This condition can be life-threatening and occurs within seconds or minutes of exposure to an allergen.

Less commonly, marijuana can cause a severe allergic reaction called anaphylaxis. To stop symptoms from getting worse, a person who notices these effects should immediately stop touching or smoking the drug. Symptoms of marijuana allergies can come on immediately after exposure to the plant, although, in other cases, they may not begin for an hour or more. Handling the drug may also cause contact dermatitis, a skin reaction that can have the following symptoms: Common symptoms of a marijuana allergy, many of which are similar to seasonal allergy symptoms, include: