Exercise-induced Anaphylaxis

Anaphylaxis is a relatively common occurrence for many adolescents. As primary care doctors, we normally see the patient after the acute phase, and then are required to do the detective work to figure out the causes of the episode. The cause may be obvious, but many times we have to hope for another occurrence with similar circumstances to identify it. Surprisingly, the cause may not be what you think. Factors that contribute to an anaphylaxis response may be related to activity, timing of food ingestion, an environmental factor, or medication.

Let’s look at just one type, exercise-induced anaphylaxis. It’s divided into two categories: food dependent and nonfood dependent. Both are described as an induction of itching, urticaria, and fatigue, with progression to angioedema and hypotension, associated with exercise (J. Allergy Clin. Immunol. 1980;66:106-11).

Food-dependent exercise-induced anaphylaxis occurs when exercise is started 30 minutes after ingesting food. This may be difficult to identify because patients react to the food only if they exercise, so food is usually eliminated as a cause. Wheat and wheat flour are common culprits for this type of reaction because of the omega-5 gliadin, which is the protein in gluten (J. Allergy Clin. Immunol. 1991;87:34-40). In one study, larger amounts of the suspected agent were given; hives and angioedema did start to occur in 20% of patients challenged, which suggested that there was likely a baseline allergy to the food, and exercise itself might be a cofactor in augmentation of the allergic reaction.

In nonfood-dependent exercise-induced anaphylaxis, symptoms of itching, urticaria, and fatigue can occur 5-30 minutes after the start of exercise. Although bronchospasm is rare, it can occur along with angioedema, nausea, vomiting, and hypotension, and can even be fatal if exercise continues. If exercise is stopped, it usually resolves. However, many people try to push through it, which only worsens the symptoms.

Cofactors associated with nonfood-dependent exercise-induced anaphylaxis are ingestion of alcohol and an NSAID several hours beforehand. These agents also might be overlooked if well tolerated independently (Br. J. Dermatol. 2001;145:336-9).

Timing of the episode also plays a role. Premenstrual syndrome can be a factor in augmentation of anaphylaxis, so it also should be considered. Knowing the date of the last menstrual cycle and identifying if the anaphylaxis is episodic will identify premenstrual syndrome as a cause.

The work-up should include standard allergy testing and determination of tryptase levels. Skin testing is essential to identify offending agents, and is rarely negative. If a food is suspected and skin testing is negative, repeat the skin testing in 6 months. In one study, wheat extract was found to be positive in only 29% of persons suspected of having a wheat allergy, but when the paste of wheat flour was tested, 80% were identified. The ImmunoCAP Test also was found to have a sensitivity of 80%, so it is a valuable test to try along with the skin prick.

Tryptase levels should be evaluated because in nonfood-dependent exercise-induced anaphylaxis, these levels are slightly elevated at the time of the anaphylaxis, but return to normal. A patient with mastocytosis, a group of disorders characterized by pathologic mast cells infiltrating the skin, will consistently have elevated tryptase levels. Seasonal allergies associated with pollen, and asthma bronchospasm also should be considered as causes.

Although these exercise-induced anaphylaxis episodes can occur at any age, they are most frequent in the adolescent age group, probably because that’s the time most of this population are involved in organized sports. Upon presentation, a careful detailed history will help to identify the cause of anaphylaxis and result in quicker resolution.

Treatment includes avoidance of the offending agent if identified and an antihistamine, and if symptoms do occur, ceasing exercise immediately to avoid a full-blown anaphylactic reaction.

Dr. Pearce is a pediatrician in Frankfort, Ill. 

Anaphylaxis is a relatively common occurrence for many adolescents. As primary care doctors, we normally see the patient after the acute phase, and then are required to do the detective work to figure out the causes of the episode. The cause may be obvious, but many times we have to hope for another occurrence with similar circumstances to identify it. Surprisingly, the cause may not be what you think. Factors that contribute to an anaphylaxis response may be related to activity, timing of food ingestion, an environmental factor, or medication.

Let’s look at just one type, exercise-induced anaphylaxis. It’s divided into two categories: food dependent and nonfood dependent. Both are described as an induction of itching, urticaria, and fatigue, with progression to angioedema and hypotension, associated with exercise (J. Allergy Clin. Immunol. 1980;66:106-11).

Food-dependent exercise-induced anaphylaxis occurs when exercise is started 30 minutes after ingesting food. This may be difficult to identify because patients react to the food only if they exercise, so food is usually eliminated as a cause. Wheat and wheat flour are common culprits for this type of reaction because of the omega-5 gliadin, which is the protein in gluten (J. Allergy Clin. Immunol. 1991;87:34-40). In one study, larger amounts of the suspected agent were given; hives and angioedema did start to occur in 20% of patients challenged, which suggested that there was likely a baseline allergy to the food, and exercise itself might be a cofactor in augmentation of the allergic reaction.

In nonfood-dependent exercise-induced anaphylaxis, symptoms of itching, urticaria, and fatigue can occur 5-30 minutes after the start of exercise. Although bronchospasm is rare, it can occur along with angioedema, nausea, vomiting, and hypotension, and can even be fatal if exercise continues. If exercise is stopped, it usually resolves. However, many people try to push through it, which only worsens the symptoms.

Cofactors associated with nonfood-dependent exercise-induced anaphylaxis are ingestion of alcohol and an NSAID several hours beforehand. These agents also might be overlooked if well tolerated independently (Br. J. Dermatol. 2001;145:336-9).

Timing of the episode also plays a role. Premenstrual syndrome can be a factor in augmentation of anaphylaxis, so it also should be considered. Knowing the date of the last menstrual cycle and identifying if the anaphylaxis is episodic will identify premenstrual syndrome as a cause.

The work-up should include standard allergy testing and determination of tryptase levels. Skin testing is essential to identify offending agents, and is rarely negative. If a food is suspected and skin testing is negative, repeat the skin testing in 6 months. In one study, wheat extract was found to be positive in only 29% of persons suspected of having a wheat allergy, but when the paste of wheat flour was tested, 80% were identified. The ImmunoCAP Test also was found to have a sensitivity of 80%, so it is a valuable test to try along with the skin prick.

Tryptase levels should be evaluated because in nonfood-dependent exercise-induced anaphylaxis, these levels are slightly elevated at the time of the anaphylaxis, but return to normal. A patient with mastocytosis, a group of disorders characterized by pathologic mast cells infiltrating the skin, will consistently have elevated tryptase levels. Seasonal allergies associated with pollen, and asthma bronchospasm also should be considered as causes.

Although these exercise-induced anaphylaxis episodes can occur at any age, they are most frequent in the adolescent age group, probably because that’s the time most of this population are involved in organized sports. Upon presentation, a careful detailed history will help to identify the cause of anaphylaxis and result in quicker resolution.

Treatment includes avoidance of the offending agent if identified and an antihistamine, and if symptoms do occur, ceasing exercise immediately to avoid a full-blown anaphylactic reaction.

Dr. Pearce is a pediatrician in Frankfort, Ill. 

Anaphylaxis is a relatively common occurrence for many adolescents. As primary care doctors, we normally see the patient after the acute phase, and then are required to do the detective work to figure out the causes of the episode. The cause may be obvious, but many times we have to hope for another occurrence with similar circumstances to identify it. Surprisingly, the cause may not be what you think. Factors that contribute to an anaphylaxis response may be related to activity, timing of food ingestion, an environmental factor, or medication.

Let’s look at just one type, exercise-induced anaphylaxis. It’s divided into two categories: food dependent and nonfood dependent. Both are described as an induction of itching, urticaria, and fatigue, with progression to angioedema and hypotension, associated with exercise (J. Allergy Clin. Immunol. 1980;66:106-11).

Food-dependent exercise-induced anaphylaxis occurs when exercise is started 30 minutes after ingesting food. This may be difficult to identify because patients react to the food only if they exercise, so food is usually eliminated as a cause. Wheat and wheat flour are common culprits for this type of reaction because of the omega-5 gliadin, which is the protein in gluten (J. Allergy Clin. Immunol. 1991;87:34-40). In one study, larger amounts of the suspected agent were given; hives and angioedema did start to occur in 20% of patients challenged, which suggested that there was likely a baseline allergy to the food, and exercise itself might be a cofactor in augmentation of the allergic reaction.

In nonfood-dependent exercise-induced anaphylaxis, symptoms of itching, urticaria, and fatigue can occur 5-30 minutes after the start of exercise. Although bronchospasm is rare, it can occur along with angioedema, nausea, vomiting, and hypotension, and can even be fatal if exercise continues. If exercise is stopped, it usually resolves. However, many people try to push through it, which only worsens the symptoms.

Cofactors associated with nonfood-dependent exercise-induced anaphylaxis are ingestion of alcohol and an NSAID several hours beforehand. These agents also might be overlooked if well tolerated independently (Br. J. Dermatol. 2001;145:336-9).

Timing of the episode also plays a role. Premenstrual syndrome can be a factor in augmentation of anaphylaxis, so it also should be considered. Knowing the date of the last menstrual cycle and identifying if the anaphylaxis is episodic will identify premenstrual syndrome as a cause.

The work-up should include standard allergy testing and determination of tryptase levels. Skin testing is essential to identify offending agents, and is rarely negative. If a food is suspected and skin testing is negative, repeat the skin testing in 6 months. In one study, wheat extract was found to be positive in only 29% of persons suspected of having a wheat allergy, but when the paste of wheat flour was tested, 80% were identified. The ImmunoCAP Test also was found to have a sensitivity of 80%, so it is a valuable test to try along with the skin prick.

Tryptase levels should be evaluated because in nonfood-dependent exercise-induced anaphylaxis, these levels are slightly elevated at the time of the anaphylaxis, but return to normal. A patient with mastocytosis, a group of disorders characterized by pathologic mast cells infiltrating the skin, will consistently have elevated tryptase levels. Seasonal allergies associated with pollen, and asthma bronchospasm also should be considered as causes.

Although these exercise-induced anaphylaxis episodes can occur at any age, they are most frequent in the adolescent age group, probably because that’s the time most of this population are involved in organized sports. Upon presentation, a careful detailed history will help to identify the cause of anaphylaxis and result in quicker resolution.

Treatment includes avoidance of the offending agent if identified and an antihistamine, and if symptoms do occur, ceasing exercise immediately to avoid a full-blown anaphylactic reaction.

Dr. Pearce is a pediatrician in Frankfort, Ill.