Dr. Sarah Marcus MD

FL Allergy & Asthma Therapy


4200 Coral Ridge Drive, Suite 227
 Coral Springs, FL 33321

Poison Ivy

Poison ivy is a common plant known to cause allergic reactions in a large percentage of people. These allergic reactions usually manifest as unsightly and uncomfortable rashes on the skin. Skin rashes from poison ivy, like those from poison oak and poison sumac, are precipitated by an oily substance called urushiol found in the leaves, stems and roots of the plant. Poison ivy is found growing all over the continental United States, so rashes from poison ivy are very common.

As with other allergens, individuals may build up an intolerance to urushiol over repeated exposures, believing themselves to be immune to the substance until they develop a severe reaction. A poison ivy rash only develops from direct contact with urushiol and is not contagious through contact with affected individuals or blister fluid.

Causes of Poison Ivy

There are three means of making contact with urushiol and developing an allergic reaction to poison ivy:

  • Direct skin contact with the plant itself
  • Contact with materials coated with urushiol, including clothing and pet fur
  • Breathing in the smoke of the burned plants

The last method of contact on the list is the most serious since the urushiol enters the nasal passages and lungs in this manner.

Symptoms of Poison Ivy

Typically, a rash, a form of dermatitis, develops on the skin within a day or two of contact with the plant or its oil. The rash itself is not contagious to others and will not spread to other areas of the affected individual unless repeated contact is made with urushiol that remains on the body or clothing. Usually, the rash of poison ivy begins as a red, swollen, itchy area which then develops into hives and blisters. The rash may appear to spread as different areas on the body, perhaps affected at different times, react to the allergen. The itching becomes increasingly severe and may interfere with normal activities and concentration. While not usually a serious condition, the poison ivy rash can be extremely uncomfortable and distracting.

In general, the poison ivy rash will disappear within a week or two. Patients are advised not to scratch the blisters, as bacteria from the fingernails may lead to infection. It is also advisable to bathe thoroughly, wash affected clothing, and clean any affected gear or upholstery that may contain trashes of the offending oil in order to avoid reinfection.

Treatments for Poison Ivy

While the poison ivy rash normally disappears on its own, when larger areas of the body are affected, recovery may take longer. Recommended home treatments for the itchy rash may include:

  • Taking baths in colloidal oatmeal
  • Applying hydrocortisone cream to the affected areas
  • Applying calamine lotion to the affected areas
  • Taking over-the-counter antihistamines
  • Taking over-the-counter pain relievers

Placing a cool, wet compress on the affected area several times a day may also help to soothe the itching and discomfort of a poison ivy rash.

Complications of Poison Ivy

While most cases of poison ivy are not serious, medical attention should be sought for any of the following symptoms:

  • High fever or other symptoms of infection
  • Widespread rash that does not improve in days
  • Rash in extremely sensitive areas, such as the eyes or genitals

A physician should be consulted for any symptoms of infection since an antibiotic may be necessary. If the rash is severe or resistant, the doctor may prescribe oral corticosteroids.

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