Newswise — After years of keeping your high blood pressure in check with diet, exercise and medication, you learn that yours suddenly is too high.

The August issue of Mayo Clinic Health Letter discusses why you and your doctor will want to find the reason for the sudden jump, called secondary hypertension.

Usually, high blood pressure has no known cause. Hypertension of this sort is called essential hypertension and develops gradually over many years.

Secondary hypertension is less common and usually comes on quickly. It can be caused by over-the-counter and prescription medications or herbal supplements. Cold remedies, nasal decongestants and appetite suppressants containing pseudoephedrine may aggravate blood pressure. Prescription medications such as sibutramine (Meridia), steroids and others can elevate blood pressure. So can pain, acute stress or using alcohol, tobacco or caffeine.

A number of medical conditions -- such as reduced kidney function -- also could cause secondary hypertension. One of your kidneys' normal functions is to help control blood pressure. Essential hypertension or kidney disease can injure the kidneys, contributing to even higher blood pressure.

It's important to control both essential and secondary hypertension, since not doing so can lead to other health problems, including an increased risk of stroke.

Mayo Clinic Health Letter is an eight-page monthly newsletter of reliable, accurate and practical information on today's health and medical news. To subscribe, please call toll free 800-333-9037, extension 9PR1.