of the most common allergic reactions and complaints in the UK. In general it starts between the ages of 8 and 20 years old, with the symptoms becoming less severe as the person gets older, but unfortunately there is no age limit on who can suffer.
Men are generally more susceptible than women. Surprisingly, it is more common in the city than in the countryside. There is evidence that suggests hayfever is increasing in prevalence along with other allergies. It is thought that pollution may be an important contributor. Hayfever symptoms can be experienced all year round, and may be confused with a cold. They can also trigger more severe conditions such as asthma, cough, wheezing and shortness of breath. Other allergy symptoms may include; frequent bouts of sneezing, runny, itchy or blocked nose, watery, itchy red or sore eyes, itchy sore throat and tongue, headache and loss of concentration.
Acting early in the season can mean you suffer fewer symptoms and suffer less misery. Avoid areas of long grass during the summer months, keep windows closed midmorning, late afternoon and early evening when the pollen counts are highest keep car windows closed when driving - check whether your car has a pollen filter and whether it needs replacing, wear glasses to reduce contact of pollen with the eyes, check pollen counts broadcast on the TV, radio or listed in newspapers before going out for the day and take avoidance action. Your pharmacist can advise on suitable medications which are available without prescription such as antihistamines, decongestants and anti-inflammatory nasal sprays and eye drops.
Hayfever
Pollen is released from different plants at different times of the year. Knowing when your symptoms occur can help you identify the likely trigger. Hayfever (grass pollen) is the most common seasonal sensitivity.
Tree pollens – Spring
Grass pollens (Hayfever) – Summer
Weed pollens – Autumn
House dust allergy
See Dust mites
House dust mites
See Dust mites
Hypoallergenic foods
Hypoallergenic foods have been processed by the food manufacturer to reduce the amount of allergens present.
Immunoglobulin E (IgE)
Immunoglobulin E (IgE) is the “allergy antibody” and is found at very low concentrations in the blood even in people with severe allergies. Allergy tests such as Imutest or RAST have to be very sensitive to accurately detect these small quantities of antibody.
Immunoglobulin G (IgG)
Immunoglobulin G (IgG) is the most common antibody found in the blood and is found at very high concentrations (about a million times more than IgE). IgG antibodies generally help people fight infections from viruses. Many healthy people have specific IgG antibodies that react with foods.
Immunotherapy
See Desensitisation
Imutest
Imutest is the worlds first allergy test designed to be used specifically as a self test at home. Imutest was invented by Dr John Rees, a British scientist who gained his PhD from St Bartholomew’s Medical School, London for research work on the allergens of the house dust mite. Imutest complies with the European IVD directive 98/79/EC and is CE accredited for self test use through British Standards Institution (BSi) and registered as a medical device with the UK Department of Health.
Inhalant allergens
Inhalant allergens are the most common allergy triggers of asthma, eczema and rhinitis (hayfever symptoms) such as dust mites, pollen and pet allergens. Moulds (fungus) also affect some people but are not so common.
Irritable bowel disease (IBS)
IBS is a chronic disease affecting about 20% of the population characterised by abdominal pain and intermittent diarrhea which often alternates with constipation. It is not known what causes IBS.
IVD
IVD stands for “In Vitro Diagnostic” test and are those tests usually carried out in a hospital laboratory on a sample of blood or urine. Imutest is a special type of IVD that has been specifically designed and shown to be safe and effective for self test use at home.
Lactose intolerance
Lactose intolerance is caused by the lack of a digestive enzyme (lactase) which breaks down lactose – the main sugar found in milk. Common symptoms can include nausea, stomach cramps and bloating and diarrhea which begin about 30 minutes to 2 hours after eating or drinking foods containing lactose.
Latex
Condoms and other products made from latex such as surgical gloves cause a significant allergy problem for many people. There is also cross-reactivity between latex allergens and fruits such as bananas
Mast cells
These are cells of the immune system that are a key component of the allergic process. If a person is sensitive to allergies such as pollen, the IgE antibodies become bound to the surface of the mast cells. When the person is again exposed to pollen these allergens bind to the IgE antibodies – this causes the mast cells to release chemicals such as histamine into the tissues triggering the clinical effect of an allergic reaction.
Milk
Cows milk allergy is one of the most common food allergies. However, most affected are children under two years old. Milk allergy symptoms may include; itching, swelling lips and face, coughing, shortness of breath and wheezing, asthma, dry, itchy throat and tongue, itchy skin, rashes and eczema, diarrhea, vomiting, headache or anaphylaxis. Another form of milk allergy is lactose intolerance (lactose intolerance can not be detected by skin prick test, Imutest, RAST or food IgG intolerance tests) see Lactose intolerance for further information
Moulds
Moulds are associated with damp indoor conditions and can trigger allergies in some people but are not as common as sensitivity to dust mites, pollen or pets. Outdoor moulds may cause “hay fever” like symptoms in autumn.
Patch tests
Patch tests are usually used to identify a sensitivity causing contact dermatitis.
Perennial allergens
Perennial allergens are inhalant allergens present all year round. These would include dust mites and pet allergens
Pet allergy
Up to 10% of the population may be allergic to pet animals to some degree - for those with asthma this rises to almost 30%! Up to 40% of children with asthma are allergic to cats.
- cats are the most common cause of pet allergy
- dogs are the second most common cause
The cat allergens are present in the skin scales, saliva, sweat glands and tears of the cat but it is distributed over the fur during grooming. The saliva dries on the cat hair and becomes airborne. In dogs the allergen is found mainly in the skin scales and the saliva. Small animals such as mice, rats and guinea pigs also have allergens in their urine and is also found in dust from their litter.
Pets can trigger asthma leading to cough, wheezing, tightness in the chest and shortness of breath. Pets can also be the cause of rashes and eczema. Other allergy symptoms may include;
- itchy, runny or blocked nose and sneezing
- itchy red, sore eyes
- itchy sore throat and tongue
Treatment and avoidance measures;
- don’t keep furry pets - however, if you can’t bare parting with your pet then try to limit them to one room in the house
- keep your pet out of the bedroom and off any furniture in a room where you spend most of your time, as exposure can be very high
- don’t let your pet near your face or clothing as this can exacerbate your symptoms
- wash your pet regularly - allergens can be easily washed away with a wet sponge (wear gloves when washing your pets or better still get someone else to do it or you)
- ask someone else to brush your pet to remove allergens from the fur or hair- preferably outside the house!
- vacuum carpets and soft furnishings regularly to remove animal hairs
- replace bedding that pets have been in contact with regularly - it can take months or even years to remove allergens from fabrics
- consider installing an air cleaner
If you are visiting the home of a pet owner then request that they do not vacuum clean immediately before your visit as the pet allergens can remain airborne for up to a day making the allergens more likely to be breathed in. There is also evidence that allergen levels can be 200% higher in homes with poor ventilation.
Plasma
This is the liquid component of the blood that contains antibodies.
Pollen
See Grass pollen
Provocation test
See Bronchial provocation test
Prick test
See Skin prick test
RAST (Radio-allergosorbent test)
The RAST test has been used in NHS hospital laboratories since the 1960s. The test originally required radioactive isotopes of Iodine to detect specific and total IgE antibodies. The original test could take up to a week to get a result. Imutest uses the same technology (but without the radioactive iodine!) to detect the IgE but gives accurate results in about 30 minutes.
Rhinitis
Rhinitis for most people means runny eyes or a runny or blocked nose and is a frequent symptom of hay fever. We all sympathise with the misery that the common cold can cause for a few days. However, some people with perennial rhinitis caused by a dust mite allergy may suffer from a “permanent cold” all year round. Identifying and eliminating the allergy trigger has obvious benefits for the rhinitis sufferer.
Seasonal allergens
Seasonal allergies such as hayfever affect people just at certain times of the year when high levels of the allergen are present e.g. Grass pollen.
Serum
Serum is similar to plasma but has had the clotting components removed. Serum also contains the allergy antibodies and is often used in laboratory allergy tests.
Skin prick test
The skin prick test is the most common type of allergy test and gives similar results to blood tests such as Imutest or RAST. The skin prick test works by the doctor applying a drop of allergen extract on the skin (usually the forearm or back). The drop is then pricked through to scratch the skin surface. If the person has a sensitivity to a specific allergen then a small bump surrounded by a red, itchy area will appear in about 15 to 30 minutes. The skin prick test is very sensitive but can cause false positive reactions in some people with dermatographism. The test may not be suitable for people with eczema or other skin diseases and people who are at risk from a severe reaction. The skin prick test may also suffer from false negative results in patients taking antihistamine medicines (these medicines don’t interfere with blood tests such as Imutest or RAST).
Specific IgE
Specific IgE means IgE antibodies that specifically react only with one type of allergen. For example pollen specific IgE antibodies will not react with dust mite allergens.
Steroids
These are a group of medicines frequently prescribed to allergy sufferers and have been very successful at controlling asthma, eczema and rhinitis. The medicines have been proven to be a safe way to reduce the frequency and severity of symptoms.
Total IgE
This is a measure of all the IgE antibodies irrespective of which allergens they react with (compare with Specific IgE). Total IgE is detected with the Imutest Allergy Check test and is a general indicator of the risk of allergy. The average level of IgE in healthy people is around 13kU/L although levels of 5000kU/L or more can be found in some people with allergy related diseases such as eczema. It is unusual to find specific IgE sensitivity or clinical allergy in people with less than 20kU/L of total IgE in their blood. Similarly, people with more than 100kU/L of total IgE are highly likely to have specific sensitivities and clinical allergy symptoms.
Tree pollen allergy
Hayfever symptoms due to an allergy to tree pollens can occur in spring when trees release their pollen into the air. Symptoms are similar to grass pollen sensitivity. People with sensitivity to tree pollens may also have food sensitivities to fruit such as apple.
Urticaria
An itchy rash also known as nettle rash or hives.
Weal
A raised bump in the skin either as an urticaria or as part of a skin prick test reaction.
Wheat allergy
Wheat allergy, where IgE antibodies can be detected to wheat proteins is different from wheat intolerance (see coeliac disease). Occupational asthma such as bakers asthma may be attributed to a true IgE allergy where wheat specific IgE antibodies can be found in the blood of people that may be exposed to flour dust.
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