The ultimate guide to seasonal allergies

Reviewed by:
Dr. Robert Kwok
Director of Health Informatics
Last updated on April 6, 2022 UTC

Experts estimate that 1 in 6 Americans suffer from allergies, making it one of the most common health issues in the country. Many people self-treat for symptoms like sneezing and coughing using over-the-counter allergy medicine, without seeking professional guidance first. 

However, working with a medical professional instead of going the trial and error route to find which allergy medicine works best offers a significant advantage.

Let’s talk about the basics of allergies, including triggers, symptoms, and the different methods used to treat them.

Why do allergies occur?

An allergic reaction happens when the body encounters a normally harmless substance, like pollen or pet dander. Instead of dismissing it as a non-threat, the immune system overreacts and marks it as a dangerous invader. 

Once the body has tagged that allergen as foreign material, the immune system does everything it can to remove it. The first step of the removal process involves creating a type of protein known as an antibody.

Antibodies help keep the body safe — in fact, one of their primary jobs is to be constantly on guard for invaders. If an antibody detects an invader, it reacts by triggering the release of chemicals (known as histamines) that help remove those invaders from the body. 

Histamines are the leading trigger of many classic allergy symptoms, like sneezing, watery eyes, and itching (which are the exact mechanisms that help expel allergens from the body!). 

Allergy triggers

The immune system can react to any substance as an allergen. However, some substances are far more likely to trigger allergies. These allergies can occur just once, year-round, or seasonally.

  • Drugs
    While true drug allergies are rare, penicillin is the most common.

  • Food
    According to the FDA, the eight most common food allergens are cow’s milk, eggs, fish, peanuts, tree nuts, shellfish, soybeans, and wheat.  

  • Insects
    Both stinging (bees, wasps) and non-stinging (cockroaches, dust mites) insects can trigger an allergic reaction.
  • Latex
    Latex is present not only in gloves but also in balloons, condoms, and some clothing. 
  • Mold
    Mold allergies can occur inside and outside the home.
  • Pets
    Cats, dogs, and even small animals like rabbits and birds can all shed dander, which is what causes the allergy. 
  • Pollen
    The most common trigger of seasonal allergies, which is sometimes called “hay fever.” 

Common allergy symptoms

Allergy symptoms are most prominent in the parts of the body that encounter the allergen. 

For example, allergens that people breathe in (like pollen) trigger respiratory symptoms like sneezing. On the other hand, food allergens are more likely to produce a GI reaction. 

However, medical professionals see a few common symptoms most frequently. 

For instance, respiratory allergy signs and symptoms often include:

  • Congestion (stuffy nose);

  • Dry cough;

  • Itching of the eyes, nose, or roof of the mouth;

  • Runny nose;

  • Shortness of breath;

  • Sore throat;

  • Sneezing;

  • Watery eyes;

  • Wheezing.

These symptoms can easily mimic the symptoms caused by respiratory viruses, like the common cold. Because of this, people with suspected allergies should have them diagnosed by a doctor before attempting home treatment. 

In addition, although people frequently refer to respiratory allergies as “hay fever,” fever is not a symptom of allergies. Developing a fever can indicate a different issue outside of an allergic reaction, which often needs to be evaluated by a doctor. 

Other signs and symptoms of an allergy flare-up include (but are not limited to):

  • Fatigue;

  • Headache;

  • Hives;

  • Itching of the skin;

  • Nausea and vomiting (common with food allergies);

  • Redness or a localized rash;

  • Tingling in the mouth.

Any person with allergies should also know that, although rare, any allergen can trigger an anaphylactic reaction. Symptoms like loss of consciousness, severe shortness of breath, or swelling of the lips, mouth, neck, and throat are considered a medical emergency.

Which allergy medicine works best?

Everyone’s experience with allergies is different. Which allergy medicine works best depends on which medicine most effectively controls their specific symptoms. 

Anyone looking to manage their allergies should discuss their current medications and diagnoses with their primary care doctor or allergist before starting treatment — this will help them get the best guidance on which medicines may be most effective for them specifically. 

Allergy medicine comes in a few different forms, each with a slightly different method of action. Some are available as over the counter allergy medicine, while others need to be prescribed by a medical professional.


Because histamines are the main substance that triggers allergy symptoms in the body, many effective allergy medicines offer a way to counteract their effects. These medications are known as antihistamines. 

Common oral antihistamines include Benadryl (diphenhydramine) and Zyrtec (cetirizine). 

A frequent side effect of these over-the-counter allergy medicines is drowsiness, especially diphenhydramine. People using them to manage allergy symptoms should use caution when driving or operating heavy machinery.   

There are also antihistamines (and related medications) that allergy sufferers can use nasally. Some, like Nasalcrom (cromolyn), are available over the counter. Others require a doctor's prescription, including Astelin (azelastine).


Doctors may recommend a decongestant for temporary but immediate relief from allergy symptoms. While they are primarily available as over-the-counter allergy medicine, they also come with significant potential side effects. 

Because of this, people considering them (especially those with a pre-existing diagnosis of high blood pressure or cardiovascular disease) should always consult with a primary care provider before starting.

Common medications in this category include oral tablets like pseudoephedrine (Sudafed) and nasal sprays like Afrin (oxymetazoline). Using decongestant nasal sprays for three days back to back may worsen congestion instead of reducing. It’s important to follow provider guidelines to reduce the risk of this “rebound congestion”.


To help with allergy-related inflammation, doctors may also suggest corticosteroids. This category of medication has options for use nasally, orally, or inhaled. 

As a whole, corticosteroids work to reduce congestion, runny nose, itching, and wheezing but may take up to a week to work. Many also require a doctor’s prescription due to the potential for significant side effects. 

Common corticosteroids include nasal options like Flonase (fluticasone propionate) and Nasonex (mometasone).

Doctors may prescribe certain medications, like Medrol (methylprednisolone), as a temporary way to help manage particularly severe allergy symptoms. These allergy medications are short-term and only available by prescription, as long-term use may lead to muscle weakness, osteoporosis, and stomach ulcers. They may also elevate blood pressure, especially in those with pre-existing issues.

Many topically-applied skin allergy medicines, like triamcinolone, also fall into the corticosteroid category.

Leukotriene inhibitors

In response to an allergen, the body also releases a chemical called leukotriene. One of the most popular allergy medications, Singulair (montelukast), works to block the action of leukotriene to help address asthma symptoms

However, these medications can also trigger some psychological symptoms, like difficulty sleeping, anxiety, and depression. 

In addition, leukotriene inhibitors work best when taken every day, even when patients are not experiencing symptoms. Instead of stopping symptoms that have already started, these medications can help keep the body from reacting in the first place. 

Other ways to manage allergies

In addition to learning which allergy medicine works best, people with allergies should also consult their doctor about other ways to manage their symptoms outside of OTC options. 

Primary providers may recommend a referral to an allergist. Allergists can perform tests that can help determine what allergens are triggering the reaction, and with that information, patients can work to avoid their triggers, if possible, or can explore other options for symptom management. 

Allergy injections

If conservative allergy medicines don’t help with symptoms, the next step is often allergen immunotherapy

While prescription and over-the-counter allergy medicines can manage symptoms that occur with exposure, allergen immunotherapy exposes patients to those allergens strategically to train the body not to overreact. 

The most common way that doctors administer allergen immunotherapy is via injection. The shots contain a small amount of the allergen, and the patient will need to go into the office to receive the injections once or twice a week. The dose increases every week or two according to the patient’s progress.

Once the dose has reached maximum effectiveness, doctors recommend continuing injections every two to four weeks. Year-round injections of allergen immunotherapy help patients maintain increased tolerance, often preventing allergy symptoms entirely. 

Lifestyle changes

Managing symptoms may also involve lifestyle changes, especially for those with seasonal allergies. 

Staying inside on dry, windy days, wearing a mask if the pollen count is high, or even rescheduling plans if necessary can help keep allergens (and symptoms) at bay. Showering after spending time outdoors can also help to reduce the likelihood or severity of allergy symptoms. 

To summarize

Although there is no “cure” for allergies, symptoms are usually very manageable with doctor-guided care and treatment. 

The affordable virtual care team at HealthTap can help guide allergy sufferers through their options, whether that is an over-the-counter allergy medicine or prescription. If recommended, they can also make referrals for allergy testing, all done from the comfort and privacy of home.

Schedule an appointment with a HealthTap provider today, or explore our Allergies guide for more helpful info.


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