The Poison Control Center

Summertime Skin Irritants

Poison Ivy, Poison Oak and Poison Sumac

Poison Ivy, Poison Oak and Poison Sumac

Although poison ivy, poison oak and poison sumac are often thought of as summertime hazards, these plants are also commonly found throughout the fall season.

Poison ivy, poison oak and poison sumac are common causes of seasonal, allergic contact dermatitis (rash). It has been estimated that up to 70 percent of the U.S. population has an allergic reaction after an exposure to these plants. The reaction may range from mild, localized redness and itching to severe blister formation and swelling over the entire body. The severity of the symptoms depends on the patient's degree of sensitivity, the amount of contact with the offending material and the areas of skin involved.

The offending material in all species of poison ivy, poison oak and poison sumac is an oily resin known as urushiol. This oily resin is found in the leaves, stems, roots and berries of all of these plants. When this resin comes in contact with the skin or fingernails, it clings there and becomes tightly bound within minutes.

Contrary to popular belief, the fluid in blisters caused by poison ivy, oak and sumac does not spread the rash. It is the oily plant resin that is the culprit. The offending resin can remain active for long periods of time on contaminated clothing, shoes sports or hunting equipment, camping gear, garden and yard tools and even the family pet.

First aid




A jellyfish's tentacles are loaded with small bee-like stingers that contain a toxin used to stun small water prey. This is why within four to 24 hours after a human is exposed to the stinger of a jellyfish, the affected skin can become painful, red and swollen and an itchy rash can appear.

With severe stings — when a lot of venom is injected into the skin or when a person is extremely allergic to the venom — weakness, dizziness, nausea, headache, muscle aches and spasms, and difficulty breathing can result. If severe symptoms occur, the victim should be seen by a physician or emergency room staff. If symptoms are mild, the following first aid advice may help:


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