Exercise-Induced Anaphylaxis Successfully Treated with Hydroxychloroquine

Rationale:  Exercise-induced anaphylaxis is a diagnosis that presents unique challenges for patients whose livelihood is dependent on their ability to physically exert themselves.  For patients refractory to suppressive antihistamine therapy and unable to practice avoidance, alternative treatment modalities are not well described.  We report a case of recurrent, exercise-induced anaphylaxis in a young man in the military, successfully treated with hydroxychloroquine.

Methods: After treatment failure with histamine blockade, a trial of hydroxychloroquine was performed.

Results: The patient is a 32 year-old man in the military who experienced several episodes of anaphylaxis associated with exercise. The typical episodes would occur during very strenuous anaerobic episodes, such as weight lifting, and involve cutaneous, gastrointestinal, and cardiovascular symptoms.  The usual causes of anaphylaxis, such as food allergy, medication reaction, mastocytosis, cholinergic urticaria, and food-exercise associated anaphylaxis were considered and systematically ruled out.  The patient did not improve with suppressive antihistamine therapy.  Two months after the addition of hydroxychloroquine 200 milligrams twice daily, the patient experienced no further anaphylactic reactions and was able to resume high-intensity exercise.  He will remain on hydroxychloroquine indefinitely.

Conclusions:  To our knowledge, we report the first case of exercise-induced anaphylaxis successfully treated with hydroxychloroquine.  Immunomodulatory therapy for exercise-induced anaphylaxis represents a novel strategy for treating these patients when they must continue to exercise.