Allergy, Rhinitis, and Migraine Headache

 

 
 Allergy, Rhinitis, and Migraine Headache
Vincent Martin, MD
 
Key Points:
  1. Allergic rhinitis increases the likelihood of having migraine headache and may also influence the frequency of attacks. 
  2. An allergic rhinitis diagnosis requires a positive allergy test. It also requires the presence of symptoms of rhinitis (e.g. sneezing, post nasal drip, runny nose, nasal congestion) upon exposure to that allergic substance. Just because you have positive allergy tests does not mean that you have allergic rhinitis. 
  3. Only specific testing for allergies establishes a diagnosis of allergy.
  4. Early evidence suggests that the avoidance of food allergens may decrease the frequency of migraine attacks in some patients. 
  5. Few studies exist to determine if treatment of allergic rhinitis improves migraine headache. 
Introduction
It is easy to get the wrong idea about the relationship between allergy, rhinitis and migraine headaches.  This is true more than for almost any other topic. Various viewpoints exist due to the fact that migraine headaches are diagnosed in 86-88% of patients reporting “sinus headaches”.  Sinus headaches are not an official diagnosis within the field of headache.  Patients and providers often define sinus headaches by pain and pressure over sinus areas. Sinus symptoms such as congestion or runny nose happen in nearly half of all migraine attacks. This association between sinus and migraine headache leads many headache experts to believe that allergy and rhinitis play no role in provoking attacks of migraine headache.  Recent research suggests this may not be correct.
 
Confirming allergy - Tests
Tests performed by your allergist, ENT or primary care provider can confirm allergies. These tests include skin testing and blood work. Skin tests are the most common. Skin prick tests use tiny amounts of allergens (e.g. cat hair, dust, mold, and pollens) placed on the skin. For a large number of tests the tester uses the back. Testers also use the forearm or upper arm. The tester then pricks or stabs the skin so the allergen goes under the skin surface. A positive is development of an allergic reaction. This reaction is usually swelling and redness at the site. Positive results usually occur within 15-20 minutes. An intradermal skin test involves an injection of allergen under the skin. TB (tuberculosis) skin testing is an example. It is less reliable for allergies due to many false positives. Lastly, allergens taped to the skin produce a skin reaction in 24 to 48 hours similar to that seen with the other methods.  Blood work measures protein levels to identify specific allergies.  These are antibodies to a specific allergen. These tests are called RAST or immunocap tests. 
                                   
Food allergens are identified by positive skin prick testing or blood work.  Once food allergens have been identified it is necessary to undergo a food elimination diet to confirm that it is causing headaches. This involves the removal from the diet of presumed food allergens causing symptoms. They are then added back typically one by one. If symptoms improve with elimination and reoccur with reintroduction of the food then you have a true food allergy.
 
How common are allergies?                                                                                  
One or more positive allergy tests indicate that a person is “allergic”.  Thirty to forty percent of the public has one or more positive allergy tests if they undergo allergy testing. 
 
What is allergic rhinitis?
A positive allergy test in a person with rhinitis does not mean that person has allergic rhinitis.  Patients with allergic rhinitis must have allergies noted on allergy testing. They must also have rhinitis symptoms such as sneezing, nasal congestion, runny nose or post nasal drip. These symptoms must occur when exposed to the allergen. For example, if a patient had a positive allergy test to cat hair and experienced rhinitis symptoms when exposed to cats then the patient has allergic rhinitis.  One in five people in the United States have allergic rhinitis.   
 
Migraine and allergic rhinitis
Several studies report that migraine headaches are more common with allergic rhinitis than in those without the diagnosis.  One study found that migraine headache occurred in 34% of those with allergic rhinitis. Only 4% of patients without allergic rhinitis had migraine.  Other studies have found that migraine headache is 2-3 times more common with a diagnosis of allergic rhinitis.
                                                                                                                                     
Allergic rhinitis might also affect the frequency of attacks.  Health care spending for the treatment of migraine headache tends to increase during allergy seasons.  A recent allergic rhinitis study found a dramatically increased frequency of migraine headaches in patients younger than 45 years of age with greater than half of their allergy tests positive. The peak time for development of allergies is under age 45. This could suggest that allergy provokes migraine most when there are lots of allergies and plays a greater role in younger than older patients. 
 
Migraine and food allergies
Several small studies have shown that avoidance of foods allergens leads to a decrease in the frequency of migraine headache.   A recent study conducted in 30 patients found that avoidance of foods to which they were allergic reduced migraine attacks by 29%. There are several problems however with use of diets to avoid food allergens. Testing of food allergens often involves 200 or more foods. As a result positive tests are common. This leads to elimination of many foods from the diet.  In fact, one study identified 24 avoided foods per individual.  Removal of all the possible food allergies from ones diet can often prove quite challenging. Many of the positive food allergy tests are staples of the Western diet (e.g. wheat, dairy, eggs, seafood, and nuts). It can be difficult to avoid these for long periods of time. Total avoidance of all of these foods typically leads to a nutritionally unhealthy or unbalanced diet.  Therefore, one should speak with a healthcare provider or dietician before starting such a diet. 
 
How might allergies provoke migraine attacks?
There are several ways that allergy could affect migraine headache.  First, there is an association between inflammatory reactions and allergies. The inflammatory reaction causes the release of chemicals such as histamine, prostaglandins, leukotrienes and serotonin. Leukotrienes are fatty molecules of the immune system of interest here because they contribute to inflammation in asthma and allergic rhinitis. All of these chemicals can trigger migraine headaches.  Second, allergic rhinitis leads to nasal congestion. This could activate nerves in the nose that could provoke attacks of migraine headaches.  In addition, nasal congestion makes it difficult to breath at night, which might lead to sleep apnea that could cause headache.  Third, allergy worsens symptoms of depression and anxiety.  This could affect the number of migraines and the way that they are experienced. Research shows that patients with depression compared to those without depression perceive their migraine attacks as more severe and disabling.  With improvement of depression headache severity and disability also improve.
 
Treatment of allergies for headache
Few studies exist to determine if the treatment of allergies or allergic rhinitis decreases the frequency of migraine headache.  Nasal steroids decrease symptoms of obstructive sleep apnea that can lead to headaches upon awakening.  Monteleukast or Singular® is a leukotriene inhibitor or blocker used as an asthma and rhinitis medication. The largest migraine study assigned patients to receive daily monteleukast or placebo (sugar pills) for several months.  It did not prevent migraines, but was not specifically studied in migraine subjects with rhinitis or in those with allergies. Therefore, its effect on migraine headache in allergic rhinitis patients is uncertain. Anecdotally, the author has noted some improvement of headaches in patients with allergic rhinitis with use of nasal steroids, antihistamines and monteleukast. However, the response is quite variable in clinic patients.                     
 
Allergy shots are injections of small dosages of allergens given on a weekly basis to decrease allergy symptoms.  Early studies from the 1960s and 1970s found that allergy shots reduce headache attacks (not migraines) in patients with allergies to dust, pollens and cats.   A more recent study in patients with allergic rhinitis found a 50% reduction in the frequency of attacks of migraine in patients receiving allergy shots as compared to those not receiving shots.  Most of the studies had small numbers of patients and none randomly assigned patients to allergy shots or placebo (sugar pills).  Therefore, these results are preliminary and we do not currently recommend allergy shots for the treatment of headache disorders till more studies are done. 
 
Summary
Allergic rhinitis increases the likelihood of having migraine headache and may also influence the frequency of attacks.  Early evidence suggests that the avoidance of food allergens may decrease the frequency of migraine attacks in some patients.  There are few studies to determine if treatment of allergic rhinitis improves migraine headache.
 
Vincent Martin, MD,  Professor of Medicine, University of Cincinnati, Division of General Internal Medicine, Cincinnati, OH.
 
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