POISON IVY, OAK, OR SUMAC

Main Symptoms

Localized red rash with small blisters following poison ivy, oak or sumac exposure
Rash is very itchy
Located on exposed body surfaces (such as the hands) or areas touched by the hands (e.g. the face or genitals).

General Information

Poison Ivy, Poison Sumac, and Poison Oak are three plants that can cause an itchy red rash in sensitive individuals. The oil contained in the plant leaves irritates the skin. The redness and blistering from the rash is often arranged in streaks or lines, because the leaves brush across the body in a line as an individual walks past.
Onset: Following a first-time exposure, the onset time for the rash is 1 to 2 weeks. For recurrences, the onset is 8 to 48 hours after the individual was in a forest or field.

Preventing the Rash!

Avoid Exposure: Avoid exposure to these plants, especially if you have had a bad reaction in the past.
Wash skin: If you are exposed, remove the irritating plant oil from your skin as soon as possible. Wash the exposed part of your body with soap and water within 30 minutes. Wash your clothes in warm soapy water.
IvyBlock: Is an over the counter cream. You put it on your skin before walking in the woods. It coats the skin and acts as a barrier to the irritating oil of the poison ivy/oak/sumac plants and prevents the rash from occurring. See http://www.ivyblock.com.

WHEN TO CALL YOUR DOCTOR FOR POISON IVY, OAK OR SUMAC

Call Your Doctor Now (night or day) If:

You feel weak or very sick
Difficulty breathing or severe coughing following exposure to burning weeds.
Rash looks infected (e.g., soft yellow scabs, pus or spreading redness)

Call Your Doctor Within 24 Hours (between 9 am and 4 pm) If:

You think you need to be seen
Swelling is severe (e.g. the eyes are swollen shut).
Severe poison ivy reaction in the past
Severe itching interferes with normal activities (e.g. work or school) or prevents sleep
Rash involves more than one fourth of the body
Face, eyes, lips or genitals are involved
Big blisters or oozing sores

Call Your Doctor During Weekday Office Hours If:

You have other questions or concerns
Rash lasts longer than 3 weeks

Self Care at Home If:

Mild poison ivy, oak or sumac rash and you don't think you need to be seen

^Back to Top

HOME CARE ADVICE FOR MILD RASH FROM POISON IVY, OAK OR SUMAC

Steroid Cream: Apply 1% hydrocortisone cream 4 times per day to reduce itching. Keep the cream in the refrigerator (Reason: it feels better if applied cold)
Local Cold: Soak the involved area in cool water for 20 minutes or massage it with an ice cube as often as necessary to reduce itching and oozing.
Benadryl: Take an antihistamine (e.g. diphenhydramine/Benadryl) if itching persists. The adult dosage of Benadryl is 25-50 mg by mouth 4 times daily.
- Do not take antihistamine medications such as Benadryl if you have prostate enlargement.
- Antihistamines may cause sleepiness. Do not drink, drive or operate dangerous machinery while taking antihistamines.
- Read the package instructions thoroughly on all medications that you take.
Avoid Scratching: Cut your fingernails short and try not to scratch so as to prevent a secondary infection from bacteria.
New Blisters Appear: If new blisters occur several days after the first ones, you probably have had ongoing contact with the irritating plant oil. To prevent recurrences: bathe all dogs, and wash all clothes and shoes that were with you on the day of exposure.
Contagiousness: Poison ivy or oak is not contagious to others.
Expected Course: Usually lasts 2 weeks. Treatment reduces the severity, not the length.
Call Your Doctor If:
- Rash lasts longer than 3 weeks
- It looks infected
- You become worse or develop any of the "Call Your Doctor" symptoms.

^Back to Top

Disclaimer: This information is not intended be a substitute for professional medical advice. It is provided for educational purposes only. You assume full responsibility for how you choose to use this information.

Reviewed 8/2004

Revised 7/2002

View Anatomic Index of Topics