Spirulina allergy; a case history of two patients

Abstract

Spirulina (derived from algae) is sold as a powder and marketed as a health supplement, offering plant-based protein. The following case report details two patients with suspected anaphylaxis to the product, the investigations performed and correlations between patients and past medical history. Two patients were reviewed in clinic in a 6-month period. Both had a past medical history of oral allergy syndrome with positive birch pollen components on component resolved testing (r BetV1) and seasonal rhinitis. No other significant atopy or past medical history. Both patients describe mild, oral reactions following some fresh fruit and vegetables, not to cooked versions. Similar interactions with spirulina; patients had added the powder to a morning smoothie and developed systemic allergic symptoms (generalized itching, burning in soles of feet, shortness of breath, urticaria) needing treatment. No adrenaline was used. One patient attended hospital and showed a dynamic mast cell rise. On assessment, these patients displayed positive skin prick test with the spirulina powder. 5 health control patients showed no response. Based on the clinical history and skin prick tests, we have diagnosed likely spirulina allergy and encouraged strict avoidance. Both patients have consumed all other smoothie ingredients since with no problems. Health foods, supplements and adjuncts are popular with consumers seeking a healthier lifestyle. These two patients exhibited no prior severe symptoms and may have been sensitized via birch pollen before first consumption of spirulina. As health supplements become more widespread, allergists and clinicians will have to consider their effect when diagnosing allergy, especially the correlation between birch pollen in this case.