Key takeaways:
People rarely develop a tolerance to allergy medications. Common medications like Zyrtec, Allegra, Flonase, and Claritin usually don’t stop working over time.
If you have seasonal allergies and notice that your allergy medicine stops working, you may have developed new allergies.
It’s time to check for new allergies if your nose is still stuffy and you keep sneezing after taking your regular allergy medicine. You may need a new treatment plan, not just more medication.
Have you noticed that your allergy medicines don’t work as well as they used to? You’re not alone. In a national survey, people with allergies reported changing their allergy medications because they’re not effective enough.
So why do allergy medications stop working? Can you really build up a tolerance for them?
If your allergy medication isn’t working, you probably want to improve your symptoms fast. The best solution depends on what’s causing your allergies and why your medication isn’t working.
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Here are seven reasons your allergy medication may not be working, and what you can do about it.
1. Changes in your immediate environment
Changes in your environment can make allergies worse. Things like worsening air pollution, warmer temperatures, and fumes from chlorinated swimming pools trigger allergy symptoms. Some of these triggers also overlap with allergy season, which can give you a double hit. This can make it seem like your allergy medication isn’t working, when your symptoms may just be stronger than before.
Check and see if there are changes in your immediate environment. Some things to consider:
Did you recently move to a new area? You may be exposed to new levels of air pollution or different pollens and grasses.
Did you recently get a new pet? Pet dander can worsen your allergies. Being around a partner’s pet or other animals can also trigger your allergies.
Have you been remodeling? Construction and redecorating can stir up dust that has been settled for a long time. Dust can also cling to furniture or items brought in from your basement, attic, or storage unit. This dust can aggravate your allergies.
Did you garden or change your landscaping? New trees, plants, and flowers can aggravate your allergies. Plants added in the fall can release pollen that can worsen your allergies in the spring and summer.
If environmental changes are making your allergies worse, you may need to adjust your medication dose or add another medication. You may also need a plan to avoid new allergens. Allergy-tracking tools can help you plan your day and avoid times when pollen levels are high.
2. New allergies
You can develop new allergies as you get older, even if you’re exposed to the same allergens year after year.
Medications that worked for your previous allergies may not work as well for new allergies. If your allergy medication isn’t working or you have new allergy symptoms, it may be time to visit your healthcare professional for an updated round of allergy tests. If you have new allergies, you may need to change your medications. You may also need a plan to avoid new triggers.
3. Not taking your medications on schedule
People often take allergy medications only when their symptoms start to act up. But this may not be the best approach. If you have year-round (perennial) allergies, sticking with scheduled medication may work better.
If you have seasonal allergies, you may also need to stick with a schedule through allergy season. And you should start your allergy medication a few weeks before allergy season starts. This gives your immune system time to prepare before allergens come out.
If keeping up with daily allergy medications isn’t working for you, talk to your healthcare professional about other options, like allergy shots. Allergy shots are time intensive, but they can be a great alternative to taking allergy medications every day.
4. Rebound congestion
Some medications that relieve allergy symptoms, like a stuffy nose and sneezing, aren’t meant to be used long term. Medications that have oxymetazoline and phenylephrine are only meant to be used for a short time. Using them for too long can lead to rebound congestion.
Rebound congestion develops when your body gets used to these medications. When you stop using them, you may develop a severe stuffy nose that can take months to go away.
Oxymetazoline and phenylephrine are available over the counter (OTC) and are found in many decongestants. But they’re not meant for daily allergy treatment. If you’ve been relying on these medications, you’ll need to switch to other options, like nasal steroid sprays or antihistamine pills.
5. Your medications are expired
If your allergy medication doesn’t seem to be working, check the expiration date. Taking an expired allergy medication isn’t likely to harm you. But it may not work well. The FDA advises against using expired medications. That’s because there’s no guarantee that medicines are safe and effective past their expiration date. Replacing expired medications may be enough to bring you relief.
Keep in mind that epinephrine auto-injectors (EpiPens) shouldn’t be kept after their expiration date. EpiPens are used to treat life-threatening allergic reactions.
6. High stress levels
Stress can increase your sensitivity to allergens and kick your allergic response into high gear. Think about whether your stress levels have been higher than usual. If they have been, try to lower your stress levels using tools like meditation, therapy, or exercise.
If you’ve stuck to your allergy-medication schedule, reduced your exposure to allergens, and tried to reduce your stress levels, and you’re still suffering from allergy symptoms, it might be time to see an allergy specialist. They can check for new allergen sensitivities and give you advice on what steps to take next.
7. Not combining therapy
Many people can control their allergy symptoms with just one medication, like an oral antihistamine. But some people need more than one medication. For example, using an antihistamine nasal spray along with a steroid nasal spray may work better to control nasal allergy symptoms. Some studies suggest using both sprays together can relieve allergy symptoms better than using either one alone.
Talk with your healthcare team about combination therapy to help your allergy symptoms. Choosing an allergy plan isn’t always straightforward. Studies suggest that adding an oral antihistamine may not help much if a nasal steroid spray isn’t working on its own. Your healthcare team can help you find the right options.
Do people build up resistance to allergy medicines?
Developing a resistance to allergy medications isn’t common.
Inhaled steroids, like fluticasone (Flonase) and triamcinolone (Nasacort), are first-choice treatments for chronic seasonal allergies. Both are available without a prescription and don’t lead to resistance.
Antihistamines are another popular choice for treating allergies, such as:
Loratadine (Claritin)
Fexofenadine (Allegra)
Cetirizine (Zyrtec)
Studies show that people don’t build up resistance to these medications.
Can you be allergic to allergy medication?
Allergies to allergy medications are very rare. There have been cases where antihistamines like cetirizine and hydroxyzine caused rashes and hives.
Contact your healthcare team right away if you think your allergy medication is making your symptoms worse. Get emergency medical treatment if you have symptoms of a serious allergic reaction, like throat swelling or difficulty breathing.
Frequently asked questions
Some allergy medications work quickly, while others take weeks to show maximum effect. For example, oral antihistamines start working within hours. Some nasal decongestant sprays can bring relief within minutes. Steroid nasal sprays usually take weeks to show effect.
There are several reasons why allergies may not go away with medication. You may not be using the right medication for your symptoms or taking the best dose. Some medications, like steroid nasal sprays, just need more time to work. You may also have developed new allergies that need different treatment. If your allergies aren’t getting better, talk with your healthcare team to find a better care plan.
It’s very rare to develop hives or other symptoms of an allergic reaction after taking oral antihistamines. But some people can react to additives, dyes, or preservatives in allergy medication. Seek immediate medical care if you develop hives, lip or tongue swelling, trouble breathing, or other signs of anaphylaxis after taking antihistamines.
Experts advise against using expired medications. Expired medicines may not be safe to take. They may not work well either.
Some allergy medications work quickly, while others take weeks to show maximum effect. For example, oral antihistamines start working within hours. Some nasal decongestant sprays can bring relief within minutes. Steroid nasal sprays usually take weeks to show effect.
There are several reasons why allergies may not go away with medication. You may not be using the right medication for your symptoms or taking the best dose. Some medications, like steroid nasal sprays, just need more time to work. You may also have developed new allergies that need different treatment. If your allergies aren’t getting better, talk with your healthcare team to find a better care plan.
It’s very rare to develop hives or other symptoms of an allergic reaction after taking oral antihistamines. But some people can react to additives, dyes, or preservatives in allergy medication. Seek immediate medical care if you develop hives, lip or tongue swelling, trouble breathing, or other signs of anaphylaxis after taking antihistamines.
Experts advise against using expired medications. Expired medicines may not be safe to take. They may not work well either.
The bottom line
It’s rare for people to develop tolerance to allergy medication. But some people still have a stuffy nose or sneezing after taking it. This doesn’t always mean the allergy medication isn’t working. Allergies can change over time or worsen because of environmental changes, aging, or stress.
Talk with your healthcare team if you feel like your allergy medication isn’t working. They may recommend allergy testing or changing your treatment plan.
Why trust our experts?
References
Asthma and Allergy Foundation of America. (2006). New survey suggests patients want fast, long relief of allergy symptoms.
Bucklin, S. (2017). Adult-onset allergies are, unfortunately, a real thing. The Cut.
Dave, N. D., et al. (2012). Stress and allergic diseases. Immunology and Allergy Clinics of North America.
Dykewicz, M. S., et al. (2020). Rhinitis 2020: A practice parameter update. The Journal of Allergy and Clinical Immunology.
Seidman, M. D., et al. (2015). Clinical practice guideline allergic rhinitis. Clinical Otolaryngology-Head and Neck Surgery.
U.S. Food and Drug Administration. (2024). Don’t be tempted to use expired medicines.
Valovirta, E., et al. (2008). Patient adherence to allergic rhinitis treatment: Results from patient surveys. The Medscape Journal of Medicine.
