The Call-On-Doc Guide for Poison Ivy, Sumac, and Oak

All three plants contain urushiol, an oily resin responsible for triggering allergic skin reactions. Urushiol is extremely potent—small amounts can cause significant inflammation—and it can remain active on skin, clothing, tools, and pet fur for extended periods.

Exposure occurs through:

• Direct skin contact with the plant

• Touching contaminated objects (clothing, gloves, gardening tools)

• Contact with pet fur that has brushed against the plant

• Inhaling smoke from burning plants (a medical emergency)

The reaction itself is not contagious. Fluid from blisters does not spread the rash.

Although they share the same allergen, these plants have distinct appearances.

Poison Ivy

• Typically has three leaflets (“leaves of three, let it be”)

• Grows as a vine or shrub

• Leaves may appear shiny and turn red in fall

Poison Oak

• Also has three leaflets

• Leaves resemble oak leaves

• Grows as a shrub or climbing vine

Poison Sumac

• Has 7–13 leaflets per stem

• Grows as a tall shrub or small tree

• Common in wet or swampy areas

• Causes some of the most severe reactions

Symptoms usually appear 12–72 hours after exposure, though timing can vary.

Common symptoms include:

• Intense itching

• Redness and swelling

• Linear or streak-like rash

• Blisters that may ooze clear fluid

• Skin tenderness or burning sensation

Severe reactions may include:

• Significant swelling (especially of the face, eyes, or genitals)

• Widespread rash

• Fever

• Difficulty breathing (requires emergency care)

Prompt action can reduce the severity of symptoms.

• Wash exposed skin within 10–30 minutes using soap and cool water

• Clean under fingernails thoroughly

• Remove and wash clothing separately in hot water

• Bathe pets that may have been exposed

• Avoid scratching to prevent infection

Do not use harsh scrubbing, alcohol wipes, or bleach on the skin.

Mild to Moderate Reactions

• Cool compresses

• Colloidal oatmeal baths

• Calamine lotion

• Oral antihistamines (for itch relief, not rash resolution)

• Low-potency topical corticosteroids

Moderate to Severe Reactions

Prescription treatment may be needed when:

• Rash covers large areas

• Blisters are extensive

• Symptoms involve the face or genitals

• Itching disrupts sleep or daily function

Medical treatments may include:

• Oral corticosteroids (often a tapered course over 10–21 days)

• Prescription-strength topical steroids

• Secondary infection treatment if skin becomes infected

Short steroid courses are not recommended, as they increase the risk of rebound dermatitis.

You should seek medical evaluation if:

• The rash is severe or spreading rapidly

• Symptoms involve the eyes, mouth, or genitals

• There is facial swelling

• Fever develops

• The rash does not improve within 7–10 days

• There are signs of infection (increasing pain, warmth, pus)

Call-On-Doc allows patients to receive evaluation and treatment online without waiting for in-person visits.

• Learn to identify poison plants before outdoor activities

• Wear long sleeves, pants, gloves, and closed shoes

• Use barrier creams containing bentoquatam when hiking

• Wash skin and clothing immediately after outdoor exposure

• Clean tools and gear after use

Pets should be rinsed after outdoor exposure, even if they show no symptoms.

Poison plant rashes can be miserable, but effective treatment is available. Call-On-Doc offers fast, convenient online care for poison ivy, poison oak, and poison sumac reactions, including prescription treatment when appropriate.

No appointments, no waiting rooms—just expert care when you need it.