RATIONALE: Hemp, (C. sativa) is an annual herbaceous weed of the family Cannabinaceae that produces flowers, leaves and seeds. Hemp seeds are added to cereals, granola, and pressed to produce oil. Leaves of C. sativa are known for their psychoactive effects due to tetrahydrocannabinol (THC). Hemp seed contains negligible THC content. There are very few reports on hemp seed allergy. We aim to present the clinical features and the diagnostic approach in 5 patients with anaphylaxis to hemp seed.
METHODS: Epicutaneous skin prick testing (SPT) was performed to hemp seed in all patients as well as a healthy control. A positive test was defined as 3 mm greater than the negative saline control.
RESULTS: There were 4(80%) males and 1(20%) female, ranging in age from 13-40 years (mean age 25 years). 80% were atopic. All patients presented to an emergency room with anaphylaxis shortly after ingestion of hempseed. 60% of patients received isolated antihistamine, 20% received isolated epinephrine, and 20% received both treatments. All were prescribed an epinephrine autoinjector. All had positive SPTs to fresh hemp seed, with an average wheal size of 10.3mm (3/5 patients).
CONCLUSIONS: We present one of the first case series of pediatric and adult patients with anaphylaxis to hemp seed ingestion. This allergy appears to manifest later in life as anaphylaxis. Allergists should be aware of the potential allergenicity of hemp seed, especially with the increasing commercial availability of foods containing hemp seed and its derivatives.