What Is a Nonprescription Antihistamine Medication for Poison Oak?

Poison oak (Rhus diversiloba) is a plant that is commonly found as either a shrub or a vine and has leaves that are divided into three leaflets with lobed or toothed edges. The leaves have an oil which irritates the skin, causing inflammation, the formation of bumps and severe itching.

Types

• Zinc oxide ointments and calamine lotion are two recommended over-the-counter medications for treating poison oak. Caladryl should be avoided, since toxic levels of the active ingredient, diphenhydramine, may build up in the body when applied to open sores. A toxic buildup is more likely to occur if other products containing diphenhydramine, such as Benadryl, are used concurrently with Caladryl.

Forms

• Over-the-counter medications for poison oak are available as topical lotions or tablets. Topical lotions are typically more effective at preventing further spreading of the poison and for providing immediate relief.

Aloe

• Aloe may be applied to the skin to help alleviate itching and inflammation. Aloe-based products are available over the counter.

Baking Soda

• A paste consisting of three parts baking soda to one part water can be applied to a poison oak rash to help treat itching and inflammation.

Warning

• If a rash develops on the face or genitals, if there are signs of infection--such as odor or the leakage of a yellowish fluid--or if itching is severe, consult your physician immediately. Use of over-the-counter medication is likely not appropriate in these cases.