Allergies and hayfever

What is an allergy?

Some allergic reactions are mild and harmless, but others are severe and potentially life-threatening (anaphylaxis). Fortunately these very severe allergic reactions are quite rare and you would be extremely unlucky to develop one. Some people have allergic reactions to simple things like dust, pollen, pet hair or food (i.e. peanuts)

How common are allergies?

Allergies are very common. About 1 in 4 people in Ireland are affected by an allergy at some time during their life. Each year the number of affected people increases.

Who gets allergies?

Anyone can have an allergy and about half of people with persistent allergies are children. Some people are much more prone to allergic problems and are predisposed to allergic reactions. This condition is normally referred to as atopy, and can often run in families. Food is a common trigger in children whilst, in older people, medicines are common culprits. People in atopic families can develop problems such as asthma, eczema and hay fever. It is an inherited problem and these people are more likely to develop an allergic disorder.

What are the symptoms of an allergy?

Allergic reactions can vary and may include a number of different symptoms. In most cases the symptoms are mild and irritating to those affected, whilst in other less frequent cases the symptoms are more severe. Some possible of the possible symptoms are listed below:

• Rhinitis (inflammation of the nose). This causes runny nose or nasal congestion and sneezing.
• Conjunctivitis (inflammation of the eyes). This leads to watering, itching and a hot feeling in the eyes.
• Skin rashes. The typical allergic rash is an urticarial rash – also known as hives or nettle rash. It is very itchy. Flushing of the skin is also common.
• Angio-oedema. This is swelling of the tissues, and can include the lips, tongue, throat and eyelids. It can start with a tingling feeling. Angio-oedema is potentially very serious, as airway obstruction can occur (and so breathing might stop). People might have difficulty talking or swallowing.
• Breathing difficulties. This includes wheezing, chest tightness and breathlessness, and can occur in severe allergic reactions and anaphylaxis. It can be life-threatening.
• Cardiovascular collapse. This is extremely rare but it can cause death. It is the end stage of anaphylaxis. The chemicals released by the body in an extreme allergic reaction can make blood pressure drop dramatically. This can lead to loss of consciousness and to cardiac arrest (the heart stops). Resuscitation is required.
• Other symptoms. These can include a sense of general panic, abdominal pain, nausea and vomiting, and palpitations.

Common allergens

Things that people are commonly allergic to include:

• Tree and grass pollens.
• House dust mite.
• Animals, especially domestic pets such as cats and dogs.
• Insect venom such as that contained in wasp and bee stings.
• Medicines – for example, the antibiotic penicillin.
• Foods, such as nuts and eggs.
• Chemicals such as latex.

Anaphylaxis

Anaphylaxis is the medical term for an uncommon but very severe allergic reaction. It can affect the whole body and can be life-threatening. As such it is therefore considered a medical emergency. If you suspect someone has anaphylaxis, you should dial 999 for an ambulance.

The symptoms of anaphylaxis may include:

• Breathing problems and angio-oedema.
• Collapse and loss of consciousness.

Treatment of allergies

Avoidance of the cause

Treatment with medication often works so well that you may not have much motivation or need to avoid the cause of the allergy. However, some people may wish to try to avoid the cause of the allergy, particularly if medication is not fully effective. There are a number of measures you can take to reduce the amount of common aero-allergens (those found in the air). For instance, in the case of hay-fever, particularly in warm weather this can include taking simple measures such as keeping bedroom windows closed when sleeping, wearing sun glasses when out walking, and avoiding freshly cut grass. Rinsing the eyes and nose with a saline rinse after being outdoors can sometimes also be effective.

Medication

Treatment with nose sprays, eye drops and/or antihistamine tablets will often ease or clear the symptoms. These medicines normally aim to reduce the allergic response of the body and therefore ease the symptoms. It is also common that a combination of medicines (i.e. eye drops and antihistamine tablets) are best at controlling symptoms when numerous parts of the body are affected (such as in the case of hay-fever). In addition it is common that trial and error is needed in finding the best course of treatment for sufferers. Often patients need to try and variety of solutions before they find the best option that works best for them. Many of these very effective allergy treatments are available over the counter from your pharmacist without prescription.