What is a Poison Oak Rash?

A poison oak rash is an allergic skin reaction resulting from exposure to the oils secreted by the poison oak plant. Treatment for this condition may include self-care, the use of over-the-counter topical and oral medications, or injections and prescribed medications for severe reactions. Due to the risk for secondary infection, care should be taken when applying topical medications and scratching of the rash should be avoided.

Poison oak is a cousin to poison ivy and poison sumac and, like its cousins, direct contact with poison oak can result in a non-contagious form of contact dermatitis. Sensitivity to these toxic plants is very common and results from one’s exposure to the irritating, oily resin known as urushiol. The oil possesses the ability to remain on inanimate objects for long periods of time allowing for the continued risk of exposure and contamination. Items which are known to have been exposed to poison oak or its cousins should be cleaned thoroughly to prevent future rashes. The oil from these toxic plants may serve as a contaminant when burned and the smoke inhaled; therefore, the plants themselves or any items polluted with the oil should not be burned.

Individuals who come into contact with the poison oak plant may develop symptoms within eight hours of exposure. Those who are exposed to the plant for the first time may experience delayed symptom development with the rash appearing nearly a week following initial contact. Common symptoms include red, itchy, irritated skin and small bumps or hives developing on the affected area. Additional signs of exposure include the development of red streaks in the area that directly touched the plant and fluid-filled blisters that can rupture.

Subsequent exposures to the poison oak plant may manifest in a rash in as little as two days following contact with the urushiol resin. Rashes that develop from frequent exposure to poison oak will increase in severity with each instance. Severe reactions to poison oak are rare, but have been known to occur in individuals who have a heightened sensitivity to the plant. Individuals who experience a severe reaction to the plant may develop symptoms that include extensive blisters and a swelling of the face and neck. Those who develop a severe poison oak rash may remain symptomatic for up to six weeks.

A poison oak rash may be treated at home without the assistance of a health care provider. Products such as hydrocortisone cream and calamine lotion are available over the counter and work to effectively treat a poison oak rash. Itching associated with a poison oak rash may be treated with the application of an oatmeal bath or aluminum acetate. To prevent the spread of the rash and secondary infection, keep fingernails clean and avoid scratching the affected area directly.

Those who experience a severe reaction should seek prompt medical attention. A physician will generally ask a few questions to establish a time line to determine when the initial exposure occurred and when the rash developed. Individuals experiencing pronounced, severe symptoms may require prescription strength topical treatment used in combination with an oral corticosteroid to reduce inflammation. Steroidal injections may also be used to reduce swelling and inflammation.

There are a variety of approaches to preventing a poison oak rash. Individuals should educate themselves about the poison oak plant's appearance so that they may recognize and avoid it. Additional steps include applying a preventive cream to exposed skin and wearing appropriate clothing, such as socks or long pants and sleeves, when in areas where exposure to poison oak may be possible. Individuals who are severely allergic should make a conscious effort to avoid any contact with the poison oak plant.