Whether it's sniffling, watery eyes, itching, or asthma, many of us are all too familiar with symptoms of allergies.
According to the Asthma and Allergy Foundation of America, allergies are the sixth leading cause of chronic illness in the US. There were 19.2 million adults diagnosed with hay fever in 2021, according to the Centers for Disease Control and Prevention (CDC). It is estimated that 32 million Americans live with food allergies; more than 170 foods may lead to an allergic reaction.
Considering the increasing awareness and use of cannabidiol (CBD) and the existing potential for pollen and food allergies, allergy sufferers may wonder whether they are at risk for an allergic reaction to CBD or whether it can provide treatment or relief for other types of allergic reactions.
Though there's not much in the way of allergy research specifically for CBD at this point, the cannabis plant itself has been linked to allergic reactions.
“Marijuana is a plant and produces pollen and one can become allergic to the pollen and the plant, especially if one has pre-existing allergic tendencies,” said Dr. William S. Silvers, clinical professor of medicine in allergy and immunology at the University of Colorado School of Medicine.
That being said, only male marijuana plants produce pollen, and they are exceedingly rare in cannabis and hemp production because they produce less oil and CBD than female plants. Therefore, a consumer's exposure to pollen would be extremely rare.
CBD overview
CBD is the second-most-prominent cannabinoid derived from the cannabis plant, after the intoxicating cannabinoid tetrahydrocannabinol (THC). CBD, extracted from marijuana or industrial hemp, has gained popularity for its potential benefits for a number of conditions, including inflammation, arthritic pain, depression, seizures, and anxiety.
Though research is still limited in regards to many supposed benefits, in 2018 the FDA approved Epidiolex, an oral CBD solution, to treat seizures associated with two severe types of epilepsy, Dravet syndrome and Lennox-Gastaut syndrome.
Allergies in the body
A properly functioning immune system works to protect the body from pathogens such as bacteria, viruses, and fungi, and attack these unwanted microorganisms in order to help prevent disease. In the case of allergies, the immune system triggers a reaction to plant pollen and other harmless substances in the environment. The result, depending on the type of allergy, can be a variety of symptoms, including itchy eyes, runny nose, asthma, hives, skin itching, or more severe reactions such as anaphylaxis, which can be life-threatening.
Allergic reactions to CBD
Humans commonly experience allergic reactions to many kinds of plant pollen. However, only male cannabis plants produce pollen, whereas female plants are more widely used for oil and cannabinoid production. Large-scale industrial hemp fields may include a variety of mature males (pollen) as well as fertilized females (oil and seeds). The impact of hemp pollen on everyday consumers, as well as the communities that work and live near these production facilities, has not been studied.
People can also develop allergies to some of the terpenes found in cannabis. For instance, researchers from the Duke University School of Medicine found that about 20% of the 100 people they tested had an allergic skin reaction to linalool, whereas 8% had reactions to limonene. These kinds of contact allergies may not be common in the general population, but anyone with these allergies working in the cannabis production industry could have health consequences.
Dr. Gordon Sussman, an allergist in Canada and professor at the University of Toronto, said there is very little published research on CBD allergies. “It's an unknown area at this point,” he said. “But we know that cannabis sativa is an allergen and we know that it's a common allergen.”
Humans commonly experience allergic reactions to many kinds of plant pollen. Only male cannabis plants produce pollen. Most cannabis products, including CBD oil, are made using female plants.
He said that cannabis allergies, like other forms of allergies, can worsen as exposure to the allergen continues. Most people with cannabis allergies suffer from a runny and stuffy nose (rhinitis), eye irritation (conjunctivitis), and sometimes wheezing, Sussman explained. But there have been cases of more severe reactions such as anaphylaxis, which have primarily resulted from ingestion of hemp seeds.
According to a letter entitled “Marijuana and stoned fruit,” written by doctors from the University of California, San Diego, and published in the Annals of Allergy, Asthma, and Immunology in 2018, a 24-year-old man who smoked marijuana daily visited their allergy clinic two weeks following an anaphylactic reaction after eating yogurt with hemp seeds.
“This was his first known ingestion of hemp seeds. Immediately after consumption, he developed oral pruritus [itching] that progressed to shortness of breath, facial swelling, and pre-syncope [sensation prior to fainting],” the letter stated.
Those with food allergies may also be susceptible to cross-reactivity.
“You can have a cross-reaction with certain foods that share certain antigens, certain components, with the cannabis plant itself,” Silvers said.
Such foods may include tomatoes and fruits containing pits, such as peaches, he said. It's a similar cross-reactivity to what is seen in people with ragweed allergies who might experience symptoms such as itchy mouth if they eat fruit in the melon family, he added.
“The same thing goes with cannabis and tomatoes and peaches and almonds and a number of other foods … eggplant, grapefruit, apples,” Silvers said.
He also noted that the type of allergic reaction depends on the type of exposure. In addition to cannabis pollen allergies and food-based allergies, skin allergies are also a possibility. “Touching the plant can very easily lead to dermatitis, itching, and skin reactions,” he said.
Can CBD help with allergies?
While there isn't much research supporting the idea that CBD can help the discomfort associated with common allergy symptoms, there is some research related to its general effects on inflammation, which is part of the body's allergic reaction process. A study published in the Journal of Pharmacology and Experimental Therapeutics in 2018 showed that CBD was effective in reducing inflammation associated with allergic contact dermatitis in a lab model using human cells.
According to Silvers, there is no clinical evidence that CBD products can treat allergies. While there is experimental laboratory research suggesting anti-inflammatory effects exist, there's no clinical patient substantiation.
Major contributions from Dr. Adie Rae.