Explain what causes allergies
Allergic reactions generally happen quickly within a few minutes of exposure to an allergen.
They can cause:
- wheezing and coughing
- a runny or blocked nose
- red, itchy, watery eyes
- a red, itchy rash
- worsening of asthma or eczema symptoms
Most allergic reactions are mild, but occasionally a severe reaction called anaphylaxis or anaphylactic shock can happen.
This is a medical emergency and needs urgent treatment.
Is it an allergy, sensitivity or intolerance?
The exaggeration of the normal effects of a substance.
For example, the caffeine in a cup of coffee may cause extreme symptoms, such as palpitations and trembling.
A reaction produced by the body’s immune system when exposed to a normally harmless substance.
Where a substance causes unpleasant symptoms, such as diarrhoea, but does not involve the immune system.
People with an intolerance to certain foods can typically eat a little quantity without having any problems.
Sheet final reviewed: 22 November 2018
Next review due: 22 November 2021
Itchy eyes, a congested nose, sneezing, wheezing and hives: these are symptoms of an allergic reaction caused when plants release pollen into the air, generally in the spring or drop.
Numerous people use hay fever as a colloquial term for these seasonal allergies and the inflammation of the nose and airways.
But hay fever is a misnomer, said Dr. Jordan Josephson, an ear, nose and throat doctor and sinus specialist at Lenox Hill Hospital in New York City.
«It is not an allergy to hay,» Josephson, author of the book «Sinus Relief Now» (Perigee Trade, 2006), told Live Science. «Rather, it is an allergy to weeds that pollinate.»
Doctors and researchers prefer the phrase allergic rhinitis to describe the condition. More than 50 million people experience some type of allergy each year, according to the Asthma and Allergy Foundation of America.
In 2017, 8.1% of adults and 7.7% of children reported own allergic rhinitis symptoms, according to the Centers for Disease Control and Prevention (CDC). Worldwide, between 10 and 30% of people are affected by allergic rhinitis, Josephson said.
In 2019, spring arrived early in some parts of the country and later in others, according to the National Phenology Network (NPN). Spring brings blooming plants and, for some, lots of sneezing, itchy, watery eyes and runny noses.
According to NPN data, spring reared its head about two weeks early in areas of California, Nevada and numerous of the Southern and Southeastern states.
Much of California, for example, is preparing for a brutal allergy season due to the large quantity of winter rain. On the other hand, spring ranged from about one to two weeks tardy in the Northwest, the Midwest and the Mid-Atlantic U.S. [Watch a Massive ‘Pollen Cloud’ Explode from Late-Blooming Tree]
What causes allergies?
Allergies occur when the body’s immune system reacts to a specific substance as though it’s harmful.
It’s not clear why this happens, but most people affected own a family history of allergies or own closely related conditions, such as asthma or eczema.
The number of people with allergies is increasing every year.
The reasons for this are not understood, but 1 of the main theories is it’s the result of living in a cleaner, germ-free environment, which reduces the number of germs our immune system has to deal with.
It’s thought this may cause it to overreact when it comes into contact with harmless substances.
How to manage an allergy
In many cases, the most effective way of managing an allergy is to avoid the allergen that causes the reaction whenever possible.
For example, if you own a food allergy, you should check a food’s ingredients list for allergens before eating it.
There are also several medicines available to help control symptoms of allergic reactions, including:
- decongestants – tablets, capsules, nasal sprays or liquids that can be used as a short-term treatment for a blocked nose
- antihistamines – these can be taken when you notice the symptoms of a reaction, or before being exposed to an allergen, to stop a reaction occurring
- lotions and creams, such as moisturising creams (emollients) – these can reduce skin redness and itchiness
- steroid medicines – sprays, drops, creams, inhalers and tablets that can assist reduce redness and swelling caused by an allergic reaction
For some people with extremely severe allergies, a treatment called immunotherapy may be recommended.
This involves being exposed to the allergen in a controlled way over a number of years so your body gets used to it and does not react to it so severely.
The symptoms of allergic rhinitis may at first feel love those of a freezing. But unlike a freezing that may incubate before causing discomfort, symptoms of allergies generally appear almost as soon as a person encounters an allergen, such as pollen or mold.
Symptoms include itchy eyes, ears, nose or throat, sneezing, irritability, nasal congestion and hoarseness. People may also experience cough, postnasal drip, sinus pressure or headaches, decreased sense of smell, snoring, sleep apnea, fatigue and asthma, Josephson said.
[Oral Allergy Syndrome: 6 Ways to Avoid an Itchy, Tingling Mouth]
Many of these symptoms are the immune system’s overreaction as it attempts to protect the vital and sensitive respiratory system from exterior invaders. The antibodies produced by the body hold the foreign invaders out, but also cause the symptoms characteristic of allergic responses.
People can develop hay fever at any age, but most people are diagnosed with the disorder in childhood or early adulthood, according to the Mayo Clinic. Symptoms typically become less severe as people age.
Often, children may first experience food allergies and eczema, or itchy skin, before developing hay fever, Josephson said.
«This then worsens over the years, and patients then develop allergies to indoor allergens love dust and animals, or seasonal rhinitis, love ragweed, grass pollen, molds and tree pollen.»
Hay fever can also lead to other medical conditions. People who are allergic to weeds are more likely to get other allergies and develop asthma as they age, Josephson said.
But those who get immunotherapy, such as allergy shots that assist people’s bodies get used to allergens, are less likely to develop asthma, he said.
Getting assist for allergies
See a GP if you ponder you or your kid might own had an allergic reaction to something.
The symptoms of an allergic reaction can also be caused by other conditions.
A GP can assist determine whether it’s likely you own an allergy.
If they ponder you might own a mild allergy, they can offer advice and treatment to assist manage the condition.
If your allergy is particularly severe or it’s not clear what you’re allergic to, they may refer you to an allergy specialist for testing and advice about treatment.
Find out more about allergy testing
Substances that cause allergic reactions are called allergens.
The more common allergens include:
- insect bites and stings
- animal dander, tiny flakes of skin or hair
- medicines – including ibuprofen, aspirin and certain antibiotics
- food – particularly nuts, fruit, shellfish, eggs and cows’ milk
- latex – used to make some gloves and condoms
- dust mites
- mould – these can release little particles into the air that you can breathe in
- grass and tree pollen – an allergy to these is known as hay fever (allergic rhinitis)
- household chemicals – including those in detergents and hair dyes
Most of these allergens are generally harmless to people who are not allergic to them.