The majority of allergic reactions consist of itchy, watery eyes and a runny nose. Such symptoms are typical of allergies to pollens, animals, dust mites, and so on. Other reactions, such as reactions to poison ivy or to a particular detergent, result in itchy rashes and blisters. These reactions are called contact dermatitis because you must rub against or come in contact with the substance before a reaction occurs. This resin is extremely irritating and may be a potent sensitizer, since further contact with the resin may produce increasingly severe reactions.
Sensitivity tends to be increased with repeated exposure.
Contact with anything that has touched the plant can spread the resin, i.e. clothing, pets, tools. Smoke from burning the plants vaporizes the resin which can cause very severe reactions. Most of the time a rash develops in 12 to 72 hours after exposure. The rash usually appears as itchy, moist, blistered lesions that weep a clear to yellowish liquid. Generally, the rash requires 2-3 weeks to heal.