When patients with oral allergy syndrome take angiotensin-converting enzyme (ACE) inhibitors for hypertension and congestive heart failure, they are at an increased risk for a life-threatening allergic reaction known as anaphylaxis.
The case studies, being presented at the Annual Scientific Meeting of the American College of Allergy, Asthma and Immunology (ACAAI), found use of ACE inhibitors can cause what is known as a "priming effect" in oral allergy syndrome sufferers.
"When a sufferer's allergies are primed and they come in contact with a particular allergen, they experience a more severe than normal reaction," said allergist Denisa Ferastraoaru, MD, ACAAI member and lead study author. "Symptoms can include extreme facial swelling (angioedema) and difficulty breathing, which can lead to death in some cases."
Hay fever sufferers that experience an itchy mouth or scratchy throat after eating certain raw fruits or vegetables and some tree nuts, may have oral allergy syndrome. It is also known as pollen-food syndrome, since it is caused by cross-reacting allergens found in both pollen and raw produce.
"Sufferers can often mistake oral allergy syndrome symptoms for food allergy," said allergist David Rosenstreich, MD, ACAAI fellow and study author. "But it isn't a food allergy, and often patients can eat that food when it is cooked. For example, an individual may have a reaction to a raw apple but not to apples baked in a pie."
When allergists advised patients to avoid raw produce and switched from ACE inhibitors to angiotensin II receptor blocker (ARB) therapy, no further oral allergy symptoms occurred.
Not everyone with a pollen allergy will experience oral allergy syndrome when eating raw produce and tree nuts. However, the syndrome is commonly associated with these allergens:
• Birch Pollen: apple, almond, carrot, celery, cherry, hazelnut, kiwi, peach, pear, plum
• Grass Pollen: celery, melons, oranges, peaches, tomato
• Ragweed Pollen: banana, cucumber, melons, sunflower seeds, zucchini
While oral allergy symptoms are typically mild, including mouth and throat discomfort, swelling and itching, it is important sufferers discuss these symptoms with their allergist because anaphylaxis can sometimes occur.