The good news about poison oak is that about 15 percent of people are immune to its effects. The bad news is that, like me, you’re probably in the other group.
Over the years, I’ve treated several thousands of cases of poison oak and the one thing I’ve learned is to respect it. I’m sure poison oak was created to keep mankind humble.
Poison oak is an allergic reaction caused by contact with urushiol, which is the oily sap of the poison oak plant. It is the same substance found in other poison plants, like poison ivy and poison sumac. Interestingly, it is also found in mango rinds and the fruit (not the nut) of the cashew tree.
Urishiol is a colorless oil found in all parts of the plant, including leaves, stems and roots. It is so potent that it has been reported that an amount of oil that could fit on the head of a pin could cause rashes to several hundred people.
One can contact poison oak oil in the following ways:
1. Direct contact: touching the sap of the plant.
2. Indirect contact: touching something on which the oil is present, such as the fur of a pet, garden tools, sporting equipment and especially contaminated clothing. The poison oak oil can remain active on these objects for many months. (Continue reading for ways to remove the oil.)
3. Airborne contact: breathing the smoke from burning poison oak. There have been reports of this in literature, but I have never witnessed it with any of my patients.
When urushiol contacts the skin, it penetrates within minutes. A reaction will appear within 12 to 72 hours in those of us who are allergic to it.
A common misperception is the idea that a good shower at the end of the workday will be sufficient to prevent a poison oak rash. I repeat, you have only a few minutes to wash it off of your skin.
The best way to wash it off is somewhat open to debate. Some medical experts would argue that water alone is sufficient to wash the oil off the skin. The water can be any temperature, as there is no proof that heat opens the pores of the skin to allow for more absorption of the oil. I have personally experienced that soap and water does the job, although some would argue that soap might spread the oil. I have never seen nor had this happen. I figure that if soap is universally recommended to use in the washing machine to remove the oil from the contaminated clothes, then it should also work to wash it off your skin.
Whichever routine you wish to use, we can agree that a copious amount of water is necessary. Some authorities maintain that rubbing alcohol should be used to decontaminate the urushiol oil. I could find no controlled studies to verify this.
Remember to also wash your shoes, as one common source of continued recontamination comes from touching shoes and shoelaces after they have had contact with poison oak. Also, be aware that when you take your clothes off at the end of the day to throw them in the washing machine, your hands can become recontaminated and you can thereby spread the oil further on your body.
Once you have bathed and removed the oil from the skin, you can no longer spread poison oak to anybody or anything. But sometimes, no matter what you do, you’re going to end up with a rash. That’s the mystery of poison oak.
Poison oak rash never becomes systemic. It is medically called a “contact dermatitis,” and the only place where a rash can develop is where the urushiol oil has contacted the skin. Poison oak rash can affect almost any part of the body. The rash does not spread by touching it, although it may seem to when it breaks out on new areas over a number of days. This may happen because the oil absorbs more slowly on thicker skin, such as the forearms, legs or trunk.
Can poison oak rash be prevented before contact with the oil? Some allergy pills or shots have been used with limited success, but in general, they are no longer used, because of potentially serious side effects.
I have pulled out poison oak plants while clothed from head to toe and wearing thick, heavy-duty rubber gloves washed frequently in a bucket of soapy water I keep at my side. I very carefully try not to allow my clothing to touch the plant. When my task is done, I run into the house (with my shoes left at the door), throw my clothes in the washing machine and jump into the shower. This has worked fairly well for me.
Once the rash begins, you have several choices to ease the discomfort. A lotion called Technu may help some people, but not others. If the rash forms blisters that begin to weep, applying over-the-counter Domeboro as a wet compress is helpful in drying the rash. Hydrocortisone cream is basically ineffective.
Mild cases can usually be tolerated without treatment and will disappear within a week or two. Depending on the severity, a person can be treated by a health care provider to heal the rash with prescription steroid creams, or if needed, systemic cortisone can be taken as pills for about two weeks or by a single steroid injection, especially if the rash involves the face. Let your provider know which form has worked best for you in the past, or if it’s your first visit for this rash, let your provider determine which method is best. In my experience, the benefit of either cortisone treatment far outweighs any risk.
I’d love to hear your personal remedies for removal and treatment of poison oak.
- At all cost, avoid exposure to poison oak, either from direct contact with the plant or indirectly through contaminated pets, clothes, tools, etc.
- If known contact occurs, immediately rinse the skin with copious amounts of water followed by soap and water or an immediate shower.
- Wash contaminated clothes in the washing machine, and don’t forget to wash your shoes and laces as well.
- If your rash blisters and oozes, use wet compresses with Domeboro, an over-the-counter treatment.
- If you can no longer stand the effects of the rash, see your health provider and be open to being treated with some form of cortisone, whether it’s a cream, pill or shot, and then expect a fairly rapid recovery.
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