Can I use desoximetasone for relief of poison ivy itching?

Desoximetasone is a topical (for the skin) steroid. It reduces the actions of chemicals in the body that cause inflammation, redness, and swelling. Desoximetasone topical is used treat to the inflammation and itching caused by a number of skin conditions such as allergic reactions, eczema, and psoriasis.
Desoximetasone is a prescription medicine and as such should only be used on a doctors recommendation. It is a potent steroid and serious side-effects can occur if it is used inappropriately.
Check with your doctor or pharmacist.

This link is useful. It suggests using hydrocortisone cream which you can buy over the counter. http://www.drugs.com/enc/poison-ivy-oak-sumac-rash.html