Adrenal disease causes skin pigmentation mainly due to increased secretion of adrenocorticotropic hormone and melanocyte-stimulating hormone, which manifests itself as a deepening of skin pigmentation all over the body, especially in exposed areas, friction areas, areolas and scars, and mucosal pigmentation in the gums, tongue and buccal mucosa.
Adrenal gland disease causing skin pigmentation is actually a rare condition in internal medicine, and prompt consultation with an endocrinologist is needed when these conditions occur.