Hemp seeds, derived from the Cannabis sativa plant, have become increasingly popular in foods like cereals, smoothies, and baked goods. A person can develop an allergy to hemp seeds, although these instances are relatively rare compared to common food allergies like peanuts or tree nuts. The immune system can mistakenly identify the seed’s proteins as a threat, triggering a range of allergic responses upon ingestion.
Signs of an Allergic Reaction
Reactions to hemp seeds can range from localized discomfort to severe systemic responses. Mild symptoms often involve the skin and the digestive tract, typically appearing shortly after consumption. These symptoms include hives, generalized itching, or swelling, particularly affecting the lips, tongue, or eyelids. Individuals may also experience Oral Allergy Syndrome, characterized by itching or tingling inside the mouth and throat. Gastrointestinal distress is a common initial sign, presenting as nausea, vomiting, abdominal pain, or diarrhea.
In a smaller number of cases, ingestion of hemp seeds can trigger anaphylaxis. This dangerous condition involves multiple body systems and may include difficulty breathing, wheezing, a sudden drop in blood pressure, or a feeling of impending doom. Anaphylaxis constitutes a medical emergency and requires immediate intervention with an epinephrine auto-injector and professional medical care. Rapid identification of symptoms and prompt action are paramount when a severe reaction is suspected.
Specific Allergens and Cross-Reactivity
The allergic reaction is an immune response to specific proteins found within the hemp seed. The two main storage proteins are edestin (an 11S globulin) and albumin (a 2S albumin), which account for the majority of the seed’s protein content. These proteins, along with vicilins (7S proteins), are the primary molecular structures the immune system tags as allergenic.
Panallergens have also been identified, including profilins (Can s 2) and Lipid Transfer Proteins (LTPs or Can s 3). These proteins are found across multiple plant species and often cause cross-reactivity.
A connection exists between hemp seed allergy and sensitization to Cannabis sativa pollen. Individuals sensitized to cannabis pollen may experience an allergic reaction upon ingesting the seeds due to cross-reactivity. Furthermore, hemp seed proteins share structural similarities with proteins in other common food allergens. This means people with known allergies to certain nuts or seeds, such as hazelnut or peanut, may be at a higher risk of reacting to hemp seeds.
Testing and Management
A suspected hemp seed allergy is confirmed through medical history and diagnostic tests performed by an allergist. The most common initial procedure is a skin prick test (SPT), where a small amount of hemp seed extract is applied to the skin to observe for a localized reaction. A positive SPT, indicated by a raised wheal, suggests the presence of Immunoglobulin E (IgE) antibodies specific to hemp proteins. Following the SPT, an allergist may order a blood test to measure the level of hemp-specific IgE antibodies. While these tests indicate sensitization, they do not definitively prove a clinical allergy; therefore, an oral food challenge may be considered for confirmation under strict medical supervision.
The primary and most effective management strategy for a confirmed hemp seed allergy is strict avoidance of the seeds and any products containing them. For those with a history of mild reactions, over-the-counter or prescription antihistamines may be used to manage symptoms like hives or itching. Patients who have experienced or are at risk for anaphylaxis are usually prescribed an epinephrine auto-injector and trained on its immediate use in an emergency.