Allergies Health Center

Antihistamine pills are used to relieve the symptoms of the rash from poison ivy, oak, or sumac. Prescription medicines, such as corticosteroids, may be used for severe rashes. Medicines are also used to make the rash less severe.

Medication Choices

• Antihistamine pills can help relieve itching and dry blisters. Examples include Benadryl (diphenhydramine), which is an over-the-counter medicine, and Vistaril (hydroxyzine), which you get by prescription.
• Corticosteroids may be used to treat a moderate or severe rash. Corticosteroids may be given as pills, products that are spread on the skin (creams, ointments, gels), or shots.
• Barrier creams and lotions help prevent the plant oil (urushiol) from coming in contact with the skin or reduce the severity of a reaction. These creams vary in their potency and are not always effective.

You may be able to use a product that dissolves urushiol, such as Tecnu or Zanfel. These products are used to wash the oil off your skin or other objects. They may reduce the severity of a reaction or prevent one.

The most common complication of poison ivy, oak, or sumac rash is a secondary infection, usually caused by scratching. When this occurs, your doctor will probably prescribe a type of topical antibiotic cream if the infection is in a small area. Otherwise, you may need systemic antibiotics, given as pills or shots.

What To Think About

The following medicines should not be used for poison ivy, oak, or sumac rash, because they can cause allergy problems of their own:

• Antihistamines applied to the skin, such as diphenhydramine (found in Benadryl cream, spray, or gel).
• Anesthetics applied to the skin containing benzocaine (such as Lanacane).
• Antibiotics containing neomycin (such as Neosporin or Poly-Pred).