Urushiol induced contact dermatitis is the allergic reaction caused by poison oak. The mixture of pentadecylcatechols produced by the plant, which collectively is called urushiol, of the oleoresin within the sap of poison oak and related plants causes the allergic reaction. After injury, the sap leaks to the surface of the plant where the urushiol becomes a blackish lacquer after contact with oxygen. The oil adheres to almost anything with which it comes in contact, such as towels, blankets and even clothing. Clothing or other materials that contact the plant and then, before being washed, contact the skin are common causes of exposure. Urushiol oil can remain active for several years, so handling dead leaves or vines can cause a reaction. In addition, oil transferred from the plant to other objects (such as pet fur) can cause the rash if it comes into contact with the skin.

Urushiol is primarily found in the spaces between plant cells beneath the outer skin of the plant, so the effects of urushiol rash are less severe if the plant tissue remains undamaged on contact. Once the oil and resin are thoroughly washed from the skin, the rash is not contagious. Urushiol does not always spread once it has bonded with the skin, and cannot be transferred once the urushiol has been washed away.

Burning plant material is commonly said to create urushiol-laden smoke that causes systemic reaction as well as rash inside the throat, the lining of the lungs, and on the eyes, causing extreme pain and possibly fatal respiratory difficulty. Firefighters often get rashes and eye inflammation from smoke-related contact. In late fall or winter, there are no leaves on the plants, so they can be difficult to recognize. People have occasionally used its branches to toast marshmallows or hot dogs over a campfire with results that sent them to the hospital. A high-temperature, fully inflamed bonfire may incinerate the urushiol before it can cause harm, while a smoldering fire could vaporize the volatile oil and spread it as white smoke. If poison oak is eaten, the mucus lining of the mouth and digestive tract can be damaged.


The result is an allergic eczematous contact dermatitis characterized by redness, swelling, papules, vesicles, streaking, and then blistering. People vary greatly in their sensitivity to urushiol. Approximately 85% of adults will get a rash if they are exposed to 50 micrograms of purified urushiol. Some people are so sensitive, it only takes two micrograms of urushiol on the skin to initiate an allergic reaction (Epstein et al., 1974). At least 25% of people have very strong immune responses resulting in severe symptoms. In extreme cases, the allergic reaction can progress to anaphylaxis. Since the skin reaction is an allergic one, people may develop progressively stronger reactions after repeated exposures, or show no immune response on their first exposure, but show sensitivity on following exposures.

The rash takes one to four weeks, depending on severity and treatment, to run its course and normally does not leave scars. If there is no infection, most will resolve within two weeks. In rare cases, poison oak reactions may require hospitalization. Severe cases will have small (1–2 mm) clear fluid-filled blisters on the skin. The oozing fluids released by scratching blisters do not spread the poison. The fluid in the blisters is produced by the body and it is not urushiol itself. The appearance of a spreading rash indicates that some areas received more of the poison and reacted sooner than other areas or that contamination is still occurring from contact with objects to which the original poison was spread. The blisters and oozing result from blood vessels that develop gaps and leak fluid through the skin; if the skin is cooled, the vessels constrict and leak less. Pus-filled vesicles, containing a whitish fluid, may indicate a secondary infection. Excessive scratching may result in secondary infection, commonly by staphylococcal and streptococcal species; these may require the use of antibiotics.


The primary treatment step is washing. Then the uroshiol oil should be contained, removed and neutralized. Then the rash inflammation should be reduced, and blisters should be helped to heal.

Primary treatment involves washing exposed skin thoroughly with alcohol or soap or detergent, and cold water as soon as possible after exposure is discovered. Alcohol, soap, or detergent is very useful, because urushiol is an oil. If you do not have a solvent available, it is still helpful to rinse thoroughly in water as quickly as possible after contact. Commercial removing preparations, which are available in areas where poison oak grows, usually contain surfactants, such as the nonionic detergent Triton X-100 to solubilize urushiol; some preparations also contain abrasives. A study of a chemical neutralizer (Tecnu), the oil removing compound (Goop), and the surfactant (Dial ultra dishwashing soap), found 70%, 62%, and 56% protection relative to the possible maximum response. Within fifteen minutes of exposure, a majority of the uroshiol oil will react with skin proteins, forming a bound complex that is not removable short of removing the skin.

Areas affected should not be touched by any other part of the body, a simple ACE bandage wrapped around the area will suffice. Whatever bandage you use should be disposed of afterwards because it will absorb uroshiol oil. You should not scratch the affected area because that would irritate the rash and spread the uroshiol oil to other areas of the skin. Excessive scratching may result in secondary infection, commonly by staphylococcal and streptococcal species.

While the rash exists, two hot showers a day should be taken. The showers should be hot (but not scalding) with the caveats that this “also taxes the skin's integrity, opening pores and generally making it more vulnerable”, and is only for secondary treatment (not while cleaning urushiol from the skin, which should be done with cold water). Detergents, often made from petrochemicals, increase the permeability of skin membranes in a way that soaps and water alone do not. Sodium lauryl sulfate, the most common household detergent, has been shown to amplify the allergenicity of other substances (“increase antigen penetration”). So a hypoallergenic soap should be used, a soap often used by rash sufferers is pine tar soap. Some commercial pine tar soaps contain chemicals or preservatives, and you should avoid these. Of the pine tar soaps, Granpa Brands Pine Tar Soap is popular. After each shower, drying should be done with air or with disposable towels, a reusable towel should not be used because it would absorb the oil and recontaminate the skin later. Then a mixture of baking soda and oatmeal should be applied to the affected area. The baking soda, a base, reacts with and therefore neutralizes the uroshiol oil, which is acidic. The baking soda may also reduce the chance of infection by raising the pH. The oatmeal is thick and viscous making it easier to apply the baking soda to the skin and keep it there. The mixture can be made by mixing a tablespoon of baking soda per cup (250 mL) of oatmeal. A tablespoon of honey per cup can also be added to the mixture to reduce the chance of a bacterial secondary infection. Then the affected area should be wrapped in a disposable bandage. The wrapped area should be allowed to breathe. After a day, almost no unbound uroshiol oil will be removable with soap and water, however it is still a good idea to have a shower twice daily to remove dead skin bound to uroshiol oil, remove histamines, and to keep the skin as clean as possible to reduce the chance of infection.

The rash may be treated with Calamine lotion, however the U.S. Food and Drug Administration has ruled that the lotion's main components, a mixture of zinc oxide and ferric oxide, are useless for relieving pain and itching. The rash could also be treated with Burow's solution compresses, Jewelweed or baths to relieve discomfort. Overall, there is no evidence that either Calamine lotion or Burow's solution or Jewelweed is better than oatmeal and baking soda.

Ice, cold water, cooling lotions, or cold air do not help cure poison oak rashes, but cooling can reduce inflammation and soothe the itch. Those who have had a prior systemic reaction may be able to prevent subsequent exposure from turning systemic by avoiding heat and excitation of the circulatory system, and by applying moderate cold to any infected skin with biting pain.

In severe cases, antihistamines and hydrocortisone creams or antihistamines by mouth can be used to alleviate the symptoms of a developed rash. Nonprescription oral diphenhydramine (US tradename Benadryl) is the most commonly suggested antihistamine. Topical formulations containing diphenhydramine are available, but may further irritate the affected skin areas. In extremely severe cases, steroids such as prednisone are sometimes administered to attenuate the immune response. Prednisone is the most commonly prescribed systemic treatment, but can cause serious adrenal suppression changes, so it must be taken carefully, tapering off slowly.

Blisters should be left unbroken during healing. If the blisters are wrapped, the dressing should be kept as clean as possible, because weeping blisters are a hot bed for infection. The fluid from the resulting blisters does not spread poison oak to others. Honey can be applied on the affected area to reduce the chance of a bacterial secondary infection. Severe cases will have small (1–2 mm) clear fluid-filled blisters on the skin. Pus-filled vesicles, containing a whitish fluid, may indicate a secondary infection. If a bacterial secondary infection occurs, antibiotics may also be necessary.

Clothing, tools, and other objects that have been exposed to the oil should be washed in hot water, detergent or alcohol or soap, and baking soda, separately from anything else, to prevent further transmission. A soap often used to break up urushiol oil is Fels-Naptha. Washing should be done three times because even the tiny amount of uroshiol oil remaining after one wash may irritate the skin. The water should be hot because the hotter the water the more oil will be dissolved, cold water even with a cold water detergent is not as effective in removing the oil. A teaspoon of baking soda should be added per liter of water to neutralize any oil which is not washed away. Ordinary laundering with laundry detergent will remove urushiol from most clothing, but not from leather or suede.



A sauna treatment induces sweating which may clear the urushiol oil and associated histamines from deep in the skin. You should shower before a sauna treatment to wash off any oils which might block the pores, also drink a lot of water, or better yet a carbohydrate and electrolyte drink, to counter the water and electrolyte loss through sweat. After the sweating stops, you should have a quick shower to wash away the remaining allergens on the surface of the skin down the drain.

A side effect of a sauna treatment is that while the you are hot and sweating the kidney and liver function slows down. Also some women find saunas unpleasant while they are menstruating. In general, saunas have a powerful effect on the body and should be used with caution.

If you want to try a sauna treatment, make sure to drink beforehand, start with just a five minute session, and see if there are any side effects. If there are no problems, then you may slowly increase the length of the sessions to fifteen minutes. There is no need to push yourself to discomfort.

It is possible to get a mild version of the effect of a sauna by drinking beforehand, taking a hot shower to clear the skin, then soaking in a really hot bath of around 46 Celcius as measured with a bath thermometer. Even though this is the mild version, you should still be cautious, start with short sessions and see if there are any side effects, before going to longer sessions up to fifteen minutes or slightly higher temperatures (up to 48 Celcius).


Honey can be applied to the rash in any way that is suitable. One way is to use a syringe, if a syringe is used it should be washed after use with hot water to dissolve and wash away any remaining honey. After applying the honey to the affected area, it should be wrapped gently with gauze to prevent a mess. The wrapped area should be allowed to breathe. The bandages should be changed two to three times a day. There are no risks associated with applying honey to a plant induced rash as long as the honey is sanitary. Doctors in Uganda use this remedy to cure native plant related rashes. This remedy may work because the honey draws the poison out of your skin and then is absorbed into the bandage. This remedy may also help prevent the rash from spreading.

Vitamin C

Megadoses of Vitamin C may reduce itching within twenty minutes and dry up the blisters. The doses required are typically 1 to 4 grams per hour. Everybody is different, so one person might need more or less, but megadoses of 3 to 10 grams every few hours seems like a common range for people. Low doses of Vitamin C have little or no effect. If Vitamin C does work for you, the reduction in itchiness will occur within half an hour. If it does not work, then slowly increase the dose until you exceed bowel tolerance, where you are getting gas and/or diarrhea, and then back down the dose to what it was just before you exceeded your tolerance. If you still do not feel a reduction in itchiness at the tolerance level, then unfortunately oral Vitamin C doesn't work for your rash.

Topical applications of Vitamin C derivative cream may also reduce the itching. There is controversy concerning the best derivatives to use in a Vitamin C cream, some options are ascorbyl palmitate, tetrahexyldecyl ascorbate and magnesium ascorbyl phosphate. Vitamin C derivative creams include Vitamin C (magnesium ascorbyl phosphate) cream, and Jason Perfect Solutions Ester-C Lotion. You can make your own magnesium ascorbyl phosphate cream or just add magnesium ascorbyl phosphate to a cream you already use. Because Vitamin C derivative creams are usually expensive, and the quantities of the active ingredients are often omitted, it is worth trying to make your own cream.

Urushiol Separator

Most dermatologists state that there is nothing available which will break the bond between uroshiol and the skin. However, a couple of companies claim that their products can break that bond.

Zanfel has a clinical study that claims their Zanfel Poison Ivy Wash breaks the bond between urushiol oil and skin. However, the results of the study testing the product show only small improvements compared to a placebo, and the company does not link to the results, which are small compared to the product claims.

Ivy Off has another product which claims to break the bond between urushiol oil and skin, however, they don't even mention any study showing effectiveness.

Overall, it may be possible to make a urushiol separator, however, there is insufficient evidence to show that either of these products is a real separator. A study which could prove the effectiveness of a rash reduction product is relatively inexpensive, a good company would conduct such a study and link to the results.

Noxema Pad

Noxema anti-blemish pad. It absorbs oil from the skin, so it may be able to absorb urushiol oil from the skin. Once the urushiol oil has bonded with the skin, this pad should not be able to remove any more oil, however it might still be useful if it can remove some of the related histamines. If you do not feel a reduction in itchiness within half an hour, then it doesn't work for your rash.

Vitamin E Cream

Vitamin E cream or oil is used to decrease the itchiness, inflammation, discomfort, scar tissue, tenderness and overall appearance of skin irritations, burns and rashes, such as poison oak, and eczema. The Vitamin E cream should have at least 25,000 IU of Vitamin E. There is no study which indicates that a high amount of Vitamin E in a cream has adverse effects, but because it is affecting the immune response, it might have adverse effects. If the Vitamin E cream does work, itching should lessen within ten minutes and within an hour the rash should become less prominent. If the Vitamin E cream you are using does not work within ten minutes, try another brand with a lot of Vitamin E. If the next brand also doesn't work, then unfortunately Vitamin E probably doesn't work for your rash.

A Vitamin E cream with a high amount of Vitamin E is Gene's Vitamin E Cream, with 100,000 IU of Vitamin E. Unscrupulous companies add a bit of vitamin E to their creams in an effort to trick consumers. They slap a small sticker on their products that reads “Now contains Vitamin E,” and sure enough they get a boost in sales. Don’t fall for these types of tactics. You must check and double check that the specific Vitamin E cream which you wish to buy has a sufficient amount of Vitamin E. Sometimes, the cream might state the amount of Vitamin E as a percentage, in which case it should have at least 10%, preferably 25%. In general, because Vitamin E cream may have adverse effects at high doses, it is best to use Vitamin E cream carefully, applying only enough to reduce the inflammation, not just slathering it on.



When applied to skin prior to contact bentoquatam, the active ingredient in Ivy Block, will block the urushiol oil from reaching the skin. It is usually applied at least 15 minutes before possible contact with poison oak, and reapplied at least once every 4 hours for as long as the risk of contact with these plants continues. Bentoquatam will not soothe or heal a rash that has already developed from contact with urushiol oil.


The information presented is for informational purposes only and is not intended as a substitute for advice from your physician or other health care professional. You should consult with a health care professional before starting any diet, exercise or supplementation program, before taking any medication, or if you have or suspect you might have a health problem.

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