Allergy Types: Other Allergies: Hay Fever
Allergic rhinitis is an allergic inflammation of the nasal airways. It occurs when an allergen, such as pollen, dust, or animal dander(particles of shed skin and hair) is inhaled by an individual with a sensitized immune system. In such individuals, the allergen triggers the production of the antibody immunoglobulin E (IgE), which binds to mast cells and basophils containing histamine. When caused by pollens of any plants, it is called pollinosis, and, if specifically caused by grass or tree pollens, it is known as hay fever. While symptoms resembling a cold or flu can be produced by an allergic reaction to pollen from plants and grasses it does not cause a fever. The link with hay came about due to an early (and incorrect) theory that the symptoms were brought about by the smell of new hay (coumarin). A competing popular name was ‘hay asthma’.
IgE bound to mast cells are stimulated by allergens, causing the release of inflammatory mediators such as histamine (and other chemicals). This causes sneezing, itchy and watery eyes, swelling and inflammation of the nasal passages, severe respiratory difficulties, inflammation of the skin, extremely irrititated eyes, and an increase in mucus production. Symptoms vary in severity between individuals. Very sensitive individuals can experience hives or other rashes. Particulate matter in polluted air, and chemicals such as chlorine and detergents, which can normally be tolerated, can greatly aggravate allergic rhinitis. The first accurate description of hay fever was completed by the 10th century physician Rhazes in his manuscript “A Dissertation on the Causes of the Coryza which Occurs in the Spring When the Roses Give Forth Their Scent.” The true agent causing hay fever was finally identified as pollen in 1859 by Charles Blackley, who concluded that pollen contained toxins leading to the reaction. It was not until 1906 that the mechanisms of allergy as a type of hypersensitivity were understood following the work of Clemens von Pirquet.
Allergies are common. Heredity and environmental exposures may contribute to a predisposition to allergies. It is roughly estimated that one in three people has an active allergy at any given time and at least three in four people develop an allergic reaction at least once in their lives. In Western countries, between 10–25% of people annually are affected by allergic rhinitis.
Allergic rhinitis triggered by the pollens of specific seasonal plants is commonly known as “hay fever”, because it is most prevalent during haying season. However, it is possible to suffer from allergic rhinitis throughout the year. The pollen that causes hay fever varies between individuals and from region to region; in general, the tiny, hardly visible pollens ofwind-pollinated plants are the predominant cause. Pollens of insect-pollinated plants are too large to remain airborne and pose no risk. Examples of plants commonly responsible for hay fever include:
- Trees: such as pine (Pinus), birch (Betula), alder (Alnus), cedar, hazel (Corylus), hornbeam (Carpinus), horse chestnut (Aesculus), willow (Salix), poplar (Populus), plane (Platanus), linden/lime (Tilia), and olive (Olea). In northern latitudes, birch is considered to be the most common allergenic tree pollen, with an estimated 15–20% of hay fever sufferers sensitive to birch pollen grains. A major antigen in these is a protein called Bet V I. Olive pollen is most predominant in Mediterranean regions. Hay fever in Japan is caused primarily by sugi (Cryptomeria japonica) and hinoki (Chamaecyparis obtusa) tree pollen.
- “Allergy friendly” trees include: ash (female only), red maple, yellow poplar, dogwood, magnolia, double-flowered cherry, fir, spruce, and flowering plum.
- Grasses (Family Poaceae): especially ryegrass (Lolium sp.) and timothy (Phleum pratense). An estimated 90% of hay fever sufferers are allergic to grass pollen.
- Weeds: ragweed (Ambrosia), plantain (Plantago), nettle/parietaria (Urticaceae), mugwort (Artemisia Vulgaris), Fat hen (Chenopodium), and sorrel/dock (Rumex)
Allergic rhinitis may also be caused by allergy to Balsam of Peru, which is in various fragrances and other products.
A risk factor is something that increases a person’s chances of developing a disease or condition. Below are some risk factors for hay fever:
- Family history (inheritance, genetics) – if you have a close family member who has/had hay fever, your risk of developing it yourself is higher. There is also a slightly higher risk if a close family member has any type of allergy.
- Other allergies – people with other allergies are more likely to suffer from hay fever as well.
- Asthma – a significant number of people with asthma also have hay fever.
- Gender and age – hay fever affects more young males than young females. Before adolescence, twice as many boys as girls have hay fever. However, after adolescence many boys outgrow it and slightly more girls than boys are affected.
- Birth date – people born during the high pollen season have a slightly higher risk of developing hay fever than other people.
- Second-hand smoke – infants and babies who are regularly exposed to cigarette smoke during their first years of life are more likely to develop hay fever than babies who aren’t.
- Being the first child – a higher percentage of firstborn children eventually develop hay fever, compared to other people.
- Babies from smaller families – a higher proportion of babies with no siblings, or just one sibling develop hay fever later on compared to babies born to larger families.
- Babies born to high income families – babies born to families with a high standard of living have a higher risk of developing hay fever later on, compared to other babies.
Experts believe that the last three risk factors are linked to childhood infections. If a baby and/or small child has had fewer infections, there is a greater risk of autoimmune problems.
Allergy testing may reveal the specific allergens to which an individual is sensitive. Skin testing is the most common method of allergy testing. This may include a patch test to determine if a particular substance is causing the rhinitis, or an intradermal, scratch, or other test. Less commonly, the suspected allergen is dissolved and dropped onto the lower eyelid as a means of testing for allergies. This test should be done only by a physician, never the patient, since it can be harmful if done improperly. In some individuals not able to undergo skin testing (as determined by the doctor), the RAST blood test may be helpful in determining specific allergen sensitivity. Peripheral eosinophilia can be seen in differential leukocyte count.
Allergy testing can either show allergies that are not actually causing symptoms or miss allergies that do cause symptoms. The intradermal allergy test is more sensitive than the skin prick test but is more often positive in people that do not have symptoms to that allergen.
Even if a person has negative skin-prick, intradermal and blood tests for allergies, he/she may still have allergic rhinitis, from a local allergy in the nose. This is called local allergic rhinitis. Specialized testing is necessary to diagnose local allergic rhinitis.
There is a vast array of OTC (over-the-counter) and prescription medications for treating hay fever symptoms. Some patients may find that a combination of two or three medications works much better than just one.
It is important for parents to remember that some hay fever medications are just for adults. If you are not sure, talk to a qualified pharmacist, or ask your doctor.
Nasal sprays can offer effective relief for hay fever
- Antihistamine sprays or tablets – these are commonly available over the counter. The medication stops the release of the chemical histamine. They usually effectively relieve symptoms of runny nose, itching and sneezing. However, if your nose is blocked they don’t work.
Newer antihistamines are less likely to cause drowsiness than older ones – but older ones are just as effective. Examples of OTC antihistamines include loratadine (Claritin, Alavert) and cetirizine (Zyrtec). Examples of prescription antihistamines include Fexofenadine (Allegra) and the nasal spray azelastine (Astelin). Azelastine starts working very rapidly and can be used up to 8 times a day – however, it can cause drowsiness and leave a bad taste in the mouth after use.
- Eye Drops – these reduce itching and swelling in the eyes and are usually used alongside other medications. Eye drops containing cromoglycate are commonly used.
- Nasal Corticosteroids – These sprays treat theinflammation caused by hay fever, and are a safe and very effective long-term treatment. Examples include fluticasone (Flonase), fluticasone (Veramyst), mometasone (Nasonex) and beclomethasone (Beconase). Most patients may have to wait about a week before experiencing any significant benefits. Some patients may notice an unpleasant smell or taste, and have nose irritation.
- Oral corticosteroids – for very severe hay fever symptoms the doctor may prescribe prednisone in pill form. They should be prescribed only for short-term use, because of their long-term link to cataracts, muscle weakness and osteoporosis.
- Desensitization treatment (immunotherapy) – this treatment used to be more common in the UK, but is now very rarely used and is not used at all in the USA, because it can cause some very strong reactions. Increasing amounts of the allergen are introduced into the patient. This treatment is only done in very specialized centers for patients with severe symptoms.
- Alternative therapies – some alternative therapies claim to treat hay fever effectively.
A study published in The Medical Journal of Australia carried out by researchers at the University of Melbourne, suggested that acupuncture is effective in the symptomatic treatment of persistent allergic rhinitis. (MJA 2007; 187 (6): 337-341)/
- It is important to remember that although some patients do report benefits from alternative therapies, a lot of information one reads in books and on the internet is anecdotal. For therapy to be convincing, it should undergo proper clinical tests which are either compared to a placebo (dummy treatment) or some treatment known to be effective. Before undergoing any complementary/alternative therapy, check it out carefully.
Pregnancy – decongestants and birth defects – researchers at Boston University reported in the American Journal of Epidemiology that pregnant mothers who take over-the-counter decongestants during their first trimester may have a higher risk of giving birth to babies with rare defects in their digestive tract, ear and heart.
Hay fever affects around one in four people in the UK. Maureen Jenkins, Clinical Director of Allergy UK, offers some tips on avoiding the causes and reducing your symptoms.
“The main triggers of hay fever are tree and grass pollen,” says Maureen. “Pollen from weeds and shrubs can also trigger symptoms. The pollen count is always higher on hot, dry days. Fungal spores are around on most mild damp days, but are particularly high after harvesting and in the autumn.”
The following tips can help you avoid pollen and lessen the chances of hay fever.
Don’t mow your lawn
Ideally, if grass makes you sneeze, ask someone else to mow your lawn when the pollen count is high. “If you react to grass and you spend time on the lawn, you’ll get breathing symptoms and often also hives,” says Maureen.
Create a barrier
Smear a nasal barrier balm inside your nostrils, or use a drug-free nasal spray or dab of petroleum jelly (such as Vaseline) to prevent pollen sticking to the lining of your nose. Ask your pharmacist about nasal barrier balms and nasal sprays.
Time it right
If possible, avoid outside activity when the air is warming up and cooling down as pollen count is highest at these times, around 8-10am and 5-7pm.
Shut the windows
Don’t drive with the windows open, as this will allow pollen to come in. Open bedroom windows at night, but close them when you get up in the morning.
Damp dust regularly
Dusting with a damp or microfibre cloth will collect dust and stop any pollen from becoming airborne.
Wash your hair
“Pollen is sticky and may be in your hair,” says Maureen. “It can then transfer to your pillow and affect you during the night. If you’ve been out in the evening, wash your hair and change your clothes before going into the bedroom.”
Pollen can live in carpet, so make sure you vacuum regularly.
Think about your medication
Talk to your GP or pharmacist about your hay fever, if your symptoms are not controlled by your current treatment.
“Non-sedating antihistamines may be adequate for mild or intermittent hay fever symptoms, but many people will need to use a steriod nasal spray (available from a pharmacy or prescribed by a GP) to treat the inflammation in the nose caused by hay fever,” says Maureen. “This must be used regularly, and relief will be felt after a few days. It should be continued once or twice daily until the hay fever season is over.”
Start treatment early
“Most people wait until symptoms start before they begin treatment, but the nasal spray needs to be started at least two weeks before symptoms appear, so that the medication is already in your system when pollen triggers your hay fever,” says Maureen. “Take your antistamine as soon as your symptoms start.”
Think back to previous years to work out when your hay fever usually starts, so you can try to identify what triggers your symptoms. “For example, grass pollen is in the air from May until August, so you could start taking a steroid nasal spray in April,” says Maureen. “Or earlier if you have symptoms from tree pollens.” Read more about the pollen count, which is a major cause of hay fever symptoms.
You can also talk to your GP or call the Allergy UK helpline for more advice.
Don’t ignore hay fever
Hay fever can make everyday life miserable and tiring, with sneezing, watery eyes, runny nose and an itchy throat. However, many hay fever treatments are available from your GP, and symptoms need to be controlled as hay fever can also cause asthma attacks or increase your risk of developing asthma.
“There is a strong link between hay fever and asthma,” says Maureen. “If you have a food allergy, eczema or hay fever, you’re more likely to develop asthma, so it’s important to take hay fever seriously and treat the symptoms adequately to prevent asthma symptoms.”
There are many hay fever treatments, and symptoms can be controlled.
It’s not possible to completely avoid allergens, but you can reduce your symptoms by taking some steps to limit your exposure to them. It helps to know exactly what you’re allergic to so that you can avoid your specific triggers.
Pollen or molds
- Close doors and windows during pollen season.
- Don’t hang laundry outside — pollen can stick to sheets and towels.
- Use air conditioning in your house and car.
- Use an allergy-grade filter in the ventilation system.
- Avoid outdoor activity in the early morning when pollen counts are highest.
- Stay indoors on dry, windy days.
- Use a dehumidifier to reduce indoor humidity.
- Use a high-efficiency particulate air (HEPA) filter in your bedroom.
- Avoid mowing the lawn or raking leaves, which stirs up pollen and molds.
- Wear a dust mask when doing outdoor activities such as gardening.
- Use allergy-proof covers on mattresses, box springs and pillows.
- Wash sheets and blankets in water heated to at least 130 F (54 C).
- Use a dehumidifier or air conditioner to reduce indoor humidity.
- Vacuum carpets weekly with a vacuum cleaner equipped with a small-particle or HEPA filter.
- Consider removing carpeting, especially where you sleep, if you’re highly sensitive to dust mites.
- Block cracks and crevices where roaches can enter.
- Fix leaky faucets and pipes.
- Wash dishes and empty garbage daily.
- Sweep food crumbs from counters and floors.
- Store food, including pet food, in sealed containers.
- Consider professional pest extermination.
- Remove pets from the house, if possible.
- Bathe your pets on a weekly basis, if possible. Using wipes designed to reduce dander also may help.
- Keep your pets out of the bedroom.
Common complications of hay fever include the following:
- Secondary infection: This is a bacterial infection that occurs in tissues such as the mucous membranes of the nose, throat, or sinuses or the ear that have already been irritated and inflamed by the allergic reaction. Ear infection(otitis) or sinus infection (sinusitis) are common secondary infections of hay fever.
- Rebound nasal congestion (rhinitis medicamentosa): This may result from using decongestant nasal sprays more than twice daily for 3 consecutive days.
- Enlargement of lymph nodes in the nose and throat
- Decreased lung function
- Facial changes: Most of the facial changes are because of local inflammation and congestion. These are temporary and resolve with the treatment of the disease. These include facial swelling, redness around the nose, and allergic “shiners.”
- The crease across the top of the nose caused by frequent nose wiping can persist in children with long-term hay fever.
Problems that may be associated with hay fever include:
- Reduced quality of life. Hay fever can interfere with your enjoyment of activities and cause you to be less productive. For many people, hay fever symptoms lead to absences from work or school.
- Poor sleep. Hay fever symptoms can keep you awake or make it hard to stay asleep.
- Worsening asthma. If you have asthma, hay fever can worsen signs and symptoms, such as coughing and wheezing.
- Sinusitis. Prolonged sinus congestion due to hay fever may increase your susceptibility to sinusitis — an infection or inflammation of the membrane that lines the sinuses.
- Ear infection. In children, hay fever often is a factor in middle ear infection (otitis media).