Allergies arise from an overreaction of the immune system. Normally, the immune system protects the body from invaders such as viruses and bacteria that can cause illness. People with allergies have an immune system that reacts to a harmless substance as though it was harmful.
What the immune system reacts to is called an allergen. Common allergens include:
- Pet dander
- Foods such as eggs and nuts
- Bee stings
A person is exposed to an allergen. The body then develops antibodies to it. When a person is later exposed again to the same allergen, an allergic reaction happens.
There are many treatments for allergy relief. Here are some common classes of medications:
Antihistamines are effective medications used especially with hay fever and other allergies. These medications counter the effects of histamines. Histamines are a substance made by the body to help the immune system fight invaders.
In the case of allergies, these histamines produce unpleasant symptoms such as sneezing, runny nose, and itchy eyes.
Antihistamines are often used to treat hay fever and other allergies.
Antihistamines are available over the counter and by prescription. These medications can be in the form of tablets, liquid, nasal sprays, creams, and eye drops.
Older antihistamines such as Benadryl and Chlor-Trimeton relieve allergy symptoms but can cause drowsiness. People shouldn't drive while using these medications.
Other common side effects of these older antihistamines include:
Newer antihistamines have fewer side effects and are less likely to cause drowsiness, with the exception of Zyrtec. These medications come in tablet form. Some brands include Allegra, Alavert, Clarinex, Claritin, and Zyrtec.
Common side effects of these antihistamines include:
- Dry nose
- Dry mouth
- Ill feeling
Decongestants can be useful in allergy relief by clearing a stuffy nose and sinus congestion. The medications shrink blood vessels in the nose and open up nasal passages.
These medications are often available over the counter and in pill or spray form. Examples of decongestants include Dimetapp, Entex, Propagest, and Sudafed.
Nasal sprays can also rapidly relieve nasal congestion. Many of these medications can be found over the counter such as Flonase and Nasacort.
Pregnant women and people with high blood pressure are advised not to take decongestants and should speak to their doctor.
Side effects of taking decongestants by mouth may include:
- Dry mouth
- Trouble sleeping
Side effects of decongestant nasal sprays include:
- Dry or runny nose
- Temporary burning or stinging in the nose
Nasal corticosteroids relieve symptoms by curbing inflammation that is caused when an allergen is present. These medications require a prescription. Corticosteroid nasal sprays such as Flonase and Nasacort relieve nasal stuffiness, sneezing, and runny nose.
Side effects of nasal corticosteroids include:
- Unpleasant smell in the nose
- Bad taste in the mouth
- Nasal irritation
Epinephrine to stop anaphylaxis
Epinephrine is injected to treat a life-threatening reaction known as anaphylaxis.
Auto-injectable epinephrine is used to treat a life-threatening allergic reaction called anaphylaxis. The prescription medication is used to reverse symptoms such as difficulty breathing, throat swelling, weak pulse, and hives.
Some brands of these medications include EpiPen, Twinject, or Anapen.
Epinephrine is delivered by self-injection. Its effects are rapid but do not last long. As a result, a person should seek medical attention to manage this allergic reaction.
Allergy injections (immunotherapy)
Some people with allergies have benefited from allergy shots or immunotherapy to lessen the allergic reaction. An allergist injects a small amount of the allergen so the body can develop immunity to it. The process can be effective in ending an allergy. It can also stop the progression of a minor allergy into something more serious.
The immunotherapy treatment takes about a year to be effective and is then maintained for another few years. The side effects of treatment are redness and swelling at the injection site. Some people may experience allergy symptoms, such as a stuffy nose.
There are some non-medication alternatives to relieve allergy symptoms. They can be used alone or in combination with medications.
Nasal irrigation washes allergens and mucus out of the nose, which can make breathing easier. Saline is poured or gently pushed into the nostrils using a bulb syringe or neti pot. People should use procedures the U.S. Food and Drug Administration recommend to avoid getting a sinus infection.
Saline nose spray flushes allergens like pollen and dust out of the nose. These sprays are less irritating than nose spray with medications.
Healthy eating has many benefits, including reducing inflammation caused by allergens. Food allergies require avoiding certain foods, but a balanced, nutritious diet can still be achieved. Some anti-inflammatory foods include fish, avocados, broccoli, kale, watermelon, and spices like ginger, oregano, turmeric, and cayenne.
Cold compresses can help with swollen eyes and painful sinuses.
The immune system's overreaction to an allergen leads to inflammation, and that is what causes allergy symptoms. Allergy symptoms vary by the type of allergen and how severe the allergic reaction.
Those who have skin allergy may have symptoms of redness or a rash where they had contact with an allergen such as latex or an ingredient in laundry detergent.
Seasonal allergies or hay fever are very common. Around 10 to 30 percent of people worldwide are affected, and allergies may be increasing.
People with seasonal allergies have symptoms resembling the common cold such as:
Seasonal allergies cause symptoms such as itchy and runny noses and wheezing.
- Itchy nose
- Runny nose
- Swollen eyes
- Itchy throat
People with allergic reactions to foods have different symptoms, some of which can be severe:
- Swelling of lips, mouth, or face
- Stomach cramps
- Hives - a red and itchy rash
- Shortness of breath
Some people with severe allergies to foods, bee stings, or medications may experience anaphylaxis or anaphylactic shock. Some of these symptoms include:
- Stomach cramps
- Narrowing of the airways
- Swollen tongue or throat
- Wheezing and trouble breathing
- Rash or itching
- A weak and rapid pulse
- Nausea, vomiting, or diarrhea
- Dizziness or fainting
When to see a doctor
Allergies can be a minor problem, but can be serious in the case of allergic asthma or anaphylaxis. An allergy specialist can evaluate and prescribe an appropriate treatment.
The American College of Allergy, Asthma and Immunology recommend that people see an allergist in the following cases:
- Difficulty breathing or inability to catch breath
- Hay fever for most of the year
- Over-the-counter medications don't work or have strong side effects
- Allergies interfere with daily life
A doctor specializing in allergies such as an allergist or immunologist can help figure out what is causing symptoms. Allergists commonly conduct skin testing where potential allergens are pricked into the skin. If the spots become swollen, the test confirms an allergen.
Allergens should be avoided, if possible, and there are ways to prevent allergies.
People with food allergies need to be careful about how food has been packaged and prepared. There can be cross-contamination where a small amount of an allergen ends up in a dish. A restaurant serving a peanut sauce might have peanut residue on a kitchen utensil because it wasn't properly cleaned, for example.
Allergens like dust and pollen are hard to avoid altogether. Frequent cleaning of household surfaces and clothing can help. Furry pets can carry allergens in their coats, so regular baths can keep allergies at bay.
Investing in an air purifier with a HEPA filter may offer relief from airborne allergens. Regularly changing air-conditioning filters and keeping windows closed will reduce the amount of pollen from entering the home.