How are allergies diagnosed?
Often people can self-diagnose and manage a simple allergy, such as hay fever.
But if this doesn't help or the symptoms are serious then it is important to see a GP, who will take a history and conduct any relevant physical examination. If they can't diagnose your condition they will refer you to an allergy specialist or immunologist.
To help determine the allergen a doctor will ask what happened prior to symptoms occurring. Sometimes the allergen is obvious, as in many cases of asthma or hay fever – a person may start sneezing or wheezing every time they come near a horse, for example.
But in other cases, food allergies or eczema, for example, it's not so obvious if it's an allergy or what the allergen is.
It's possible to identify an allergen by testing.
Skin prick testing involves introducing a tiny amount of a potential allergic trigger into the skin. If the person is allergic to one or more allergens then they will have a characteristic reaction – the area around the injection site will become red and raised.
Blood tests are needed when people have eczema, anaphylaxis (specialists will not want to expose these people to their allergen), cannot come off antihistamines (antihistamines affect the accuracy of skin tests) or have a history of allergic symptoms but test negative with skin prick testing.
If you have contact dermatitis your doctor may do patch tests, for more information about this read our fact file on eczema and dermatitis.
But be careful; there are a lot of allergy tests on the market such as cytotoxic food testing, kinesiology, Vega testing, electrodermal testing, pulse testing, reflexology and hair analysis that are not scientifically proven.
How are allergies treated?
The best way to deal with an allergy is to avoid what triggers it. No exposure to the allergen; no allergic response.
In some cases it's easy. If you're allergic to cats, avoid cats.
But sometimes it's not so easy. People may not know what they are allergic to, or it might be impossible to avoid the allergen, for example pollen during spring. In these situations treating the symptoms is the best option. Taking medications will help relieve the symptoms or 'dampen down' the allergic reaction.
Symptomatic treatments include antihistamines (taken in a nasal spray, eye drops or tablet), corticosteroids (in nasal sprays, puffers, skin creams and ointments, but not normally as tablets), bronchodilators (drugs that expand the airways given by puffer). If you have anaphylaxis you'll need to carry adrenaline with you all the time in case you have a severe reaction.
Some of these medications may have side effects, for example taking antihistamines orally can cause drowsiness.
Providing the allergen is known another option is to 'desensitise' the immune system to the particular allergen. This process is called immunotherapy and involves exposing a person to increasing doses of an allergen over time. This is typically done via injections or high doses of oral extracts placed under the tongue.
The idea is the immune system becomes used to the allergen and no longer provokes an allergic response.
Immunotherapy can be expensive and time consuming (it may take months or even years) and often doesn't work, or works only temporarily – eg for one spring/summer season – so you need to weigh up whether it's worth it. It tends to work best for asthma and rhinitis and people with severe allergy to insect stings. It is a form of therapy used when people have bad allergies when medicines don't work or as an alternative to medication. Besides, many allergies last for years and the cost of medicines can also add up. Unfortunately it does not yet help food allergy, but this is an active area of research.
Managing your allergy
Most people manage their allergies through a combination of avoiding their known allergens where possible and using treatments to relieve the symptoms. While not the ideal solution it can help most people manage to get their symptoms under reasonable control.
There is no way of curing an allergy but there are things you can do to reduce the risk of having an allergic reaction, these include:
Breastfeed your infant for the first 4 – 6 months if possible – infants who are breastfed have fewer allergies.
Don't smoke during pregnancy or in the presence of a child.
Develop an action plan to manage your or your child's allergy. An action plan can help people manage their allergies such as what medications to take and when and what to do in the event of a medical emergency. Most people diagnosed with asthma or anaphylaxis will be given an action plan by their doctor.
Educate your friends, family, school staff and community about your allergy (or your child's allergy). They play a vital role in helping avoid allergy triggers and can get help in an emergency.