Background: Sunflower seed is one of the most common edible seeds. Its consumption is growing. Cases of sunflower seed allergy have been reported since the 1970s. However, there are few data on the prevalence and clinical manifestations of sunflower seed allergy.
Objective: To improve our understanding of sunflower seed allergy.
Methods: We evaluated the clinical and immunological features of patients with sunflower seed allergy diagnosed in the allergy department of a tertiary hospital in Madrid over a 5-year period.
Results: Forty-seven patients reported adverse reactions after ingestion of sunflower seed and were sensitized specifically to sunflower seed, as determined by skin prick test (median, 8 mm) or specific IgE (median, 1.10 kUA/L). Most reactions were adult-onset and were preceded by a history of atopy and other food allergies, predominantly to peach, peanut, and nuts. The clinical presentation of sunflower seed allergy ranged from mild to severe, with many patients experiencing severe reactions, in which epinephrine was underused. Repeated exposures to sunflower seed in the same patient showed severity of symptoms to vary. Levels of sunflower seed IgE were strongly correlated with levels of IgE to nonspecific lipid transfer proteins, while the severity of the reactions did not differ significantly according to sensitization to the proteins.
Conclusion: Our findings reveal variability in the clinical presentations of sunflower seed allergy on repeated exposures and underuse of epinephrine in anaphylaxis. We highlight the importance of strict avoidance of sunflower seed and accurate prescription and administration of epinephrine in allergic patients.

Key words: Sunflower seed, Food hypersensitivity, Severity, Skin prick test, Specific IgE