Essential Hypertension: This is the most common cause of new onset hypertension, accounting for about 90-95% of cases. It is a diagnosis of exclusion, made after ruling out secondary causes of hypertension. Essential hypertension is often associated with a family history, obesity, and lifestyle factors such as a high-sodium diet, physical inactivity, and excessive alcohol consumption.

Chronic Kidney Disease (CKD): CKD is a common cause of secondary hypertension. Hypertension can both cause and be a consequence of CKD, creating a vicious cycle. Conditions like diabetic nephropathy, glomerulonephritis, and polycystic kidney disease can lead to CKD and hypertension.
Sleep Apnea: Sleep apnea is increasingly recognized as a cause of secondary hypertension. The intermittent hypoxia and frequent arousals during sleep can lead to increased sympathetic activity, contributing to elevated blood pressure.
Primary Aldosteronism: This condition, characterized by the excessive production of aldosterone, is a common cause of secondary hypertension. It can lead to hypokalemia and metabolic alkalosis, in addition to hypertension.

Pheochromocytoma: Although rare, pheochromocytoma is a potentially life-threatening cause of hypertension. It is characterized by episodic hypertension, tachycardia, palpitations, and sweating due to the excessive production of catecholamines by a tumor of the adrenal medulla.
Aortic Coarctation: This congenital condition involves narrowing of the aortic isthmus, leading to hypertension in the arms, with or without decreased blood pressure in the lower extremities. It can be associated with heart murmurs, delayed or diminished pulses in the lower limbs, and might be life-threatening if not diagnosed and treated properly.
Renal Artery Stenosis: This condition, often due to atherosclerosis or fibromuscular dysplasia, can lead to renovascular hypertension. It is crucial to diagnose and treat to prevent progression to end-stage renal disease and to control blood pressure.

Cushing's Syndrome: Caused by excessive exposure to cortisol, Cushing's syndrome can lead to hypertension, among other symptoms like weight gain, hirsutism, and glucose intolerance.
Hyperthyroidism: Although more commonly associated with tachycardia and weight loss, hyperthyroidism can also cause hypertension due to increased sympathetic activity and increased cardiac output.
Hyperparathyroidism: Primary hyperparathyroidism, often due to a parathyroid adenoma, can lead to hypertension, possibly through the effects of hypercalcemia on the vascular system and renal function.