Marijuana Might Help Cure Allergic Contact Dermatitis (a.k.a. Poison Ivy)

Kevin Berman, MD, PhD Health Guide August 21, 2007
  • As most of us know, the medicinal use of marijuana is very controversial from a political and moral perspective. This is because marijuana is a drug that has both physiological and psychological effects that have convinced lawmakers that it should be illegal to possess. Today, I'd like to talk about marijuana and its potential, legal use for allergic contact dermatitis.

     

    Allergic contact dermatitis is a very common condition that results from physical contact with something that causes an allergic reaction. The most notorious example of allergic contact dermatitis is poison ivy, in which there is a delayed reaction to the contact with poison ivy that leaves a person very itchy about 2 days after being out in the woods or in the garden. Another very common example is a person who is allergic to nickel and breaks out in an itchy rash from earrings, a watch, or the metal buttons and snaps on pants. Allergic contact dermatitis can even be work related. An example would be a construction worker who is allergic to the cement he is working with all day and is forced to change jobs. While all the mechanisms leading to the rash are not clear, we do know that the body has an exaggerated reaction which causes the skin to become hyperactive. In other words, the immune system is overactive in the skin and a rash ensues.

     

    Marijuana is derived from the hemp plant, which is also used to make clothes and rope, in addition to its psychoactive and medicinal purposes. The active elements of marijuana are the cannibinoids, which are responsible for its effect on the human mind and body. In recent years, scientists have discovered that these cannibinoids bind certain receptors in the body and brain, and that our bodies naturally make chemicals that are very similar to the cannibinoids from the marijuana plant.

     

    The two main receptors from the marijuana plant are termed CB1 and CB2, and the naturally occurring cannabis like chemicals in the human body are called anandamide (found in the brain) and 2-AG (from the intestine). Their effects are numerous, and as a result, these receptors have theoretical uses in cases of multiple sclerosis, spinal cord injury, pain, inflammatory disorders, glaucoma, bronchial asthma, vasodilatation that accompanies advanced cirrhosis, and cancer. The CB-1 and CB-2 receptors, for example, have been linked to appetite, and they can potentially be used to increase the appetite of emaciated cancer patients. CB-1 and CB-2 have also been linked to pain alleviation, and their use can be easily justified for cancer patients or people with a painful condition of the pancreas called pancreatitis. Several years ago, scientists discovered their potential use for Alzheimer's Disease prevention.

     

    Until recently, dermatologists would be hard-pressed to find a reason to suggest that a patient use cannabis for his or her skin. However, several months ago, scientists tested a mouse with hypersensitive skin to show the potential use of marijuana in allergic contact dermatitis. Mice are a useful investigative tool in science because their genes can be manipulated, and at the gene/cell level people and mice are remarkably similar. For this reason, experiments are performed on mice and their conclusions are usually assumed safe for testing on humans.

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    Scientists found that mice lacking the CB-1 and CB-2 receptors had exacerbated inflammatory reactions in the skin and extreme skin hypersensitivity. They also found that mice with abnormally increased levels of anandamide (the naturally occurring cannabis like substance) had decreased inflammation of the skin. They also showed that chemicals that would block the effects of marijuana on the CB-1 and CB-2 receptors would result in more skin sensitivity. From these experiments with mice, it appears that activating the CB-1 and CB-2 receptors would reduce the symptoms of rashes similar to poison ivy. As a result, scientists have an incentive to design a molecule similar to marijuana that may be a safer alternative to using marijuana in its more traditional forms.

     

    I hope I have shed a little light on the use of marijuana for medical purposes, more specifically for allergic contact dermatitis. You should certainly not attempt to treat poison ivy with marijuana and I am not promoting the use of marijuana unless you are under medical supervision. As of now, if you have poison ivy, consult your dermatologist and use the prescribed oral and topical steroids and antihistamines.