Final answer:
Hyperpigmentation due to Addison's disease is often first seen in areas subjected to friction, such as skin folds. It results from inadequate hormone production due to the immune system damaging the adrenal glands, and it is treated with hormone replacement therapy.
Step-by-step explanation:
The first place to see hyperpigmentation due to Addison's disease is often in areas that are exposed to friction, such as skin folds, elbows, knees, knuckles, and on scars or skin that is injured. This condition is usually a result of the body producing inadequate amounts of certain hormones, particularly cortisol and, in some cases, aldosterone, due to damaged adrenal glands. In Addison's disease, the adrenal glands are targeted and destroyed by the immune system, leading to the characteristic symptoms including fatigue, low blood pressure, and the distinctive hyperpigmentation of the skin. Treatment typically involves hormone replacement therapy to compensate for the insufficient production of adrenal hormones.