Immunotherapy is meant to train the body's immune system not to react to certain allergens. This treatment might protect broadly against allergens that are hard to avoid such as pollens, dust mites and molds. Biologic medicines make changes to the body's immune system to treat allergic conditions such as asthma, sinusitis, hives and food allergy.

Immunotherapy is carefully timed and monitored while exposure to allergens is slowly increased. Immunotherapy might be useful in several cases, especially when other treatments aren't effective or tolerated.

Shots

Immunotherapy may be given as a series of shots, also called injections, usually one or two times a week. The dose may be increased during this time based on a person's tolerance. The highest tolerated dose can then be given year-round every 2 to 4 weeks.

Side effects might include irritation at the injection site and allergy symptoms such as, sneezing, congestion, hives, and itchy or watery eyes. Rarely, allergy shots can cause anaphylaxis.

Biological medicines given by injection include:

• Dupilumab (Dupixent). This medicine treats asthma, sinus pressure and allergic skin conditions.
• Omalizumab (Xolair). This medicine treats asthma or hives when other medicines don't help.
• Mepolizumab (Nucala). This medicine treats asthma and sinus discomfort.

Pills and liquids

When treating a peanut allergy in children, a pill might help. Although peanuts may still need to be avoided, this medicine might help prevent a severe reaction if peanuts are eaten by accident. It cannot be used as emergency treatment for anaphylaxis.

Side effects include swelling of the throat and anaphylaxis in rare cases. If you have asthma, this treatment may make your symptoms worse.

Oral treatment for peanut allergies:

• Peanut allergy powder (Palforzia).

When treating for dust mites or hay fever, a medicine tablet may be placed under the tongue. This is called sublingual immunotherapy (SLIT). The medicine dissolves and is absorbed under the tongue. This method is known to relieve asthma and allergy symptoms.

SLIT treatment for dust mites:

• House dust mite allergen extract (Odactra).

SLIT treatments for hay fever:

• Short ragweed pollen extract (Ragwitek).
• Sweet vernal, orchard, perennial rye, timothy, and Kentucky blue grass mixed pollens allergen extract (Oralair).
• Timothy grass pollen allergen extract (Grastek).

Epinephrine shots are used to treat a sudden, life-threatening allergic reaction, also called anaphylaxis. Symptoms of anaphylaxis include swelling in the throat and difficulty breathing.

Shots to treat anaphylaxis are given with an autoinjector. This device has a self-injecting syringe and needle. You might need to carry two autoinjectors if there's a chance you have a severe allergy. Severe allergic reactions might be triggered by food, such as peanuts, or insect venom, such as bees and wasps.

A healthcare professional will train you on how to use an epinephrine autoinjector. Get the type that your health professional prescribes, as each brand may work differently. Also, be sure to replace your emergency epinephrine before the expiration date.

Sometimes, a second injection is needed. If anaphylaxis happens, call 911 or get emergency medical care.

Examples of these emergency allergy medicines include:

• Adrenaclick.
• Auvi-Q.
• EpiPen.
• EpiPen Jr.
• Symjepi.

Work with your care team to choose the safest and most effective allergy medicine for you. Even nonprescription medicines have side effects. Some allergy medicines can cause problems when combined with other treatments and conditions.

It's even more important to speak to your care team about allergy medicines if:

• You are pregnant or breastfeeding.
• You have a chronic health condition. These include diabetes, glaucoma, osteoporosis or high blood pressure.
• You take other medicines. Other medicines include herbal supplements.
• You are treating allergies in a child. Children may need different medicines or doses than adults.
• You are treating allergies in an older adult. Some allergy medicines can cause confusion, urinary tract symptoms or other side effects in older adults.
• Your allergy medicine isn't working. Bring the medicine with you in its original bottle or package when you see your healthcare professional.

Keep track of your symptoms. Note when you use your medicines and how much you take. This information can help your care team figure out what works best. You might need to try a few different options to find the most effective medicine with the fewest side effects.

Allergy medications are available as pills, liquids, inhalers, nasal sprays, eyedrops, skin creams and shots (injections). Some are available over-the-counter; others are available by prescription only. Here's a summary of the types of allergy medications and why they're used.

Antihistamines block histamine, a symptom-causing chemical released by your immune system during an allergic reaction.

Pills and liquids

Oral antihistamines are available over-the-counter and by prescription. They ease a runny nose, itchy or watery eyes, hives, swelling, and other signs or symptoms of allergies. Because some of these drugs can make you feel drowsy and tired, take them with caution when you need to drive or do other activities that require alertness.

Antihistamines that tend to cause drowsiness include:

• Diphenhydramine
• Chlorpheniramine

These antihistamines are much less likely to cause drowsiness:

• Cetirizine (Zyrtec, Zyrtec Allergy)
• Desloratadine (Clarinex)
• Fexofenadine (Allegra, Allegra Allergy)
• Levocetirizine (Xyzal, Xyzal Allergy)
• Loratadine (Alavert, Claritin)

Nasal sprays

Antihistamine nasal sprays help relieve sneezing, itchy or runny nose, sinus congestion, and postnasal drip. Side effects of antihistamine nasal sprays might include a bitter taste, drowsiness or feeling tired. Prescription antihistamine nasal sprays include:

• Azelastine (Astelin, Astepro)
• Olopatadine (Patanase)

Eyedrops

Antihistamine eyedrops, available over-the-counter or by prescription, can ease itchy, red, swollen eyes. These drops might have a combination of antihistamines and other medicines.

Side effects might include headache and dry eyes. If antihistamine drops sting or burn, try keeping them in the refrigerator or using refrigerated artificial-tear drops before you use them. Examples include:

• Ketotifen (Alaway, Zaditor)
• Olopatadine (Pataday, Patanol, Pazeo)
• Pheniramine and naphazoline (Visine, Opcon-A, others)

Decongestants are used for quick, temporary relief of nasal and sinus congestion. They can cause trouble sleeping, headache, increased blood pressure and irritability. They're not recommended for people with high blood pressure, cardiovascular disease, glaucoma or hyperthyroidism.

Pills and liquids

Oral decongestants relieve nasal and sinus congestion caused by hay fever (allergic rhinitis). Many decongestants, such as pseudoephedrine (Sudafed), are available over-the-counter.

A number of oral allergy medications contain a decongestant and an antihistamine. Examples include:

• Cetirizine and pseudoephedrine (Zyrtec-D 12 Hour)
• Desloratadine and pseudoephedrine (Clarinex-D)
• Fexofenadine and pseudoephedrine (Allegra-D)
• Loratadine and pseudoephedrine (Claritin-D)

Nasal sprays and drops

Nasal decongestant sprays and drops relieve nasal and sinus congestion if used only for a short time. Repeated use of these drugs for more than three consecutive days may result in a cycle where congestion recurs or gets worse. Examples include:

• Oxymetazoline (Afrin)
• Tetrahydrozoline (Tyzine)

Corticosteroids relieve symptoms by suppressing allergy-related inflammation.

Nasal sprays

Corticosteroid sprays prevent and relieve stuffiness, sneezing and runny nose. Side effects can include an unpleasant taste, nasal irritation and nosebleeds. Examples include:

• Budesonide (Rhinocort)
• Fluticasone furoate (Flonase Sensimist)
• Fluticasone propionate (Flonase Allergy Relief)
• Mometasone (Nasonex)
• Triamcinolone (Nasacort Allergy 24 Hour)

For people who are bothered by the feeling of liquid running down their throats or the unpleasant taste of these sprays, there are two aerosol formulas:

• Beclomethasone (Qnasl)
• Ciclesonide (Zetonna)

Inhalers

Inhaled corticosteroids are often used daily as part of treatment for asthma caused or complicated by reactions to airborne allergy triggers (allergens). Side effects are generally minor and can include mouth and throat irritation and oral yeast infections.

Some inhalers combine corticosteroids with long-acting bronchodilators. Prescription inhalers include:

• Beclomethasone (Qvar Redihaler)
• Budesonide (Pulmicort Flexhaler)
• Ciclesonide (Alvesco)
• Fluticasone (Flovent)
• Mometasone (Asmanex Twisthaler)

Eyedrops

Corticosteroid eyedrops are used to relieve persistent itchy, red or watery eyes when other interventions aren't effective. A physician specializing in eye disorders (ophthalmologist) usually monitors the use of these drops because of the risk of problems, such as cataracts, glaucoma and infection. Examples include:

• Fluorometholone (Flarex, FML)
• Loteprednol (Alrex, Lotemax)
• Prednisolone (Omnipred, Pred Forte, others)

Pills and liquids

Oral corticosteroids are used to treat severe symptoms caused by all types of allergic reactions. Long-term use can cause cataracts, osteoporosis, muscle weakness, stomach ulcers, increased blood sugar (glucose) and delayed growth in children. Oral corticosteroids can also worsen high blood pressure.

Prescription oral corticosteroids include:

• Prednisolone (Prelone)
• Prednisone (Prednisone Intensol, Rayos)
• Methylprednisolone (Medrol)

Skin creams

Corticosteroid creams relieve allergic skin reactions such as itching, redness or scaling. Some low-potency corticosteroid creams are available without a prescription, but talk to your doctor before using these drugs for more than a few weeks.

Side effects can include skin discoloration and irritation. Long-term use, especially of stronger prescription corticosteroids, can cause thinning of the skin and abnormal hormone levels. Examples include:

• Betamethasone (Dermabet, Diprolene, others)
• Desonide (Desonate, DesOwen)
• Hydrocortisone (Locoid, Micort-HC, others)
• Mometasone (Elocon)
• Triamcinolone

Mast cell stabilizers block the release of chemicals in the immune system that contribute to allergic reactions. These drugs are generally safe but usually need to be used for several days to produce the full effect. They're usually used when antihistamines are not working or not well-tolerated.

Nasal spray

Over-the-counter nasal sprays include cromolyn (Nasalcrom).

Eyedrops

Prescription eyedrops include the following:

• Cromolyn (Crolom)
• Lodoxamide (Alomide)
• Nedocromil (Alocril)

A leukotriene inhibitor is a prescription medication that blocks symptom-causing chemicals called leukotrienes. This oral medication relieves allergy signs and symptoms including nasal congestion, runny nose and sneezing. Only one type of this drug, montelukast (Singulair), is approved for treating hay fever.

In some people, leukotriene inhibitors can cause psychological symptoms such as anxiety, depression, strange dreams, trouble sleeping, and suicidal thinking or behavior.

Immunotherapy is carefully timed and gradually increased exposure to allergens, particularly those that are difficult to avoid, such as pollens, dust mites and molds. The goal is to train the body's immune system not to react to these allergens.

Immunotherapy might be used when other treatments aren't effective or tolerated. It is also helpful in reducing asthma symptoms in some patients.

Shots

Immunotherapy may be given as a series of injections, usually one or two times a week. The dose may be increased weekly or every two weeks based on the patient's tolerance. Injections of the maximum tolerated dose may then be given every two to four weeks year round.

Side effects might include irritation at the injection site and allergy symptoms such as sneezing, congestion or hives. Rarely, allergy shots can cause anaphylaxis, a sudden life-threatening reaction that causes swelling in the throat, difficulty breathing, and other signs and symptoms.

Sublingual immunotherapy (SLIT)

With this type of immunotherapy, you place an allergen-based tablet under your tongue (sublingual) and allow it to be absorbed. This treatment has been shown to reduce runny nose, congestion, eye irritation and other symptoms associated with hay fever. It also improves asthma symptoms.

One SLIT tablet contains dust mites (Odactra). Several SLIT tablets contain extracts from pollens of different types of grass, including the following:

• Short ragweed (Ragwitek)
• Sweet vernal, orchard, perennial rye, Timothy and Kentucky blue grass (Oralair)
• Timothy grass (Grastek)

Biological medications

Some medications target a specific reaction in the immune system and try to prevent it from happening. These medications are given as injections. They include dupilumab (Dupixent) to treat allergic skin reactions and omalizumab (Xolair) to treat asthma or hives when other medications don't help.

Side effects of biological medications may include redness, itchiness, or irritation of the eyes and irritation at the injection site.

Epinephrine shots are used to treat anaphylaxis, a sudden, life-threatening reaction. The drug is administered with a self-injecting syringe and needle device (auto-injector). You might need to carry two auto-injectors if there's a chance you could have a severe allergic reaction to a certain food, such as peanuts, or if you're allergic to bee or wasp venom.

A second injection is sometimes needed. As a result, it's important to call 911 or get immediate emergency medical care.

A health care professional will train you on how to use an epinephrine auto-injector. It's important to get the type that your doctor prescribes, as the method for injection may differ slightly for each brand. Also, be sure to replace your emergency epinephrine before the expiration date.

Examples of these medications include:

• Adrenaclick
• Auvi-Q
• EpiPen
• EpiPen Jr

Work with your doctor to choose the most effective allergy medications and avoid problems. Even over-the-counter allergy medications have side effects, and some allergy medications can cause problems when combined with other medications.

It's especially important to talk to your doctor about taking allergy medications in the following circumstances:

• You're pregnant or breast-feeding.
• You have a chronic health condition, such as diabetes, glaucoma, osteoporosis or high blood pressure.
• You're taking other medications, including herbal supplements.
• You're treating allergies in a child. Children need different doses of medication or different medications from adults.
• You're treating allergies in an older adult. Some allergy medications can cause confusion, urinary tract symptoms or other side effects in older adults.
• You're already taking an allergy medication that isn't working. Bring the medication with you in its original bottle or package when you see your doctor.

Keep track of your symptoms, when you use your medications and how much you use. This will help your doctor figure out what works best. You might need to try a few medications to determine which are most effective and have the least bothersome side effects for you.

Allergy medicines are available as pills, liquids, inhalers, nasal sprays, eye drops, skin creams and shots, also called injections. Many allergy medicines are available without a prescription. Here are the different types of medicine options available to treat allergies. Talk with a healthcare professional to find the one that's best for you.