What condition do ACE inhibitors mainly treat?

ACE inhibitors, or Angiotensin-Converting Enzyme inhibitors, are primarily used to treat hypertension, which is high blood pressure. They work by inhibiting the enzyme that converts angiotensin I to angiotensin II, a substance that narrows blood vessels. By preventing this conversion, ACE inhibitors relax blood vessels, leading to a decrease in blood pressure. This medication not only helps to manage hypertension but also reduces the risk of complications such as heart disease and stroke.

The other options are conditions that are not primarily treated with ACE inhibitors. Dehydration typically requires fluid replacement rather than blood pressure medications. Dermatitis, which involves skin inflammation, is treated with topical or systemic anti-inflammatory therapies rather than ACE inhibitors. Anemia, a condition characterized by a lack of healthy red blood cells, is usually managed with iron supplements or other treatments aimed at increasing red blood cell production, rather than with antihypertensive medications. Therefore, the correct answer, focusing on the primary use of ACE inhibitors, is hypertension.