The itch is driving you crazy! You need help now!

Rashes caused by poison ivy, poison oak, and poison sumac look almost the same: raised, red, and blistered bumps in exposure areas. All are caused by hypersensitivity to urushiol-containing plants. The rash and itching begin 24 to 48 hours after exposure and worsen over the next few days. Assuming you’ve already showered when the rash appeared, poison ivy is not contagious. The only way to share it is if the vegetable oil is still on your skin and you touch someone else. The fluid from the blisters is not contagious.

Although in some cases people worry about their appearance, in most cases itching is what prompts them to seek medical attention.

Here are 5 tips for quick relief.

1. Use an over-the-counter antihistamine. Over-the-counter antihistamines are just as good as prescription antihistamines. The main benefit of using them is the decrease in itching, although they can reduce the swelling a bit. The main side effect is drowsiness with certain antihistamines, although this can be a benefit if the itchiness keeps you awake. Non-sedating antihistamines are Claritin (loratadine) and Zyrtec (cetirizine). Sedating antihistamines are Benadryl (diphenhydramine), chlorpheniramine, and doxylamine (found in sleeping pills and Nyquil). If these are effective in lessening your symptoms and the appearance of the rash is not a concern, an antihistamine may be all you need. The rash will go away on its own if you can wait, which usually takes 2-4 weeks.

2. Use an over-the-counter topical preparation. Calamine lotion and oatmeal baths help relieve itching, but they don’t actually reduce the rash. Hydrocortisone 1% cream is effective in reducing itching and healing the rash in mild cases. For a more serious reaction, prescription drugs may be needed. Hydrocortisone decreases the body’s reaction to the harmful oil, making the rash appear less red and irritated. Any of these can be used in addition to an antihistamine.

3. Call your doctor for a prescription. Your doctor may be willing to prescribe medication over the phone or may ask you to keep an appointment to make sure your self-diagnosis is correct. Prescription options include stronger steroid creams, steroid injections, and steroid pills. For small areas of rash, creams are best suited. However, for larger areas or rashes on the face (especially if the eyes are closed due to swelling) steroid injections or oral medications are appropriate. Usually, the rash begins to improve between 24 and 48 hours after starting treatment. Don’t make the mistake of stopping the medicine as soon as the rash improves; it is likely to come back if you leave it too soon. A five-day treatment plan is the minimum, but 10-14 days of medication is often recommended.

4. Watch for secondary infection. Any open area of ​​the skin can become infected. If the area of ​​redness is increasing, or especially if you see pus (not just clear blistering fluid), see your doctor to see if you need an antibiotic.

5. Do not use triple antibiotic ointment or Benadryl cream. When applied to the skin, both neomycin in triple antibiotic ointment and the active ingredient in Benadryl cream (diphenhydramine) can cause a rash that looks like poison ivy. Many patients have made the problem worse or have mistaken the diagnosis by using these over-the-counter preparations. (Diphenhydramine (Benadryl) taken by mouth does not cause this problem.)

Lastly, an ounce of prevention is worth a pound of cure. Avoid contact with the leaves, stems, and roots of plants, all of which contain urushiol. If you remove the plants, wear disposable gloves and throw away both the plants and the gloves. Burning the plant can put the chemical into the air and cause a serious rash for anyone exposed to the smoke.

Copyright 2010 Cynthia J. Koelker, MD