Allergies are a common condition that occur when the immune system overreacts to harmless substances, such as pollen, mold, or pet dander, that are normally present in the environment. Allergic reactions can range from mild symptoms, such as itching and runny nose, to more severe symptoms, such as difficulty breathing and anaphylaxis.
Symptoms of allergies
Allergic reactions produce many different symptoms and affect people in different ways. Some of the most common symptoms include the following:
- sinus pain (feelings of pressure or pain high up in the nose, around the eyes and at the front of the skull),
- runny nose,
- nettle rash/hives,
- itchy eyes, ears, lips throat and palate (roof of mouth),
- shortness of breath, and
- sickness, vomiting and diarrhoea.
- Swelling of the face, lips, or tongue
- Abdominal cramps, nausea, or diarrhea
It is important to remember that these symptoms can also be caused by conditions other than allergies, and some may be illnesses themselves. See your GP or ask your pharmacist for advice if you are not sure what is wrong.
Allergies are not the same as an intolerance
There is a difference between an allergy and an intolerance to certain substances, such as a lactose intolerance (lactose is a sugar found in milk). An allergic reaction always involves your immune system and can be tested by measuring specific immune responses. An intolerance does not involve your immune system, so allergy tests will not highlight the problem.
People with an intolerance to certain foods can typically eat a small amount without having any problems. In contrast, people with a food allergy will have a bad reaction if they come into contact with even the tiniest amount of the food that they are allergic to.
Seasonal allergies, also known as hay fever or seasonal allergic rhinitis, are a type of allergy that occur during certain times of the year. Seasonal allergies are typically caused by pollen from trees, grasses, or weeds. The symptoms of seasonal allergies can include sneezing, runny or stuffy nose, itching or watering eyes, and coughing.
Allergies on the Skin:
Allergies can also affect the skin, causing a range of symptoms, including itching, redness, and hives. Skin allergies are often caused by exposure to irritants, such as soap, detergents, or cosmetics, or to insect bites or stings. In some cases, skin allergies can also be caused by food or medication.
Causes of allergies
Allergies are caused by the body’s immune system reacting to allergens as if they were harmful. The immune system does this by making antibodies to fight off the allergen. Antibodies are special proteins made in the immune system to fight off viruses and infections that could harm us.
When the body comes into contact with an allergen, the antibody released is called immunoglobulin E (IgE). This antibody causes other blood cells to release more chemicals, including histamine (a protein that is involved in many allergic reactions), which together cause the symptoms of an allergic reaction. Histamine causes most of the typical symptoms that happen in an allergic reaction. For example it:
- makes your muscles contract, including those in the walls of the air tubes of your lungs,
- increases the amount of fluid that is released from small veins, causing membranes to swell.
- increases the amount of mucus produced in your nose lining, and causes local itching and burning.
Some people are predisposed to allergy. This means that they are more likely to develop an allergy because it runs in their family. If you are predisposed to an allergy, the condition is called atopy. People who are atopic are more likely to develop allergies because their body produces more IgE antibody than normal.
Although atopy is inherited, environmental factors also play a part in the development of allergic disorders.
The exact role that the environment plays is unknown, but studies have shown that a number of factors seem to increase the chance of a child developing atopy. These include:
- growing up in a house with smokers,
- exposure to dust mites,
- exposure to pets, and
- using antibiotics.
Boys are more likely to develop atopy than girls, as are babies who have a low birth weight. The reasons for this are unclear.
There are thousands of allergens. Some of the most common include:
- house dust mites,
- grass and tree pollens,
- pet hair or skin flakes,
- fungal or mould spores,
- food (milk, egg, wheat, soya, seafood, fruit and nuts),
- wasp and bee stings,
- certain medication, such as penicillin, aspirin or types of opiates like codeine,
- latex, and
- nickel, rubber, preservatives and chemical resins.
Diagnosing allergies typically involves a combination of medical history, physical examination, and allergy tests. The goal of allergy testing is to determine what specific substances are triggering your allergy symptoms.
There are several types of allergy tests, including:
- Skin Tests: Skin tests are the most common type of allergy test. They involve exposing a small amount of the suspected allergen to the skin, usually on the arm or back, and then pricking the skin. If a red, raised bump appears, it indicates that an allergy to the substance is present.
- Blood Tests: Blood tests can measure the levels of specific antibodies in the blood and can help diagnose allergies to substances that are not tested in skin tests, such as food or medication allergies.
- Provocative Testing: Provocative testing involves exposing the individual to a small amount of the suspected allergen in a controlled environment to see if an allergic reaction occurs.
- Challenge Tests: Challenge tests are similar to provocative testing but are usually done in a medical setting to monitor the reaction more closely.
- Patch Tests: Patch tests are used to diagnose skin allergies, such as contact dermatitis. A small amount of the suspected allergen is placed on a patch, which is then applied to the skin.
It is important to work closely with an allergist to determine the best course of action for your allergy diagnosis. The allergist may recommend a combination of tests, depending on your individual symptoms and medical history.
Once the allergy has been diagnosed, the allergist can help develop a treatment plan, which may include medications, allergen immunotherapy, lifestyle changes, or other treatments. The goal of treatment is to relieve symptoms, prevent serious reactions, and improve quality of life.
Treatments for allergies
Wherever possible, the most effective way of treating allergies is to avoid all contact with the allergen causing the reaction.
There are many drugs available to treat the common symptoms of allergies, such as runny nose, itchy mouth and sneezing. Many of these treatments are available over the counter. Ask your pharmacist or healthcare provider for advice.
- Antihistamines: Antihistamines treat allergies by blocking the action of the chemical histamine, which the body releases when it thinks it is under attack from an allergen. Antihistamines can be taken in tablet, cream and liquid form. They can also be taken in the form of eye drops and nasal drops.
- Decongestants: Decongestants help to relieve symptoms such as a blocked nose, which is often caused by hayfever and dust and pet allergies. Decongestants can be taken as tablets, capsules, nasal sprays or in liquid form.
- Nasal sprays and eye drops: Nasal sprays can be used to reduce swelling and irritation in your nose, and eye drops will help to relieve sore, itchy eyes. However, some sprays and drops are only suitable for adults. Ask your GP or pharmacist for advice before buying treatments for children.
- Leukotriene receptor antagonists: Leukotriene receptor antagonists work by blocking the effects of leukotrienes – chemicals released during an allergic reaction that cause inflammation of your airways. They are normally used in the treatment of asthma when other treatments have proved ineffective.
- Other medicines: Medicines such as sodium cromoglicate and corticosteroids can be used regularly to stop symptoms developing. These are commonly available as nasal sprays and eye drops.
- Hyposensitisation (immunotherapy): Another form of treatment for allergies is hyposensitisation, which is also sometimes known as immunotherapy. It can be used to help people who have a specific allergy to something like bee stings. You will gradually be introduced to more and more of the allergen to encourage your body to make antibodies that will stop future reactions.
- This type of treatment must only be carried out under the close supervision of a doctor because there is a risk that it may cause a serious allergic reaction called anaphylactic shock (see ‘complications’ section). Hyposensitisation is normally only recommended for the treatment of hayfever that has not responded to other treatment, and for allergies to bee and wasp stings.
- Treating anaphylaxis: Less than one in 1000 people with an allergy experience a severe allergic reaction (anaphylaxis). These are treated with an adrenalin injection, called an epi-pen or anapen, which you usually administer yourself. Use the adrenaline injection as soon as you experience respiratory symptoms, such as difficulty breathing, and call for emergency medical help. If your symptoms are not relieved within five to 10 minutes, you’ll need another injection to help get your symptoms under control.
Your doctor or an allergy consultant can prescribe adrenaline injections. If you have severe allergic reactions, carry two with you at all times.
Complications of allergies
Allergies can cause a range of symptoms, from mild to severe. In some cases, untreated or poorly managed allergies can lead to serious complications, including:
- Anaphylaxis: Anaphylaxis is a severe, life-threatening reaction to an allergen. Symptoms include difficulty breathing, hives, swelling, low blood pressure, and loss of consciousness. Anaphylaxis requires immediate medical attention.
- Asthma: Allergies can trigger asthma symptoms, including wheezing, coughing, and difficulty breathing. In severe cases, asthma attacks can be life-threatening.
- Sinusitis: Allergic rhinitis, also known as hay fever, can lead to inflammation and swelling in the sinuses, causing sinusitis. Sinusitis can cause headaches, facial pain, and pressure, as well as nasal congestion and discharge.
- Ear infections: Allergic rhinitis can also lead to ear infections, particularly in children. The inflammation and swelling in the nasal passages can block the Eustachian tubes, leading to fluid buildup in the middle ear.
- Eczema: Eczema is a skin condition that can be triggered by allergies. It causes dry, itchy, and inflamed skin, which can lead to open sores and infections.
- Chronic fatigue: Allergies can cause fatigue and sleep disturbances, which can lead to chronic fatigue. This can have a significant impact on daily life and productivity.
- Mental health: Allergies can also have a negative impact on mental health, causing anxiety, stress, and depression.
It is important to seek medical attention for allergy symptoms and to work with an allergist to develop a comprehensive treatment plan to prevent serious complications. This may include medications, allergen immunotherapy, lifestyle changes and other treatments.
Can allergies cause fever?
Yes, in some cases, allergies can cause a low-grade fever. A fever is a sign that the body is fighting an infection or inflammation. Allergic reactions can cause inflammation in the body, which can result in a fever.
However, it is important to note that a fever is not a common symptom of allergies and is more commonly associated with infections. If you are experiencing a fever along with other symptoms, it is important to seek medical attention to determine the cause and receive appropriate treatment.
In addition, some medications used to treat allergies, such as corticosteroids, can also cause a fever. If you are taking allergy medication and develop a fever, it is important to contact your healthcare provider or doctor for further evaluation and guidance.
Can allergies cause sore throat?
Yes, allergies can cause a sore throat. Allergic rhinitis, also known as hay fever, can cause inflammation and swelling in the throat, leading to a sore throat. In addition, postnasal drip, which occurs when excess mucus drains from the sinuses into the throat, can also cause a sore throat.
Other symptoms of allergic rhinitis that can contribute to a sore throat include nasal congestion, sneezing, and coughing. Allergic reactions to food or medications can also cause a sore throat.
If you are experiencing a sore throat along with other allergy symptoms, it is important to seek medical attention to determine the cause and receive appropriate treatment. In some cases, antibiotics may be necessary to treat an infection that is causing a sore throat, while antihistamines and decongestants can be used to relieve allergy symptoms.
It is important to work with your healthcare provider or doctor to determine the best course of action for your individual needs and to receive appropriate treatment for your symptoms.