Many people think a poison plant rash can be spread from one part of the body to another or from person to person. In general, this is not true. You can spread the rash only if you have urushiol on your hands. Also, it can take longer for the rash to appear on certain areas of the body, especially areas such as the soles of the feet where the skin is thicker. This might give the appearance that the rash has spread from one part of the body to another. You also can be re-exposed to the urushiol by touching gardening tools, sports equipment, or other items that were not cleaned after being in contact with the plants. Scratching or touching the rash and fluid from blisters will not cause the rash to spread because urushiol is not present in the blister fluid.
The oily resin called urushiol is the specific component found in the sap of poison oak that produces the allergic reaction. Rashes will usually develop 12 to 48 hours after the skin was able to come into contact with the plant. The irritant can be spread to other surface or other people through any means of direct contact with items or skin that has touched the poison oak sap. Indirectly causing the poison oak rash can result if a person unwittingly touches any clothing or belongings that have been exposed to poison oak. The rash can also develop after stroking the fur of a pet which had come into contact with the plant.
Treating poison oak has a bearing on how long the rash and itching go on. The aim is to control the symptoms: Reduce the urge to scratch the itch and keep the redness and swelling from becoming a problem until they have time to heal. The best nonprescription medications include corticosteroid creams (like hydrocortisone), aloe vera gel, calamine lotion or anything with menthol as an ingredient. They soothe the skin and (in the case of corticosteroids) help address the allergy directly. In some cases, oral antihistamines can be helpful as well. In the worst cases, scratching can cause a bacterial infection, which requires antibiotics and a doctor's care to properly treat. You may also wish to get prescription-strength corticosteroids if your doctor feels it is warranted. If the rash isn't so bad, you can use home remedies such as cold compresses or colloidal oatmeal baths to help reduce the symptoms.