How to determine which allergy medicine works best for you

• The three main types of allergy medicine are antihistamines, corticosteroid nasal sprays, and decongestants.
• Sometimes, a combination of these medications will work to treat your seasonal allergies — though each have varying side effects and should be used in different situations.
• If these types of allergy medicine don't reduce allergy symptoms, you may want to consider immunotherapy, or allergy shots.
• This article was medically reviewed by Omid Mehdizadeh, MD, otolaryngologist and laryngologist at the Pacific Neuroscience Institute's Pacific Eye, Ear & Skull Base Center at Providence Saint John's Health Center in Santa Monica, CA.
• Visit Insider's Health Reference library for more advice.

Hay fever, also known as allergic rhinitis or seasonal allergies, affects up to 30% of people worldwide. It's caused by an allergic reaction to substances like pollen, mold, or dust, which can lead to symptoms such as nasal congestion, sneezing, runny nose, and irritated eyes.

There are many ways to treat seasonal allergies. For example, if pollen triggers your allergies, then you can stay indoors when pollen counts are high, and make sure to wash your clothes and body after being exposed to pollen outside.

Additionally, air purifiers may be helpful for clearing allergens from your home. Nasal salt water rinses, such as a neti pot, can also flush your sinuses and remove allergy-causing particles.

But if you can't manage your allergies with these natural remedies, and the symptoms are still severe, you may want to try medication. Here's how each kind of allergy medicine works.

Types of allergy medicine

There are three main types of allergy medicine:

• Antihistamines are the first line of defense for relieving a runny nose, sneezing, post-nasal drip, itchy eyes, and itchy skin.
• Nasal sprays can help reduce congestion and sneezing.
• Decongestants can help relieve a stuffy nose and sinus congestion.

While these medications will not cure your allergies, they can help manage symptoms and improve your quality of life, says Atul N. Shah, MD, an allergist and founder of the Center for Asthma & Allergy.

You may even find a combination of these medications helpful, as they each treat individual aspects of your allergy symptoms and can be taken for different reasons.

However, because over the counter (OTC) medications may contain multiple ingredients, you should ask your doctor or pharmacist about which are safe to combine before you do so.

Antihistamines

Antihistamines block your immune system from creating histamines, which are chemicals your body releases during an allergic reaction that cause allergy symptoms.

While histamines are a helpful part of your immune response, taking an antihistamine can help manage nasal congestion, runny nose, sneezing, irritated eyes, or itchy skin.

Some common antihistamines that are available without a prescription, and are considered non-drowsy, include:

• Allegra (fexofenadine)
• Claritin (loratadine)
• Zyrtec (cetirizine)

Over-the-counter antihistamines that contain diphenhydramine — like Benadryl — or chlorpheniramine — like Chlor-Trimeton — may cause drowsiness, so you shouldn't take them before driving or doing other activities that require you to be alert.

Drowsy allergy medicine is best taken before bed, to get better sleep if you're exposed to allergies. You should talk to your doctor before taking medication that causes drowsiness, as it can worsen symptoms of some conditions like dementia.

For more severe allergy symptoms, or if you're experiencing side effects from OTC products, your doctor may prescribe an antihistamine with a stronger dosage and fewer side effects.

Some antihistamines that are available with a prescription include Atarax (hydroxyzine), Clarinex (desloratadine), and Xyzal (levocetirizine).

Along with drowsiness, the side effects of antihistamines may include:

• Constipation
• Dry mouth
• Nervousness
• Lack of appetite

If you're experiencing these side effects, you should ask your doctor about changing the dosage or using a different product.

However, you shouldn't take antihistamines if you have any of the following conditions:

• Enlarged prostate
• Epilepsy
• Glaucoma
• Overactive thyroid

Ask your health care provider about what antihistamines are safe for your child. If you are pregnant or breastfeeding, consult with your doctor before taking an antihistamine.

A Centers for Disease Control (CDC) review on the association between antihistamines and birth defects found that most antihistamines — including Benadryl, Claritin, and Zyrtec — are safe to take during your pregnancy.

Nasal sprays

The corticosteroids in nasal sprays relieve congestion by reducing the swelling in your nasal passages. This medicine can help prevent the onset of symptoms, and Shah says it should be taken two to four weeks before pollen season to be fully effective.

"Start using a corticosteroid nose spray before the season starts, and add it if antihistamines do not control all the allergy symptoms," Shah says. "Using the corticosteroid nose sprays regularly can reduce the need for decongestants."

The following corticosteroid nasal sprays are available over the counter:

• ClariSpray (fluticasone)
• Flonase (fluticasone)
• Nasacort (triamcinolone)

Some corticosteroid nasal sprays, such as Nasonex (mometasone) and Zetonna (ciclesonide), are available only with a prescription.

Some of the possible side effects of using a corticosteroid nasal spray are:

• Nasal dryness, burning, or itching
• Nosebleeds

If you're experiencing these side effects, you should stop using the nasal spray and ask your doctor about changing the dosage or using a different product.

You shouldn't use a corticosteroid nasal spray if you have any of the following conditions:

• An infection in your nose
• Recent surgery on your nose
• Pulmonary tuberculosis (PB)
• Acute angle glaucoma

If you are pregnant or breastfeeding, consult with your doctor before using a nasal spray. Ask your health care provider about corticosteroid nasal sprays that are safe for your child.

Decongestants

Decongestants shrink the blood vessels and tissue inside your nose, allowing more air to pass through and making it easier to breathe.

Shah says that decongestants are better to use in combination with antihistamines, because taken together, the medications are more effective at reducing nasal congestion and other seasonal allergy symptoms.

The following are some of the decongestants available over the counter:

• Afrin nasal spray
• Sudafed (pseudoephedrine)
• Sudafed PE (phenylephrine)
• Zyrtec-D (cetirizine with pseudoephedrine)

Some of the side effects of decongestants may include:

• Increased blood pressure or heart rate
• Nervousness
• Sleeplessness

If you're experiencing an unpleasant reaction to the decongestant you're using, you should ask your doctor or pharmacist to recommend a different product.

The American Academy of Allergy, Asthma, and Immunology (AAAAI) warns that you should avoid using a decongestant nasal spray for more than four consecutive days since it may worsen your stuffy nose and lead you to become dependent on the spray.

You shouldn't take a decongestant if you have any of these conditions:

• Enlarged prostate
• Heart disease
• High blood pressure

If you have any heart conditions, check with your doctor before using a decongestant.

You shouldn't give a decongestant to children younger than 6 years old, according to the American Academy of Family Physicians. If you are pregnant or breastfeeding, consult with your doctor before taking a decongestant.

The bottom line

If your allergies are severe, talk with your doctor about trying these medications before allergy season. Together, you'll be able to determine which allergy medicine works best for you.

If you'd like to purchase one of these allergy medications, or another remedy such as an air purifier, Insider Reviews has complied a list of the best allergy medicine remedies.

And, if these main types of allergy medicine don't help reduce symptoms, there may be other options you can ask your doctor about. Leukotriene inhibitors, such as Singular, target pathways in the body that cause allergies, and this type of medication may work better for you.

Lastly, immunotherapy — or allergy shots — can also regulate your allergies in the long term and help prevent flare-ups in your symptoms each allergy season.

Related articles from our Health Reference library:

• When is allergy season? Symptoms and treatment for seasonal allergies
• All the ways you can control your allergies, from air filters to saltwater rinses
• Is it a cold or allergies? How to categorize your symptoms and treat them appropriately
• Hay fever is an allergic reaction that causes sneezing and a runny nose
• How to get rid of a runny nose from both allergies and illness