Hay fever (seasonal allergic rhinitis)
 
Sneezing, a blocked or runny nose and itchy eyes are common symptoms of hay fever, also called seasonal allergic rhinitis. Like other allergic conditions such as eczema, it seems to be becoming more common, especially in children.

What is hay fever?

Hay fever is an allergic reaction to pollen. Pollen is an allergen, the term given to any substance that can cause an allergic reaction. Your allergic reaction happens when your body´s immune system mistakes the allergen for a harmful invader. Most people are not sensitive to allergens.

Allergens such as grass and tree pollens cause seasonal allergic rhinitis (hay fever).

Other allergens, such as house-dust mites, cat or dog hair and moulds, never disappear, and cause year-round symptoms. This condition is known as perennial allergic rhinitis.

Hay fever, asthma and eczema are all related allergic conditions and the tendency to develop them runs in families. This tendency is called atopy. People with hay fever often have a close relative with one or more of these conditions.

What happens when you get hay fever?

When you come into contact with pollen, your body produces increased amounts of a type of antibody called immunoglobulin E (IgE). Antibodies are usually produced by the body to fight infection. But if you have hay fever, your body produces antibodies in response to pollen.

The increase in IgE causes certain cells throughout the body, especially those of the respiratory (breathing) system, to release chemicals such as histamine. It is histamine that triggers the symptoms of sneezing, a stuffy nose and itchy eyes and throat.
 
Hay fever can make asthma worse and some people who are not usually asthmatic may become wheezy during the hay fever season.

How do I know if I am allergic to pollen?

Your doctor will usually be able to tell if you have hay fever by asking about your symptoms and when you get them. He or she may look inside your nose and down your throat to make sure you don´t have any other problems that could be causing your symptoms.

Your doctor may also advise that you have a skin-prick allergy test to help determine if you have an allergy to pollen and if so, which pollen is causing it.

The test will check your reaction to tiny amounts of pollens found where you live. A small needle will be used to prick a drop of fluid containing a known type of pollen, just under the surface of your skin, usually on the inner forearm.

If you are allergic, you may get a small bump around where the test was done (called a weal). The skin around the bump may also turn red. If these things happen, you´ve had a positive reaction.

These tests are not always reliable however. For example, your skin may not react to the pollen that´s causing your hay fever. Or your skin may react to something that doesn´t cause hay fever.

Your doctor may also advise that you have a blood test to measure the amount of IgE antibodies in your blood. The level of IgE can tell your doctor how bad your allergy is.

Pollen season

A person with hay fever may be allergic to one, several or many types of pollen. Most people with hay fever are allergic to air-borne grass pollens however.

Most people suffer only a few weeks of mild discomfort, but for an unlucky few, the symptoms can be severe and last for months.

Preventing hay fever

Once you have discovered what you are allergic to, the first step in minimising your symptoms is to avoid those triggers as much as possible:
 
 l close doors and windows (including car windows and sunroofs) when the pollen season starts
 l avoid pollen-rich areas, particularly in the afternoon and evening when the pollen released in air is high
 l wear wrap-around close-fitting sunglasses to keep pollen out of your eyes
 l take a shower and wash your hair after going outside when the pollen count is likely to be high

Treatment

Even if you take all the steps you can to avoid the allergens you are sensitive to, you can´t normally avoid them altogether. There is a wide range of treatments available - you may need to use a combination of these to control your hay fever symptoms. Many treatments are available over the counter from pharmacists (without prescription) and your pharmacist will be able to provide advice about products suitable for you.

Nose sprays and drops can help control stuffiness and sneezing. They include steroids and antihistamine. Steroid-based nasal sprays can take a week before they are fully effective so it is a good idea to start taking these before your symptoms usually start.

Eyedrops help to ease itchy eyes. The range of drops on offer includes those that contain the medicine sodium cromoglicate. Antihistamine eyedrops are also effective.

Tablets such as antihistamine tablets can be helpful for itchy eyes, but many people find they can´t do without nose drops or sprays as well. Some people get drowsy when they take older-style antihistamines. Newer, non-sedating types, generally cause less drowsiness, although they tend to be more expensive. Tablets containing antihistamines and a decongestant are also effective.

Treating severe hay fever

If you have severe hay fever, over-the-counter medicines may not be enough to deal with the symptoms. Or sometimes, you may need fast relief (for example, if you have to sit an exam). In these cases, you may need a prescription-only steroid medicine.

Steroids come as tablets or injections. A single injection of a long-acting steroid can bring symptoms under control quickly. However, there have been significant concerns about irreversible side-effects. For example, long-term use of steroids can lead to osteoporosis or weaken the immune system.

Most doctors now prefer to prescribe a short course of steroid tablets, where necessary. Other treatments such as nasal sprays can be used at the same time.

Immunotherapy

If you cannot find a treatment that can control your hay fever symptoms, immunotherapy may be an option. This involves exposing you to regular, controlled amounts of pollen. You will be given a series of allergen injections or course of tablets that are dissolved under the tongue, with a gradually increasing dose. Although the process by which the treatment works is not known exactly, it can be a successful treatment and can make you less sensitive to pollen.

Early immunotherapy treatments had side-effects and became unpopular. However, there are newer immunotherapy preparations, which do not have the same side-effects, and more promising treatments. More research is needed to determine how beneficial immunotherapy will be for hay fever.