Systemic poison ivy is an extreme allergic reaction to the urushiol oil found in a poison ivy plant. Unlike a typical reaction to poison ivy, which causes a localized rash to appear on the skin where contact took place, a systemic reaction is one that is not isolated to one area. These rashes may spread all over the body, including to areas that had no direct contact with the plant. This condition can be life-threatening, but there are treatments available.
People can develop systemic poison ivy by coming into contact with something that has urushiol on it. This can be anything that's touched a poison ivy, oak, or sumac plant, like clothing or pets. Mowing over these plants can cause little pieces of them to become airborne, which can spread the urushiol even further. Even dead plants or items that touched poison ivy a long time ago should be avoided, as the oil can remain active on any surface for years. Once the urushiol goes through the top layer of the skin, it bonds with a type of white blood cell called Langerhan's cells, and from there can spread throughout the body.
Along with direct contact with the plant, a systemic reaction to poison ivy may be also be caused by smoke inhalation. If a tree stump or other type of plant material laden with poison ivy is burned, the smoke produced is extremely dangerous to humans. Once urushiol enters the lungs via smoke, it can cross into the bloodstream, causing blisters and rashes to cover the entire body. Even the mouth and throat are often affected in especially severe cases of systemic poison ivy.
Initially, someone with systemic poison ivy will notice scattered itchy rashes on the skin, which appear a few days after exposure to urushiol. If rashes are still appearing in new places four days after the first patch appeared, then a person most likely is having a systemic reaction. Other symptoms include headaches, nausea, swollen lymph nodes, swollen joints, and a fever. Patients who inhaled urushiol-laden smoke may also experience difficulty breathing.
During the final stage of the condition, the rashes will turn into blisters, which may ooze for several weeks. Though the blisters themselves do not contain urushiol, and are not contagious, they still shouldn't be popped, as this can lead to an infection. If the blisters are on delicate places like eyes or genitals, or they cover between 15 to 30% of the body, a person should seek medical attention.
Any person who suspects systemic poison ivy reaction should seek medical attention. A doctor will most likely prescribe steroid injections, starting the patient at a fairly high dose which gradually tapers off over the course of a few weeks. Antihistamines and over-the-counter medications, such as diphenhydramine, may also be taken to ease breathing and relieve discomfort. In severe cases, hospitalization may be required.
Doctors typically recommend that extra steps be taken in treating systemic poison ivy cases involving children, as they are frequently unable to resist scratching the lesions. Loose, lightweight cotton clothing is recommended to cover the rash and restrict the child's access while allowing air to reach the skin. Cold or lukewarm water can be used to make oatmeal baths to reduce itching as well, but hot water should be avoided, as this can actually increase itching. To reduce the possibility of infection if the child does scratch, his or her fingernails should be trimmed short and his or her hands should be washed frequently.