| There are 20 million people in the UK | | | | time. |
| who are suffering with an allergy at any | | | | How is food allergy and food intolerance |
| one time; of these, the numbers who are | | | | diagnosed? |
| diagnosed with a food allergy is rising | | | | The key to diagnosis is a careful |
| faster than for any other allergy. With | | | | allergy history taken by an allergy |
| this in mind, STH Online went to speak | | | | specialist. Blood and skin tests are |
| to Fran Ashworth, Senior Clinical | | | | used to provide additional evidence, but |
| Immunology and Allergy Nurse Specialist, | | | | are never used alone to diagnose allergy |
| to find out more. | | | | as they can be positive without allergy |
| What is food allergy and food | | | | and vice versa. |
| intolerance? | | | | A skin-prick test is a quick and easy |
| A food allergy is an allergic reaction | | | | way of identifying whether an antibody |
| to something that is eaten. Food allergy | | | | is present and involves introducing a |
| is caused when the body mistakes the | | | | small amount of the suspected food to |
| proteins in food as a dangerous | | | | the skin, then pricking through with a |
| substance and produces antibodies to | | | | lancet or scalpel. If the patient is |
| fight it, which causes a reaction to | | | | sensitised the skin will become itchy |
| that particular food. When the food is | | | | within a few minutes, then red and |
| eaten, the immune system releases | | | | swollen. |
| chemicals such as histamines, which | | | | If the skin-prick test cannot be done |
| cause various symptoms including asthma, | | | | for any reason, a test to detect the IgE |
| rashes and swellings, hay-fever, | | | | antibody in the blood can be used |
| vomiting, tummy pain, and in the most | | | | instead. |
| severe cases can cause anaphylaxis (a | | | | Challenge tests and exclusion diets are |
| severe allergic reaction causing | | | | used in some cases where the diagnosis |
| collapse, with breathing difficulties or | | | | remains uncertain. Challenge tests are |
| low blood pressure). | | | | potentially dangerous in food allergy |
| Food intolerance is much more common | | | | patients and should therefore only ever |
| than food allergy and describes any | | | | be undertaken in a specialist hospital |
| adverse reaction to food that does not | | | | centre with appropriate experience, such |
| involve the immune system. Food | | | | as in the Clinical Immunology and |
| intolerance is very unpleasant but | | | | Allergy Unit at the Northern General |
| rarely dangerous. | | | | Hospital. |
| Food intolerance has a number of | | | | There is no reliable blood test or skin |
| different causes and not all are known. | | | | test that can confirm or deny food |
| Some reactions are a predictable result | | | | intolerance and patients rely on an |
| of natural substances in the food, which | | | | elimination and challenge diet and the |
| cause adverse symptoms if you eat a | | | | symptom history for diagnosis. Patients |
| large enough dose, or if you are more | | | | often purchase non-standard tests of |
| susceptible to the effects for some | | | | doubtful validity from private |
| reason, such as lacking an enzyme needed | | | | providers, which may be of little help |
| to tolerate the food (examples would be | | | | when diagnosing food intolerance. |
| food-induced migraines or lactose | | | | How can I prevent food allergy and food |
| intolerance). Coeliac disease is an | | | | intolerance? |
| immunological reaction to wheat gluten, | | | | There is no evidence that development of |
| but is a different type of allergy, but | | | | food intolerance can be usefully |
| should be excluded in patients with | | | | prevented by dietary modification in |
| symptoms related to wheat or cereals. | | | | children. |
| There are a number of foods that contain | | | | Nevertheless, breast feeding is thought |
| naturally occurring toxins, which also | | | | to be very beneficial; weaning advice is |
| result in adverse reactions if enough of | | | | important but there is no clear evidence |
| the food is eaten. Whilst chemical and | | | | that this prevents the development of |
| food additives are often suspected as a | | | | allergy. Solid foods should be delayed |
| cause, there is little evidence that | | | | until six months and restricted to lamb, |
| symptoms of intolerance are directly due | | | | meat, chicken, rice, sweet potatoes, |
| to these substances, except in a few | | | | carrots and pears. Milk, eggs, wheat, |
| cases, eg an excess of monosodium | | | | fish, soya and citrus foods should be |
| glutamate (a food additive). | | | | avoided for the first year and nuts and |
| Food intolerance often varies throughout | | | | peanuts for the first three years. |
| a person's lifetime and patients can | | | | Children often have an intolerance of |
| sometimes tolerate a small amount of the | | | | cow's milk proteins which cause |
| food in question. | | | | diarrhoea and colic; this is actually a |
| What foods are affected? | | | | different type of allergy and usually |
| Any food can cause an allergy, but there | | | | resolves as the child grows, but |
| are some that are more common than | | | | requires avoidance of milk proteins for |
| others; these include milk, eggs, wheat, | | | | a prolonged period. |
| nuts, soybeans, peanuts, fruits, | | | | What kind of treatment is available? |
| vegetables and seafood. | | | | There are a variety of treatments |
| The most common foods which cause | | | | available for patients suffering with |
| intolerance are milk, eggs, nuts, | | | | food allergy, although at present there |
| seafood, wheat, flour, chocolate, | | | | is no cure. Allergic adults should |
| artificial colours, pork, bacon, | | | | completely avoid the food they are |
| chicken, tomato, soft fruit, cheese and | | | | allergic to for the rest of their lives |
| yeast, but any food can cause an | | | | in most cases. Children with common food |
| intolerance, which can appear at any | | | | allergies, such as to egg, may lose the |
| time in your life. | | | | allergy as they get older. |
| Is food allergy and food intolerance | | | | An EpiPenTM is an auto-injector that |
| common? | | | | contains Epinephrine (Adrenalin), which |
| Up to 20% of the population have adverse | | | | can be used as an emergency treatment |
| reactions to food and most suffer food | | | | for patients suffering anaphylaxis or |
| intolerance, but only approximately 1% | | | | other serious allergic reactions; |
| of adults and 2-4% of children are truly | | | | steroids or anti-histamines may also be |
| food allergic. | | | | given. |
| Who is at risk? | | | | Some patients who experience severe |
| A tendency to allergies (Atopy) often | | | | allergic reactions choose to wear |
| runs in families and patients are | | | | medical alert jewellery in the form of a |
| therefore at an increased risk of having | | | | necklace or bracelet to alert others of |
| a food allergy if their mother or father | | | | their food allergy or food intolerance, |
| or a sibling has an allergy. | | | | whilst many choose to carry an |
| What are the common symptoms? | | | | information card as an alternative. |
| Patients suffering allergic reactions to | | | | At present there is also no cure for |
| food can experience symptoms such as | | | | food intolerance. The best treatment |
| abdominal pain or bloating, vomiting and | | | | again is to avoid the foods that cause |
| diarrhoea, runny nose, sneezing, | | | | problems and to carry any emergency |
| wheezing or a cough, itching, swelling | | | | treatment you have been prescribed. |
| or rash, body swelling, breathing | | | | Patients need full training and |
| difficulties, and in more extreme cases | | | | education in food avoidance and the use |
| anaphylaxis. Symptoms usually occur | | | | of their medication, as it is well known |
| within 20 minutes and very rarely can be | | | | that if this is not done patients may |
| delayed for a couple of hours. | | | | forget to continue best practice. |
| Food intolerance can cause fatigue, | | | | What is STH doing to help food allergy |
| bloating, irritable bowel, joint pains, | | | | and food intolerance patients? |
| rashes, flushing, abdominal pain, | | | | The Clinical Immunology and Allergy Unit |
| eczema, vomiting and diarrhoea, | | | | at the Northern General Hospital |
| palpitations and migraine. The onset of | | | | provides a full range of education, |
| symptoms is very variable. Symptoms can | | | | support and training in the management |
| last for many hours and in some cases, | | | | of allergic disease and intolerances, |
| well into the next day. Patients with | | | | including written treatment plans, |
| intolerance to gluten or wheat may have | | | | challenge tests for diagnosis and a |
| coeliac disease (a different type of | | | | specialist allergy dietician service. |
| allergy to gluten in cereals) which will | | | | Where can I find out more? |
| need to be excluded. | | | | If you feel you may be suffering from |
| A patient suffering a food allergy will | | | | food allergy or food intolerance you |
| generally experience a more limited | | | | should visit your GP, who may refer you |
| range of symptoms than patients | | | | to the Clinical Immunology and Allergy |
| experiencing food intolerance, who often | | | | Unit for further investigation, if this |
| suffer multiple symptoms at the same | | | | is deemed appropriate |