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Dermatology Facts—Poison Oak: Prevention

Almost all parts of the body are vulnerable to the sticky sap. Since the sap must penetrate the skin to cause a reaction, parts of the body where the skin is thick are less vulnerable, such as the palms of the hands and soles of the feet. The amount of urushiol exposure may also affect the severity of the reaction.

What are the treatments and preventive measures?

Learn to recognize these plants so you can avoid contact with them. If you are going to be in a place where these plants grow, wear long pants, long sleeves, boots and gloves to reduce your risk of exposure.

Avoid direct contact with the plants to reduce the risk of a reaction. Urushiol may rub off the plants onto other things, such as pets or hiking gear, and can remain potent for months, especially in a dry environment.

Over-the-counter products such as IvyBlock help act as a barrier against urushiol and must be applied to the skin or clothes at least 15 minutes before contact with the plants. If you are exposed to the plants, products such as Zanfel and Tecnu are designed to wash away the urushiol from the skin and clothes and to lessen the effects of the exposure.

Your doctor may also prescribe a topical cortisone ointment or, if the reaction is severe, oral corticosteroids. Soothing agents such as calamine lotion, Sarna and Aveeno Oatmeal Bath may also help to relieve the itching and irritation.

Patients are strongly advised to cut their fingernails short. Scratching can lead to skin infection.

How long will this rash and discomfort last?

Depending on the amount of exposure to the urushiol and the severity of the reaction, most people experience symptoms for two days to three weeks. Treatment may significantly reduce the duration of symptoms.

Poison Oak Prevention and Treatments


Lotion that protects the skin against contraction of the rash. Apply to arms, hands and legs at least 15 minutes prior to risk of exposure to the plants. IvyBlock must be reapplied every four hours.


Waterless cleansing formula that decontaminates clothing and skin after exposure to the plants. When used within two to eight hours of exposure, Tecnu can remove any poison oak on the skin before the rash begins.


Topical treatment that removes the poison oak from the skin, thereby relieving the associated itch and rash. Most people experience relief within 30 minutes of application, and the rash may begin to subside within hours. Individuals who experience a systemic reaction to the poison oak, may need to reapply Zanfel every three to eight hours, or as new eruptions occur.


Moisturizing lotion that cools and helps control itching. Apply to affected areas two or three times daily, or as directed by your physician. Avoid contact with eyes. Do not apply under compresses or bandages.

Calamine lotion and Burrows solution

Dries the oozing and weeping and provides some relief from itching.

Aveeno Oatmeal Bath

The exact mode of action of colloidal oatmeal is unknown, but it is proven to relieve itching for up to several hours. It leaves a rather slippery, smooth texture to the skin, in contrast to the dry, rough texture after calamine applications.

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Redwood Family Dermatology
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Phone: 707-545-4537
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Redwood Family Dermatology
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Ukiah, CA 95482
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