January 19, 2018 | Black & Kletz Allergy
Exercise-induced anaphylaxis (EIA) is defined as the onset of allergic symptoms during, or immediately after, exercise. The manifestations may include hives (i.e., urticaria), swelling of the soft tissues (i.e., angioedema), generalized itching (i.e., pruritus), wheezing, shortness of breath, nausea, dizziness, fainting, and/or a drop in blood pressure. In some individuals, these reactions occur only if exercise is undertaken after eating certain specific foods! When the food intake and the exercise are independent of each other, there are no symptoms. This condition is termed “food-dependent exercise Induced anaphylaxis” (i.e., FDEIA).
Symptoms of FDEIA may begin at any stage of exercise and occasionally occur just after exercise. The offending food is usually ingested within 4 hours preceding exercise, or rarely just after exercise. The frequency with which symptoms occur varies among patients with FDEIA and can be very unpredictable, even for a given patient. Early signs and symptoms may include fatigue, diffuse warmth, flushing, and/or generalized itching. These symptoms usually subside after some time if the person stops exercising. If the exercise is continued however, it can lead to swelling of the throat, breathing difficulty, drop in blood pressure, and vascular collapse which can potentially be fatal.
Though a wide variety of foods are known to play a role, the most common foods which have been observed to cause this condition are grains (especially wheat) and nuts in Western populations and shellfish in Asians. Most patients develop symptoms only after eating a specific food, although a few have attacks if any food (usually solids rather than liquids) has been ingested. Patients have been described where symptoms occurred only if 2 foods were eaten together before exercise. The processing of the food(s) may also be critical in some cases, such as a patient who developed FDEIA with tofu but could tolerate soy milk.
The exact mechanism of how food plus exercise triggers life-threatening reactions is not clearly known. A leading theory suggests that physical exertion enhances the absorption of the food from the gut. Ingestion of alcohol can also facilitate this condition, probably by the same mechanism. Another hypothesis suggests that exercise stimulates the mast cells (which are previously sensitized to specific food proteins) to release chemical mediators responsible for the reaction. In some instances, taking medications such as aspirin or nonsteroidal anti-inflammatory drugs [(e.g., Motrin, Advil (ibuprofen), Aleve (i.e., naproxen)] can also contribute to the reaction, supporting the hypothesis of mast cell activation.
As mentioned above, wheat is the most commonly reported allergen in FDEIA overall. Gliadin, a protein component of gluten, is an important allergen in this disorder, as well as in wheat allergy causing anaphylaxis independent of exercise.
DIAGNOSIS:
The following criteria are needed to establish the diagnosis of FDEIA:
- Signs and symptoms consistent with anaphylaxis that occurred during (or within 4 hours of) exercise but only when exercise was preceded by food ingestion.
- No other diagnosis that explains the clinical presentation.
If a specific food is implicated, there should be:
- Evidence of a specific antibody to the implicated food, either by skin tests or by blood tests and
- No symptoms on ingestion of that food in the absence of exertion and no symptoms if exercise occurs without ingestion of that food, although there may be rare exceptions (i.e., patients may report isolated incidences when symptoms occurred at rest in the presence of other exacerbating factors, such as illness).
A serum tryptase level should be measured in all patients and should be normal in individuals with FDEIA when the patients are in their usual state of health. Elevated levels at baseline should prompt an evaluation for a mast cell disorder.
Skin testing or blood testing for environmental allergens is sometimes useful if the patient is more susceptible to attacks during certain pollen seasons or in a patient with concomitant allergic respiratory disease such as asthma.
A positive food plus exercise challenge confirms the diagnosis, but a negative challenge does not reliably exclude the diagnosis because symptoms can be difficult to induce in a laboratory setting and the procedure is not standardized.
TREATMENT:
Avoidance of ingesting the suspected food before exercising is critical. Identification of aggravating factors such as alcohol, aspirin, and/or nonsteroidal anti-inflammatory drugs and their avoidance is also important.
- Always carry an epinephrine self-injectable device (e.g., EpiPen, Auvi-Q, Adrenaclick) and mobile phone in all exercise settings. If the epinephrine is ever used, always go immediately to the closest emergency room.
- Stop exertion immediately if any symptoms occur (never “push through”).
- Avoid the causative food for at least 4-6 hours before exercise.
- Always exercise with other informed individuals.
In some individuals with this condition, pre-treatment with certain medications such as first generation antihistamines and/or cromolyn may provide some preventive benefit. It should be noted that this is not a substitute for avoidance of eating the allergic food and then exercising.
The board certified allergists at Black & Kletz Allergy will promptly respond to any questions regarding FDEIA and other allergic or immunologic disorders. We have been treating this condition for many years and have offices in Washington, DC, McLean, VA (Tysons Corner, VA), and Manassas, VA. We have been serving the Washington, DC, Northern Virginia, and Maryland metropolitan area for over 50 years and treat both adult and pediatric patients. All 3 offices at Black & Kletz Allergy offer on-site parking and the Washington, DC and McLean, VA offices are Metroaccessible. There is a free shuttle that runs between our McLean, VA office and the Spring Hill metro station on the silver line. If you are concerned that you may have FDEIA or any other allergy, asthma, sinus, skin, or immunology problem(s), please call us to schedule an appointment. You may also click Request an Appointment and we will reply within 24 hours by the next business day. At Black & Kletz Allergy, we strive to improve the quality of life in allergic individuals in a professional and caring setting.
