Poison Oak

ExitCare ImagePoison oak is an inflammation of the skin (contact dermatitis). It is caused by contact with the allergens on the leaves of the oak (toxicodendron) plants. Depending on your sensitivity, the rash may consist simply of redness and itching, or it may also progress to blisters which may break open (rupture). These must be well cared for to prevent secondary germ (bacterial) infection as these infections can lead to scarring. The eyes may also get puffy. The puffiness is worst in the morning and gets better as the day progresses. Healing is best accomplished by keeping any open areas dry, clean, covered with a bandage, and covered with an antibacterial ointment if needed. Without secondary infection, this dermatitis usually heals without scarring within 2 to 3 weeks without treatment.


When you have been exposed to poison oak, it is very important to thoroughly wash with soap and water as soon as the exposure has been discovered. You have about one half hour to remove the plant resin before it will cause the rash. This cleaning will quickly destroy the oil or antigen on the skin (the antigen is what causes the rash). Wash aggressively under the fingernails as any plant resin still there will continue to spread the rash. Do not rub skin vigorously when washing affected area. Poison oak cannot spread if no oil from the plant remains on your body. Rash that has progressed to weeping sores (lesions) will not spread the rash unless you have not washed thoroughly. It is also important to clean any clothes you have been wearing as they may carry active allergens which will spread the rash, even several days later.

Avoidance of the plant in the future is the best measure. Poison oak plants can be recognized by the number of leaves. Generally, poison oak has three leaves with flowering branches on a single stem.

ExitCare ImageDiphenhydramine may be purchased over the counter and used as needed for itching. Do not drive with this medication if it makes you drowsy. Ask your caregiver about medication for children.


  • Open areas of the rash develop.

  • You notice redness extending beyond the area of the rash.

  • There is a pus like discharge.

  • There is increased pain.

  • Other signs of infection develop (such as fever).