Poison ivy is most dangerous in spring and summer

7/10/2014, 11:54 a.m.
Although spring and summer are prime times for glorious flowers and plants, the Medical Society of the State of New ...
Poison Ivy

Although spring and summer are prime times for glorious flowers and plants, the Medical Society of the State of New York cautions that spring and summer are also seasons when poison ivy is most dangerous. During spring and summer, poison ivy plants have plenty of sap, and the sap has plenty of urushiol, the chemical that produces the rash, blisters and itch.

Urushiol resides inside the plants, so brushing against the plant should not cause a reaction unless the plant is damaged, which is often the case. When stems or leaves are broken by animals or the wind, urushiol is released. Even avoiding all direct contact with the plants may not protect you. Urushiol can stick to pets and garden tools and other objects in the yard. Therefore, just touching that pet or object can cause a reaction in a susceptible person.

Most people exposed to poison ivy will develop an allergic reaction. Although sensitivity to poison ivy usually occurs only after several encounters with the plants, it may also occur after only one exposure.

Quick cleansing may prevent rash and itching

Poison ivy grows around lakes and streams and appears as a woody, ropelike vine, a trailing shrub on the ground or a free-standing shrub. The small stems arising from a larger stem usually have three groups of leaves but can have up to nine. The leaves are green in the summer and red in the fall. The plants may also have green flowers and white berries.

If you know you have been exposed to poison ivy, cleansing your skin within the first few minutes may remove the urushiol before it has a chance to penetrate. If more than 10 minutes have elapsed, cleansing may not help prevent the outbreak of the rash but can help prevent the urushiol from spreading over the skin.

If possible, stay outdoors while cleansing the skin with generous amounts of isopropyl (rubbing) alcohol. The alcohol removes not only the urushiol but also the skin’s protection, so any new urushiol will be able to penetrate twice as fast. It is therefore best to stay out of the area where contact occurred for the rest of the day. Then, still staying outdoors if possible, wash your skin with water (but not yet soap, which initially could pick up some of the urushiol from the surface and move it over more skin). After these first two cleansing steps, you can go inside and take a regular shower with soap and warm water.

What to do for rash, blisters and itching

If you do not wash the urushiol away quickly enough, or your skin is supersensitive to the urushiol, redness and swelling will usually appear about 12 to 48 hours after exposure. Blisters and itching will follow. For those rare people who react after their very first exposure, the rash appears after seven to 10 days.

The rash will only occur where urushiol has touched the skin. It does not spread throughout the body, although it may appear to do so when the rash develops at different times at different parts of the body. The rash, blisters and itch normally disappear in 14 to 20 days without any treatment.

The itching, however, often causes people to seek some relief. For mild cases, wet compresses or soaking in cool water may be effective. Oral antihistamines can also relieve itching. Try not to scratch blisters because fingernails may carry germs that could cause an infection. The FDA also considers over-the-counter topical corticosteroids (commonly called hydrocortisones under brand names such as Cortaid and Lanacort) safe and effective for temporary relief of itching associated with poison ivy.

For severe cases, topical corticosteroid drugs may be prescribed but are usually only effective if treatment begins within a few hours of exposure to urushiol. The Medical Society of the State of New York and the American Academy of Dermatology advise people who have had severe reactions in the past to contact a dermatologist as soon as possible after a new exposure. Oral corticosteroids may be prescribed if the rash is on the face or genitals or covers more than 30 percent of the body. The drug must be taken for at least 14 days, preferably over a three-week period. Shorter courses of treatment can cause a rebound with an even more severe rash.