Essential hypertension (also called primary hypertension, or idiopathic hypertension) is the form of hypertension that by definition has no identifiable secondary cause. It is the most common type affecting 85% of those with high blood pressure. The remaining 15% is accounted for by various causes of secondary hypertension. Primary hypertension tends to be familial and is likely to be the consequence of an interaction between environmental and genetic factors. Prevalence of essential hypertension increases with age, and individuals with relatively high blood pressure at younger ages are at increased risk for the subsequent development of hypertension. Hypertension can increase the risk of cerebral, cardiac, and renal events. Classification A recent classification recommends blood pressure criteria for defining normal blood pressure, prehypertension, hypertension (stages I and II), and isolated systolic hypertension, which is a common occurrence among the elderly. These readings are based on the average of seated blood pressure readings that were properly measured during 2 or more office visits. In individuals older than 50 years, hypertension is considered to be present when a person's blood pressure is consistently at least 140 mmHg systolic or 90 mmHg diastolic. Patients with blood pressures over 130/80 mmHg along with Type 1 or Type 2 diabetes, or kidney disease require further treatment. Resistant hypertension is defined as the failure to reduce blood pressure to the appropriate level after taking a three-drug regimen. Guidelines for treating resistant hypertension have been published in the UK, and US. Risk factors Hypertension is one of the most common complex disorders. The etiology of hypertension differs widely amongst individuals within a large population. And by definition, essential hypertension has no identifiable cause. However, several risk factors have been identified. Genetic variation Having a personal family history of hypertension increases the likelihood that an individual develops it. In the United States, essential hypertension is four times more common in black than white people, accelerates more rapidly and is often more severe with higher mortality in black patients.There are numerous racial inequities that contribute to black individuals having higher prevalence of essential hypertension than white people. These racial disparity-related risk factors are less conspicuous. Discrimination may have both a direct and indirect effect on hypertension. Chronic stress, like that caused by discrimination, has been linked to a number of health problems. Black people often have a higher risk profile, which includes factors including stress, family history of cardiovascular disease, low