On Friday March 2, 2018 at the World Allergy Congress it was revealed that Cannabis (Marijuana) is a new allergen, reported to occur in about 10% of people exposed, 33% of people who have used and 7% of regular users.  We expect this to increase as usage increases.  Symptoms include cutaneous (hives, contact swellings), respiratory (nasal congestion, sneezing, wheezing), and potentially life-threatening anaphylactic reactions as well as anxiety or cramps.  Latex, tobacco, wine and beer may cross react with cannabis.  There also was reported from Europe that there is also an oral-cannabis reaction which may include reactions to walnut, peach, apple, tomato, banana, hazelnut, peanut, wheat, tangerine and orange thought to be mediated by lipid transfer factor. Chronic users may develop hyperemesis syndrome (persistent vomiting).