What causes the Poison Ivy rash?
Poison Ivy and Poison Oak rashes are caused by an allergy to the juices of these plants – called Rhus plants. You don’t have to come in direct contact with the leaves, roots, or branches of Rhus plants to get the rash. The plant juice can reach your skin indirectly when you touch clothing or a pet that carries the plant juice.

Like other allergies, Rhus allergy is acquired; you’re not born with it. While some lucky people never become allergic to Rhus plants, most persons become sensitized at some point and remain allergic. Unfortunately, it is difficult to desensitize persons allergic to Rhus plants. This is typically performed through an allergist.

Is Poison Ivy contagious?
Your Poison Ivy rash is not contagious. The fluid in the blisters does not spread the rash.

How are Rhus rashes treated?
Rhus rashes are self-limited – sooner or later they clear up without treatment. Letting nature take its course is reasonable with mild Rhus rash. Severe Poison Ivy and Poison Oak rashes are treated by a doctor. Systemic cortisone is effective in treating Rhus rash.

When the swelling has gone down, cortisone cream or ointment will help your rash heal. Don’t put anything on your rash except the prescription cream, water, or a vinegar-water mixture. You may bathe or shower as usual; keep the water as cool as you can stand and don’t use soap on your rash, as it irritates.

Can Rhus rash be prevented?
The only way to prevent Rhus rash is to avoid contact with the plant juice. It’s traditional advice to wash with strong soap after poison ivy or poison oak exposure. This does no harm, but in order to prevent a rash, you have to wash within 15 – 30 minutes of exposure. If you can do so, simply washing with water and mild soap will effectively remove any plant juice from clothing, pets, or tools. Strong soaps are unnecessary. Rhus plants may cause rashes throughout the year. Roots and stems can cause a rash just as much as the leaves. If you don’t recognize Poison Ivy or Poison Oak plants, have friends or neighbors point them out so you can avoid them.

“You cannot go wrong with this dermatologist. Dr. Green and his staff are the very best! They go out of their way to assure patient satisfaction. I have used many services in the Bethesda location, and have always been more than satisfied. I highly recommend Dr. Green.” 

Susan E.

Dr. David Green, M.D.

Dr. David Green is a Board certified Dermatologist in Bethesda, Maryland. Dr. Green specializes in Dermatology, Dermatologic Cosmetic and Laser Surgery and the treatment of Varicose Veins and vascular disorders.

He is Certified by the American Board of Dermatology, is a Fellow of the American Academy of Dermatology, and a Member of the American Society for Dermatologic Surgery, and the American College of Phlebology. He treats patients from Maryland, Washington DC, Virginia and throughout the Mid Atlantic region.


Dr. David Green proudly offers services in his Bethesda, Maryland office.

4800 Montgomery Ln.,
Suite LL50
Bethesda, MD 20814
Phone: 301.907.7250


10.32.09: Delegation and Assignment of Performance of Cosmetic Medical Procedures and Use of Cosmetic Medical Devices. This is a Maryland safety regulation that governs who can legally perform medical cosmetic procedures.  Dr. Green administers all injectable treatments (including Botox™, Juvederm™, Voluma™, Kyblella™, and other fillers & Sclerotherapy) and laser treatments.