Like many plants in our environment, cannabis contains components that can trigger allergic reactions in some individuals. An allergy to cannabis is a recognized immune system response, meaning the body mistakenly identifies certain substances in the plant as harmful. These reactions are genuine and can present in a variety of ways. Understanding the potential for such sensitivities is important for anyone exposed to the plant.
Recognizing Allergic Reactions
Allergic reactions to cannabis can manifest in diverse ways, often depending on the method of exposure. Skin contact with the plant, including hemp varieties, may lead to localized symptoms such as hives, itching, redness, or a dry, scaly rash. These reactions can appear immediately after touching the plant or its products.
Inhaling cannabis allergens, whether through airborne pollen from male plants, smoke, or dust from the plant material, frequently results in respiratory symptoms. These can include a dry cough, nasal congestion, sneezing, and an itchy or runny nose, similar to seasonal allergies. Individuals may also experience itchy, red, or watery eyes, along with wheezing and shortness of breath.
Systemic reactions, though less common, can also occur, especially from ingesting cannabis products. These may involve nausea, vomiting, or diarrhea. The most severe reaction is anaphylaxis, a life-threatening condition characterized by sudden hives, swelling of the face or mouth, rapid and shallow breathing, a fast heart rate, and a sudden drop in blood pressure. Anaphylaxis requires immediate medical attention.
Understanding Allergenic Components
Allergic reactions to cannabis are primarily driven by specific proteins found within the plant. The most studied of these are non-specific lipid transfer proteins (nsLTPs), particularly one identified as Can s 3. Other allergenic proteins include profilins and oxygen-evolving enhancer protein 2 (Can s 4). These proteins can be present in various parts of the plant, including pollen, leaves, buds, and seeds.
Cannabis pollen, released by male plants, is a significant airborne allergen that can trigger respiratory symptoms. In addition to proteins, certain aromatic compounds called terpenes, such as linalool, limonene, pinene, and caryophyllene, can also contribute to allergic responses. These terpenes have been linked to contact dermatitis and respiratory irritation. It is important to distinguish a true cannabis allergy from reactions caused by contaminants like mold or dust mites, which can thrive on improperly stored cannabis but are not inherent to the plant itself.
Confirming a Cannabis Allergy
Diagnosing a cannabis allergy requires evaluation by a healthcare professional, typically an allergist. The process usually begins with a detailed medical history and a physical examination to understand the patient’s symptoms and exposure.
Allergists may perform skin prick tests, where a small amount of diluted cannabis allergen extract is applied to the skin. If a person is allergic, a red bump or wheal, accompanied by itching, may develop within 15 to 20 minutes. While standardized tests for cannabis are not universally available, allergists can prepare extracts for this purpose. Blood tests, such as specific IgE tests (e.g., ImmunoCAP, ELISA, RAST), can also detect antibodies produced by the immune system in response to cannabis allergens.
Steps for Managing the Allergy
The most effective strategy for managing a cannabis allergy is avoidance of exposure. This includes minimizing contact with the plant itself, avoiding inhalation of smoke or pollen, and refraining from consuming cannabis-infused products.
For mild to moderate symptoms that occur despite avoidance efforts, over-the-counter medications can provide relief. Antihistamines may help reduce itching, sneezing, and runny nose, while nasal decongestants and intranasal corticosteroids can alleviate nasal symptoms. Topical steroid creams can be applied to manage skin reactions. For individuals at risk of severe reactions, such as anaphylaxis, an allergist may prescribe an epinephrine auto-injector for emergency use. These symptomatic treatments manage the allergic response but do not cure the underlying allergy.
Related Allergic Sensitivities
Individuals with a cannabis allergy may also experience reactions to other substances due to a phenomenon known as cross-reactivity. This occurs when proteins in cannabis share structural similarities with proteins found in other plants or foods, causing the immune system to react to both. A significant contributor to this is the non-specific lipid transfer protein (nsLTP), Can s 3, which is highly similar to nsLTPs in various fruits and vegetables.
Common examples of cross-reactive foods include:
Peaches
Tomatoes
Almonds
Apples
Bananas
Cherries
Hazelnuts
This cross-reactivity can lead to “oral allergy syndrome,” where consuming raw fruits or vegetables causes itching or tingling in the mouth and throat. Other plants like hops and mulberry may also exhibit cross-reactivity with cannabis.