As cannabis use becomes legal in more states, many people are seeking it out for medical use. Medical cannabis can be used to treat  symptoms of pain, insomnia and anxiety.

Researchers say cannabis use is poorly studied in allergy and asthma patients. Last year, Allergy & Asthma Network partnered with Canna Research Foundation to conduct a national survey of adults with asthma and cannabis (marijuana) use.

The Allergy & Asthma Network Pain, Exercise and Cannabis Experience (PEACE) survey results were recently published in the Annals of Allergy, Asthma & Immunology.

The survey involved 489 adults recruited by Allergy & Asthma Network. Researchers learned that 18% used cannabis. The majority of participants were female (72.4%) and Caucasian (71.6%).

Is it safe for people with asthma to smoke cannabis (marijuana)?

Many people with asthma are smoking or vaping cannabis. This could be harmful to their lungs and airways, especially in adolescents.

In the PEACE survey, 53.4% of cannabis users with asthma smoked it, while 35.2% vaped cannabis. Further, about half of the cannabis smokers with asthma reported uncontrolled asthma symptoms.

“It surprised me that over half of the cannabis users in the study who have asthma were smoking it,” says Joanna Zeiger, PhD, principal investigator of the PEACE survey.

It’s not recommended that people with asthma smoke or vape cannabis. Smoking or vaping cannabis can cause increased cough, wheezing and shortness of breath. It can increase risk of an asthma attack or asthma flare. In the PEACE survey, nearly one-third of those who smoked cannabis reported cough.

Is there a safe way to use cannabis if you have asthma? Are there benefits?

There may be potential cannabis benefits for asthma when taking it in other ways than smoking or vaping. Alternative ways to use cannabis include:

  • cannabis edibles
  • cannabis tincture/oil
  • cannabis topical products.

These routes of administration may be safer since they do not impact the lungs the same way inhaled routes (smoking or vaping) do.

In addition, smoking cannabis or being exposed to secondhand cannabis smoke could cause an allergic reaction.

“For some people with asthma, cannabis acts as an immediate bronchodilator. A bronchodilator relaxes the airways which can help breathing.  But that doesn’t make cannabis a long-term solution for asthma control,” Zeiger says. “Patients need to speak with their doctors about their cannabis use. They should work together with their doctor to decide on the route of administration that is safest for them.”

In the PEACE survey, participants also cited their purpose for using cannabis. These included:

  • medical reasons (26.1%)
  • recreational use (34.1%)
  • both medical and recreational use (39.8%).

Survey participants reported improved sleep, less pain and decreased anxiety after using cannabis. But survey participants also reported increased symptoms after using cannabis:

  • coughing (19.3%)
  • wheeze (5.7%)
  • shortness of breath (6.8%).

It appears that many asthma and allergy patients are using cannabis for a variety of reasons that may have nothing to do with their asthma, Zeiger says.

Can you be allergic to cannabis (marijuana)?

Yes, people can be allergic to marijuana.  People can develop an allergy to cannabis even if they are not cannabis users.  About 2.5% of participants in the PEACE survey who were NOT current cannabis users reported a cannabis allergy. As more states legalize cannabis, doctors should expect to see more people experience allergic reactions to cannabis. This can occur due to  occupational exposures. These reactions may be specific to a strain of cannabis.

It’s likely cannabis allergies have been around for years. Cannabis allergy may have gone  unreported due to its illegal status. In addition, there is no current way to test for cannabis allergy.

Cannabis pollen grains typically emerge in late summer or early autumn and they can become airborne. This can cause an allergic reaction in some people.

What are cannabis allergy symptoms?

Cannabis allergy symptoms include:

  • nasal congestion
  • eye inflammation
  • coughing
  • wheezing

Skin contact with marijuana – including the hemp version sometimes used in clothing – may cause eczema or hives. Severe reactions, including anaphylaxis, have been reported.

Should people who use or smoke cannabis talk with their doctor about it?

The researchers conducting the PEACE survey also sought to determine whether doctors and patients openly discussed cannabis use during visits.

In the PEACE survey, 37.5% of patients wanted to discuss cannabis use with their doctor. About 41% of doctors asked their patients either verbally or on an intake form about cannabis use.

Dr. Zeiger says doctors and patients need to be better educated on cannabis use and its potential health benefits and risks. More research is needed to learn more about cannabis use and its impact on asthma, allergies, eczema and urticaria.

“Patients should not be afraid to discuss cannabis with their doctors,” Dr. Zeiger says. “Patients want to be sure there won’t be any adverse effects of using cannabis with any other medications. And doctors need to know the benefits and adverse effects.”

How can doctors best help allergy and asthma patients who use cannabis?

In an American College of Allergy, Asthma & Immunology press release, board-certified allergist William Silvers, MD, said:  “In order to more completely manage their allergy and asthma patients, allergists should increase their knowledge about cannabis. These include:

  • types of cannabinoid
  • route of use
  • reasons for us
  • side effects.

Efforts should be made to reduce smoking of cannabis and recommend other safe routes such as edibles and tinctures.”