Basics

• Poison oak is found all over the United States. On the Pacific Coast, the plant grows at any sea level and is characterized by three- to five-veined shiny leaves. On the Atlantic side, each leaf contains three leaflets that are hairy or fuzzy. Poison oak is dangerous because of its release of toxicodendrol, which contains the poisonous element urushiol. This substance does not dissolve in water, meaning the poison is notoriously hard to wash off. In addition, it often spreads by remaining under the fingernails, so wash thoroughly and change clothes if you suspect an infection.
  
  

Symptoms

• The severity of the symptoms caused by poison oak infection differ depending on factors such as area of infection, sensitivity of skin and amount of exposure to the poison. The worst areas to get a poison oak infection are the eyes, genitals or lips, because they are the most sensitive. Usually the symptoms manifest within a day or two of infection, though it can be in only 30 minutes. The symptoms are redness, severe itching, swelling and blistering, and they are at their worst generally five days after infection. Symptoms tend to disappear a week to a week and a half after an infection.
  
  

Treatment

• If the poison causes a swelling of the face or throat or is spreading rapidly, a doctor should immediately be consulted. Otherwise, the best treatment is protecting the affected areas to avoid other infections and relieving the itching. Aloe vera can protect against infection and calamine lotion can relieve the itch, as can holding an infected area under hot water to overload the nerve cells and shut them down for a few hours. The best methods for prevention of poison oak infection are wearing protective clothing, keeping an eye out and avoiding the distinctive three leaves, and washing thoroughly if contact is made with the plant.