Can Allergies Cause Fatigue?

By Andrew Yocum, MD
Medically reviewed checkmarkMedically reviewed
April 1, 2022

If you suffer from allergies, you already know how frustrating it can be to deal with a runny nose, itchy eyes, and sneezing.

But there’s another common symptom you may not associate with your allergies: fatigue. 

Allergies can make you tired for several reasons, including from the allergic reaction itself. Other indirect factors, such as difficulty sleeping, might also make you fatigued during the day.

Either way, it’s important to identify the cause of your allergies so you can avoid triggers.

A doctor can help you identify what’s causing your symptoms, along with recommending a treatment to help alleviate them.

In this article, I’ll explain whether allergies can cause fatigue.

I’ll also explore how to manage fatigue associated with allergies, and finally, when to see a doctor for allergies. 

Do Allergies Cause Fatigue?

Allergy symptoms occur when your body’s immune system reacts to a substance you’re allergic to.

As part of the antibody response, your body releases substances called immunoglobulin E and histamine.

These substances create inflammation in your body to fend off the allergens, which may cause you to experience allergy symptoms such as: 

In addition to these classic allergy symptoms, studies suggest this whole-body inflammation caused by an allergic reaction can also make you feel tired. 

You may also notice you feel mentally foggy when you have allergies.

That’s because when you experience nasal congestion, you may breathe in less oxygen through your nose.

This can interfere with your ability to concentrate on tasks or remember things, which some people call “brain fog.”

Allergy symptoms can also cause difficulty sleeping. If you’re tossing and turning at night due to a stuffy nose or sneezing, you might feel fatigued the next day. 

Lastly, it’s possible your allergy medication could be making you tired.

For example, diphenhydramine (Benadryl) is known to make people sleepy, so it’s often used as a sleep aid.

Talk to your doctor about the best allergy medication for you if you suspect yours is making you feel tired. 

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How To Manage Fatigue Associated With Allergies

Managing fatigue from allergies usually requires figuring out how to best manage the allergy itself.

If you’re struggling with allergies and associated fatigue, your doctor—or an allergist—can diagnose your allergy and recommend a treatment plan to stave off tiredness and other allergy symptoms. 

Here are some of the most impactful ways to improve fatigue from allergies:

Figure out what’s causing allergies

Allergy symptoms are a sign your body is fighting off an allergen.

So to best manage those symptoms, it’s important to identify what you’re allergic to. 

If you have allergy symptoms that only happen certain times of the year (seasonal allergies) you might have allergic rhinitis (a.k.a. hay fever).

The most common causes of allergic rhinitis include: 

  • Pollen, which usually causes allergies in the spring and early summer
  • Mold, or tiny fungi that float in the air like pollen, which usually causes symptoms in late summer and early fall

Other forms of allergic rhinitis also stem from environmental allergens, but they may occur year-round:

  • Animal dander
  • Dust mites, tiny organisms found in household fibers

Other common allergy causes may be easier to identify, because they’re not circulating in the environment: 

  • Insects and insect stings 
  • Latex
  • Foods
  • Medications

If you have persistent allergy symptoms and you’re not sure what you’re allergic to, speak with your doctor.

An allergist can diagnose you via allergy testing and recommend a treatment to help. 

Avoid allergy triggers

Once you’re aware of your allergy triggers, do your best to avoid them.

For example, if you commonly sneeze and itch around animals, avoid visiting homes with pets.

If that’s not possible, then taking an over-the-counter allergy medication before encountering your allergy trigger might help. 

Certain triggers aren’t easy to avoid; for example, if you have seasonal rhinitis, you’ll probably still have to go outside in the spring.

Do your best to keep your windows closed during allergy season. When you come in from outdoors, it can also help to change your clothes or take a shower, especially before getting in bed. 

Neti pots

A neti pot, or a container you can use to rinse your nasal passages, can help relieve your allergy symptoms.

You fill the device with distilled water and salt to create a saline solution, then use it to clear out mucus and allergens in your mucus membranes. 

Neti pots can relieve congestion, runny nose, and other nasal symptoms, but if you still feel tired, it may help to take an allergy medication as well. 

Take medication at night

There are several over-the-counter (OTC) medications that can help manage your allergy symptoms, including fatigue.

Antihistamines, the most common OTC allergy medication, work by blocking the effects of histamines, which stops the inflammation in your body and your allergy symptoms.

Common antihistamines include: 

  • Diphenhydramine (Benadryl)
  • Fexofenadine (Allegra)
  • Loratadine (Alavert and Claritin)
  • Cetirizine (Zyrtec)
  • Clemastine (Tavist)
  • Chlorpheniramine (Chlor-Trimeton)

While diphenhydramine is the medication most commonly linked with sleepiness, it’s possible for other allergy medications to cause fatigue, too.

If you think your antihistamine is making you tired, try taking your medication at night.

The drug should still control your symptoms during the day, but talk to your doctor if you still feel tired during waking hours. You may need a different medication. 

Consider allergy shots

If over-the-counter allergy medications aren’t helping you enough, your doctor may recommend allergy shots, or regular injections that can help reduce allergic reactions. 

Also called immunotherapy, allergy shots work by introducing your body to a very small amount of the substance that causes your allergies.

Over time, your body will get used to the allergen, which can help control your symptoms. 

Visit an allergist

A primary care provider can help with mild or moderate allergy symptoms, but if allergic reactions are interfering with your day-to-day life, then you may want to see an allergist, who specializes in diagnosing and treating allergies. 

An allergist can help you identify what you’re allergic to through a skin or blood test, and then recommend the best treatment to help reduce your allergy symptoms (including how to best avoid your trigger). 

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When to See a Doctor

If you have allergy symptoms but over-the-counter medications aren’t helping you feel better, then it’s important to see a doctor.

Your primary care provider or an allergist can help you identify what’s causing your allergies, how to avoid triggers, and medication or other treatments that might help. 

While mild or moderate allergies aren’t considered a medical emergency, an allergy may cause a severe reaction called anaphylaxis.

Call 911 or go to the emergency department right away if you experience any of the following signs of an anaphylactic reaction: 

  • Skin reactions, such as hives, flushing, or itching
  • Swollen tongue or throat
  • Wheezing and difficulty breathing
  • Low blood pressure
  • Nausea, vomiting, or diarrhea 
  • Dizziness or fainting 
  • Weak, rapid pulse

How K Health Can Help

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Frequently Asked Questions

What kind of allergies make you tired?
Any type of allergic reaction can make you tired. When you come in contact with a substance you’re allergic to, your body responds with inflammation, which may make you feel more fatigued than usual.
Can allergies cause fatigue and body aches?
You may experience fatigue and body aches due an allergic reaction, which causes inflammation throughout your body. If you have allergies, you’ll also likely experience symptoms like sneezing, runny or stuffy nose, and itchy or watery eyes. Allergy symptoms usually resolve with medication. If you still have fatigue and body aches, it’s possible you may have an infection, such as a sinus infection, the flu, the common cold, or COVID-19.
Can seasonal allergies cause extreme fatigue?
Seasonal allergies can cause fatigue, but if you’re experiencing extreme fatigue that doesn’t go away when you treat the allergies, speak to a healthcare provider. Your doctor may want to rule out other causes of fatigue, including infection.
K Health articles are all written and reviewed by MDs, PhDs, NPs, or PharmDs and are for informational purposes only. This information does not constitute and should not be relied on for professional medical advice. Always talk to your doctor about the risks and benefits of any treatment.

Andrew Yocum, MD

Dr Andrew Yocum is a board certified emergency physician. He graduated Summa Cum Laude from Kent State University with a Bachelor of Science in Molecular Biology before attending Northeast Ohio Medical University where he would earn his Medical Doctorate (MD).

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