Allergies – Diagnosis, Symptoms, and Treatment

Doctor Nathan LeDeaux, MD

Medically reviewed by Dr. Nathan LeDeaux, MD

Medical Professional

Updated - December 9, 2020

Nathan LeDeaux is an emergency medicine physician at the University of Wisconsin and got his M.D. from Northwestern University in Chicago Illinois.

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What are Allergies?

Allergic rhinitis is a medical term for nasal allergies, sometimes called hay-fever.  It is an extremely common condition that affects millions of Americans and is one of the most common reasons patients see their primary care doctor. The condition can affect any age group including children, adolescents, and adults.

People usually have recurrent symptoms of a runny nose, nasal congestion, sneezing, and post-nasal drip (which may lead to chronic cough). While usually mild, these symptoms can be very bothersome and may reduce the quality of life and productivity. Symptoms usually occur during certain seasons of the year such as spring (seasonal allergic rhinitis), but in some individuals, symptoms may occur throughout the entire year (perennial allergic rhinitis).

What Causes Allergies?

Allergic rhinitis is usually caused by allergens in the environment such as:

  • Pollen
  • Grass
  • Pet dander
  • Dust mites
  • Insects (cockroaches)
  • Mold

Depending on what is triggering the allergies, symptoms may occur during a particular season (e.g., spring), in certain environments (e.g., home or work), or after exposure to certain breeds of pets.  Allergens enter the nasal passage and promote the release of histamine.  Histamine is a molecule that promotes inflammation and mucous secretion, resulting in swelling of the nasal passages and nasal congestion. The release of histamine in the nose can affect other areas of the body as well. Both redness of the eyes and the formation of dark bags beneath the eyes are commonly related to the release of histamine. 

Inflammation in the nasal passage also results in the runny nose seen in almost all people with allergies. This mucous also drains through the back of the nose into the throat (postnasal drip).  Which leads to frequent clearing of the throat and cough.  Symptoms can worsen if individuals are exposed to cigarette smoke, environments with a large amount of mold, or houses with multiple pets that shed dander.

How Common are Allergies?

Allergic rhinitis affects an estimated 20 to 40 million people in the United States.  This may be an underestimate since this condition is not life-threatening and many individuals do not seek medical treatment for their symptoms.  In fact, patients frequently treat themselves with over-the-counter medications.

Signs and Symptoms

Symptoms of allergic rhinitis can be similar to the common cold.  The most common symptoms of allergic rhinitis include the following:

  • Runny nose
  • Nasal congestion
  • Sneezing & nasal itching
  • Postnasal drip
  • Throat clearing & cough

Signs of allergic rhinitis include swollen nasal passages, clear mucous drainage from the nose, and a finding called “cobblestoning” on physical examination.  Cobblestoning is a change in the appearance of the back of the throat that occurs due to long-term inflammation that activates the lymphatic system leading to enlargement of the lymph nodes.  Enlarged lymphatic tissues in the mouth have raised appearances that resemble cobblestones, hence the term cobblestoning. These lymphatic tissues can also be enlarged in the neck, behind the ears, and at the back of the head. This can lead to an uncomfortable sensation of pressure or tightness in these areas in patients with severe allergies.

People with allergies tend to have other symptoms associated with allergic rhinitis, such as eye allergies (allergic conjunctivitis), asthma, and hives (allergic rash).


Allergic rhinitis is a clinical diagnosis, meaning your doctor can diagnose it based on your symptoms and signs on physical examination alone.  There are no specific tests that are needed to make the diagnosis.

Sometimes, if your symptoms are severe, your doctor will order skin or blood allergy tests to determine if you are a candidate for specialized immunotherapy. These treatments can further reduce the severity of your symptoms and may work even if over the counter treatments fail.

Allergy Medicine and Treatment

The treatment of allergic rhinitis includes avoiding allergens, medical therapy, and occasionally immunotherapy.

The first-line treatment of allergic rhinitis is a class of medications called intranasal corticosteroids.  Corticosteroids reduce inflammation, which is the main cause of runny nose, nasal congestion, and post-nasal drip.  There are various types of intranasal corticosteroids and now some of these agents are available over-the-counter.  The most common intranasal corticosteroids include:

These medications can start working within hours, but their maximal effectiveness occurs after 1-2 weeks of daily or twice-daily use. For this reason, most physicians will recommend that you use these medications daily during the season your allergies are most severe. 

Intranasal corticosteroids are usually very well tolerated side-effects are very rare and are generally limited to the nose and mouth. Some of these side effects include:

  • Bloody nose
  • Perforation of the nasal septum
  • Oral candidiasis (yeast infection of the mouth)

These complications are rare and are generally only seen in those who use these medications excessively. If you develop bleeding from the nose that does not resolve with light pressure you should discontinue the use of these medications and contact your physician. 

In young children use of these medications for multiple months at a time has resulted in low bone density and changes in bone growth. Ask your pediatrician prior to using these medications in children for an extended period of time.


An alternative to intranasal corticosteroids are intranasal antihistamines.  The most common intranasal antihistamine is Astelin (azelastine).  As we mentioned, histamine is released in the nasal passages in response to allergens and promotes inflammation.  Therefore, intranasal antihistamines reduce the ability of histamine to start the inflammatory process, decreasing nasal inflammation and the symptoms of allergic rhinitis.

In addition to intranasal medications, individuals with allergic rhinitis may benefit from oral antihistamines.  These include:

Oral antihistamines are frequently combined with intranasal corticosteroids if corticosteroids alone are not effective in reducing symptoms.  Some antihistamines (e.g., Benadryl and sometimes Zyrtec) can cause drowsiness; therefore, these medications should be avoided when working, driving, or operating heavy equipment.  These medications should also be avoided in elderly individuals as they can lead to confusion and increase the risk of falls.

Less commonly, medications such as Cromolyn or a class of drugs called leukotriene receptor antagonists may be recommended. These medications are prescription only and have various side effects that make them appropriate only for patients with severe symptoms.

If your symptoms do not respond to the medications we have discussed so far, your doctor may prescribe a short course (1-2 weeks) of oral corticosteroids such as Prednisone or Solumedrol (e.g., Medrol dose pack).  Long-term treatment with oral corticosteroids should be avoided as it can lead to weight gain, changes in mood or behavior, suppression of the immune system, diabetes, and osteoporosis.

Lastly, patients with severe allergies may benefit from seeing an allergist and receiving immunotherapy to decrease their allergic response to environmental allergens that trigger their symptoms. This process involves identifying which allergens the body is reacting to and reducing the severity of that reaction by continually exposing the body to large amounts of that allergen. 


  1. Sur DK, Plesa ML. Treatment of allergic rhinitis. Am Fam Physician. 2015 Dec 1;92(11):985-92. -
  2. Klimek L, Mullol J, Hellings P, et al. Recent pharmacological developments in the treatment of perennial and persistent allergic rhinitis. Expert Opin Pharmacother. 2016;17(5):657-69. -
  3. Stewart MG. Identification and management of undiagnosed and undertreated allergic rhinitis in adults and children. Clin Exp Allergy. 2008 May;38(5):751-60. -


The above information is an educational aid only. It is not intended as medical advice for individual conditions or treatments. Talk to your doctor, nurse or pharmacist before following any medical regimen to see if it is safe and effective for you.